├── CODE_OF_CONDUCT.md ├── stylecop.json ├── .github └── workflows │ └── dotnet.yml ├── src ├── GroupCacheStubImpl │ ├── GroupCacheStubImpl.csproj │ ├── Log4NetLoggerAdapter.cs │ ├── OwinClient.cs │ ├── OwinServer.cs │ ├── OwinPool.cs │ └── OwinPoolPicker.cs └── GroupCache │ ├── GroupCache.csproj │ ├── LinkedListExtensions.cs │ ├── ReaderWriterLockSlimExtensions.cs │ ├── JumpHasher.cs │ ├── ICacheEntryValidator.cs │ ├── ExhaustedRetryException.cs │ ├── IGroupStat.cs │ ├── ICache.cs │ ├── KeyPrefixCacheDecorator.cs │ ├── DefaultGroupStat.cs │ ├── ILogger.cs │ ├── IGetter.cs │ ├── ReaderLockHolder.cs │ ├── WriterLockHolder.cs │ ├── SingleFlight.cs │ ├── UpgradeableReaderLockHolder.cs │ ├── NullCacheEntryValidator.cs │ ├── RetryContext.cs │ ├── NullLogger.cs │ ├── IGroupCacheClient.cs │ ├── SimpleRetryPolicy.cs │ ├── SemaphoreHolder.cs │ ├── MemoryCache.cs │ ├── Retry.cs │ ├── IPeerPicker.cs │ ├── CircuitBreakerClient.cs │ ├── Argument.cs │ ├── GroupCache.cs │ ├── LRUCache.cs │ └── DiskCache.cs ├── test └── GroupCacheStubTest │ ├── GroupCacheStubTest.csproj │ ├── UnitTestGroupStats.cs │ ├── TestDiskCache.cs │ ├── TestStub.cs │ └── TestGroupCache.cs ├── README.md ├── LICENSE ├── Directory.Packages.props ├── Directory.Build.props ├── GroupCacheDotNet.sln ├── SECURITY.md ├── .editorconfig └── .gitignore /CODE_OF_CONDUCT.md: -------------------------------------------------------------------------------- 1 | # Microsoft Open Source Code of Conduct 2 | 3 | This project has adopted the [Microsoft Open Source Code of Conduct](https://opensource.microsoft.com/codeofconduct/). 4 | 5 | Resources: 6 | 7 | - [Microsoft Open Source Code of Conduct](https://opensource.microsoft.com/codeofconduct/) 8 | - [Microsoft Code of Conduct FAQ](https://opensource.microsoft.com/codeofconduct/faq/) 9 | - Contact [opencode@microsoft.com](mailto:opencode@microsoft.com) with questions or concerns 10 | -------------------------------------------------------------------------------- /stylecop.json: -------------------------------------------------------------------------------- 1 | { 2 | "$schema": "https://raw.githubusercontent.com/DotNetAnalyzers/StyleCopAnalyzers/master/StyleCop.Analyzers/StyleCop.Analyzers/Settings/stylecop.schema.json", 3 | "settings": { 4 | "documentationRules": { 5 | "companyName": "Microsoft Corporation", 6 | "copyrightText": "Copyright (c) {companyName}. All rights reserved.\nLicensed under the {licenseName} license. See {licenseFile} file in the project root for full license information.", 7 | "variables": { 8 | "licenseName": "MIT", 9 | "licenseFile": "LICENSE" 10 | }, 11 | "headerDecoration": "--------------------------------------------------------------------------------------------------------------------" 12 | } 13 | } 14 | } 15 | -------------------------------------------------------------------------------- /.github/workflows/dotnet.yml: -------------------------------------------------------------------------------- 1 | # This workflow will build a .NET project 2 | # For more information see: https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-net 3 | 4 | name: .NET 5 | 6 | on: 7 | push: 8 | branches: [ "master" ] 9 | pull_request: 10 | branches: [ "master" ] 11 | 12 | jobs: 13 | build: 14 | 15 | runs-on: windows-latest 16 | 17 | steps: 18 | - uses: actions/checkout@v4 19 | - name: Setup .NET 20 | uses: actions/setup-dotnet@v4 21 | with: 22 | dotnet-version: 8.0.x 23 | - name: Restore dependencies 24 | run: dotnet restore 25 | - name: Build 26 | run: dotnet build --no-restore 27 | - name: Test 28 | run: dotnet test --no-build --verbosity normal 29 | -------------------------------------------------------------------------------- /src/GroupCacheStubImpl/GroupCacheStubImpl.csproj: -------------------------------------------------------------------------------- 1 | 2 | 3 | net472 4 | GroupCacheStub.GroupCacheStubImpl 5 | GroupCacheStub.GroupCacheStubImpl 6 | GroupCacheStub 7 | true 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | -------------------------------------------------------------------------------- /src/GroupCache/GroupCache.csproj: -------------------------------------------------------------------------------- 1 | 2 | 3 | netstandard2.0 4 | GroupCacheDotNet.GroupCache 5 | GroupCacheDotNet.GroupCache 6 | GroupCacheDotNet 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | -------------------------------------------------------------------------------- /test/GroupCacheStubTest/GroupCacheStubTest.csproj: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | net472 5 | GroupCacheStubTest 6 | GroupCacheStubTest 7 | true 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | 2 | # Contributing 3 | 4 | This project welcomes contributions and suggestions. Most contributions require you to agree to a 5 | Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us 6 | the rights to use your contribution. For details, visit https://cla.opensource.microsoft.com. 7 | 8 | When you submit a pull request, a CLA bot will automatically determine whether you need to provide 9 | a CLA and decorate the PR appropriately (e.g., status check, comment). Simply follow the instructions 10 | provided by the bot. You will only need to do this once across all repos using our CLA. 11 | 12 | This project has adopted the [Microsoft Open Source Code of Conduct](https://opensource.microsoft.com/codeofconduct/). 13 | For more information see the [Code of Conduct FAQ](https://opensource.microsoft.com/codeofconduct/faq/) or 14 | contact [opencode@microsoft.com](mailto:opencode@microsoft.com) with any additional questions or comments. 15 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | MIT License 2 | 3 | Copyright (c) Microsoft Corporation. 4 | 5 | Permission is hereby granted, free of charge, to any person obtaining a copy 6 | of this software and associated documentation files (the "Software"), to deal 7 | in the Software without restriction, including without limitation the rights 8 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 9 | copies of the Software, and to permit persons to whom the Software is 10 | furnished to do so, subject to the following conditions: 11 | 12 | The above copyright notice and this permission notice shall be included in all 13 | copies or substantial portions of the Software. 14 | 15 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 18 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 20 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 21 | SOFTWARE 22 | -------------------------------------------------------------------------------- /src/GroupCache/LinkedListExtensions.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | using System.Collections.Generic; 12 | 13 | public static class LinkedListExtensions 14 | { 15 | public static void MoveToFront(this LinkedList list, LinkedListNode node) 16 | { 17 | if (node.List != list) 18 | { 19 | throw new InvalidOperationException("The provided LinkedList should own the LinkedListNode"); 20 | } 21 | 22 | if (list.First == node) 23 | { 24 | return; 25 | } 26 | 27 | list.Remove(node); 28 | list.AddFirst(node); 29 | } 30 | } 31 | } 32 | -------------------------------------------------------------------------------- /src/GroupCache/ReaderWriterLockSlimExtensions.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System.Threading; 11 | 12 | public static class ReaderWriterLockSlimExtensions 13 | { 14 | public static ReaderLockHolder GetReaderLock(this ReaderWriterLockSlim rwLock) 15 | { 16 | return new ReaderLockHolder(rwLock); 17 | } 18 | 19 | public static WriterLockHolder GetWriterLock(this ReaderWriterLockSlim rwLock) 20 | { 21 | return new WriterLockHolder(rwLock); 22 | } 23 | 24 | public static UpgradeableReaderLockHolder GetUpgradeableReaderLock(this ReaderWriterLockSlim rwLock) 25 | { 26 | return new UpgradeableReaderLockHolder(rwLock); 27 | } 28 | } 29 | } -------------------------------------------------------------------------------- /src/GroupCache/JumpHasher.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | /// 11 | /// A C# implementation of the jump consistent hash from Lamping and Veach. 12 | /// Paper: http://arxiv.org/ftp/arxiv/papers/1406/1406.2294.pdf. 13 | /// 14 | public class JumpHasher 15 | { 16 | private const long JUMP = 1L << 31; 17 | private const ulong HASHSeed = 2862933555777941757; 18 | private const int BitShiftAmount = 33; 19 | 20 | // Hash returns the integer hash for the given key. 21 | public int Hash(ulong key, int n) 22 | { 23 | long b = -1; 24 | long j = 0; 25 | while (j < n) 26 | { 27 | b = j; 28 | key = (key * HASHSeed) + 1; 29 | j = (long)((b + 1L) * (JUMP / (double)((key >> BitShiftAmount) + 1L))); 30 | } 31 | 32 | return (int)b; 33 | } 34 | } 35 | } 36 | -------------------------------------------------------------------------------- /src/GroupCache/ICacheEntryValidator.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | using System.IO; 12 | using System.Threading; 13 | using System.Threading.Tasks; 14 | 15 | public class CacheEntryValidationFailedException : Exception 16 | { 17 | public CacheEntryValidationFailedException() 18 | : base() 19 | { 20 | } 21 | 22 | public CacheEntryValidationFailedException(string message) 23 | : base(message) 24 | { 25 | } 26 | 27 | public CacheEntryValidationFailedException(string message, Exception innerException) 28 | : base(message, innerException) 29 | { 30 | } 31 | } 32 | 33 | public abstract class ValidationStream : Stream 34 | { 35 | public abstract Task ValidateAsync(CancellationToken ct); 36 | } 37 | 38 | public interface ICacheEntryValidator 39 | { 40 | ValidationStream ValidateEntryPassThrough(string key, Stream streamPayload); 41 | } 42 | } -------------------------------------------------------------------------------- /src/GroupCache/ExhaustedRetryException.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | 12 | public class ExhaustedRetryException : Exception 13 | { 14 | /// 15 | /// Initializes a new instance of the class. 16 | /// 17 | public ExhaustedRetryException() 18 | { 19 | } 20 | 21 | /// 22 | /// Initializes a new instance of the class. 23 | /// 24 | /// 25 | public ExhaustedRetryException(string message) 26 | : base(message) 27 | { 28 | } 29 | 30 | /// 31 | /// Initializes a new instance of the class. 32 | /// 33 | /// 34 | /// 35 | public ExhaustedRetryException(string message, Exception inner) 36 | : base(message, inner) 37 | { 38 | } 39 | } 40 | } -------------------------------------------------------------------------------- /src/GroupCache/IGroupStat.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | 12 | /// 13 | /// Interface used to observe GroupCache internal operations 14 | /// This would be used to collect counters for monitoring. 15 | /// 16 | public interface IGroupStat 17 | { 18 | void TraceGets(string groupName); // any Get request, including from peers 19 | 20 | void TraceCacheHits(string groupName); // either cache was good 21 | 22 | void TracePeerLoads(string groupName); // either remote load or remote cache hit (not an error) 23 | 24 | void TraceLoadsDeduped(string groupName); // after singleflight 25 | 26 | void TraceLocalLoads(string groupName); // total good local loads 27 | 28 | void TraceServerRequests(string groupName); // gets that came over the network from peers 29 | 30 | void TraceRoundtripLatency(string groupName, TimeSpan ts); 31 | 32 | void TraceRetry(string groupName); 33 | 34 | void TraceItemOverCapacity(string groupName); 35 | 36 | void TraceConcurrentServerRequests(int v); 37 | } 38 | } 39 | -------------------------------------------------------------------------------- /src/GroupCache/ICache.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | using System.IO; 12 | using System.Threading; 13 | using System.Threading.Tasks; 14 | 15 | public interface ICache 16 | { 17 | Task GetOrAddAsync(string key, Func valueFactory, ICacheControl cacheControl, CancellationToken ct); 18 | 19 | event Action ItemOverCapacity; 20 | 21 | Task RemoveAsync(string key, CancellationToken ct); 22 | } 23 | 24 | public interface ICacheEntry 25 | { 26 | Stream Value(); 27 | 28 | void Ref(); 29 | 30 | Task DisposeAsync(); 31 | } 32 | 33 | public class EmptyCacheEntry : ICacheEntry 34 | { 35 | /// 36 | public Task DisposeAsync() 37 | { 38 | return Task.CompletedTask; 39 | } 40 | 41 | /// 42 | public void Ref() 43 | { 44 | } 45 | 46 | /// 47 | public Stream Value() 48 | { 49 | throw new NotImplementedException("Empty entry have no stream"); 50 | } 51 | } 52 | } 53 | -------------------------------------------------------------------------------- /Directory.Packages.props: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | true 5 | true 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | -------------------------------------------------------------------------------- /Directory.Build.props: -------------------------------------------------------------------------------- 1 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | true 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | true 21 | 22 | 23 | 24 | 25 | all 26 | runtime; build; native; contentfiles; analyzers 27 | 28 | 29 | all 30 | runtime; build; native; contentfiles; analyzers 31 | 32 | 33 | all 34 | runtime; build; native; contentfiles; analyzers 35 | 36 | 37 | 38 | 39 | -------------------------------------------------------------------------------- /src/GroupCache/KeyPrefixCacheDecorator.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | using System.IO; 12 | using System.Threading; 13 | using System.Threading.Tasks; 14 | 15 | public class KeyPrefixCacheDecorator : ICache 16 | { 17 | private readonly ICache decorated; 18 | private readonly string prefix; 19 | 20 | public KeyPrefixCacheDecorator(string prefix, ICache cache) 21 | { 22 | this.prefix = prefix; 23 | this.decorated = cache; 24 | this.decorated.ItemOverCapacity += (key) => this.ItemOverCapacity?.Invoke(key); 25 | } 26 | 27 | /// 28 | public event Action ItemOverCapacity; 29 | 30 | /// 31 | public Task GetOrAddAsync(string key, Func valueFactory, ICacheControl cacheControl, CancellationToken ct) 32 | { 33 | var newkey = this.prefix + key; 34 | return this.decorated.GetOrAddAsync(newkey, (str, stream, cc) => valueFactory(key, stream, cc), cacheControl, ct); 35 | } 36 | 37 | /// 38 | public Task RemoveAsync(string key, CancellationToken ct) 39 | { 40 | var newkey = this.prefix + key; 41 | return this.decorated.RemoveAsync(newkey, ct); 42 | } 43 | } 44 | } 45 | -------------------------------------------------------------------------------- /src/GroupCache/DefaultGroupStat.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | 12 | /// 13 | /// For unit-testing only. 14 | /// 15 | public class NullGroupStat : IGroupStat 16 | { 17 | /// 18 | public void TraceCacheHits(string groupName) 19 | { 20 | } 21 | 22 | /// 23 | public void TraceGets(string groupName) 24 | { 25 | } 26 | 27 | /// 28 | public void TraceLoadsDeduped(string groupName) 29 | { 30 | } 31 | 32 | /// 33 | public void TraceLocalLoads(string groupName) 34 | { 35 | } 36 | 37 | /// 38 | public void TracePeerLoads(string groupName) 39 | { 40 | } 41 | 42 | /// 43 | public void TraceServerRequests(string groupName) 44 | { 45 | } 46 | 47 | /// 48 | public void TraceRoundtripLatency(string groupName, TimeSpan ts) 49 | { 50 | } 51 | 52 | /// 53 | public void TraceRetry(string groupName) 54 | { 55 | } 56 | 57 | /// 58 | public void TraceItemOverCapacity(string groupName) 59 | { 60 | } 61 | 62 | /// 63 | public void TraceConcurrentServerRequests(int v) 64 | { 65 | } 66 | } 67 | } 68 | -------------------------------------------------------------------------------- /src/GroupCache/ILogger.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | 12 | public interface ILogger 13 | { 14 | /// Logs a message with severity Debug. 15 | void Debug(string message); 16 | 17 | /// Logs a formatted message with severity Debug. 18 | void Debug(string format, params object[] formatArgs); 19 | 20 | /// Logs a message with severity Info. 21 | void Info(string message); 22 | 23 | /// Logs a formatted message with severity Info. 24 | void Info(string format, params object[] formatArgs); 25 | 26 | /// Logs a message with severity Warning. 27 | void Warning(string message); 28 | 29 | /// Logs a formatted message with severity Warning. 30 | void Warning(string format, params object[] formatArgs); 31 | 32 | /// Logs a message and an associated exception with severity Warning. 33 | void Warning(Exception exception, string message); 34 | 35 | /// Logs a message with severity Error. 36 | void Error(string message); 37 | 38 | /// Logs a formatted message with severity Error. 39 | void Error(string format, params object[] formatArgs); 40 | 41 | /// Logs a message and an associated exception with severity Error. 42 | void Error(Exception exception, string message); 43 | } 44 | } 45 | -------------------------------------------------------------------------------- /src/GroupCache/IGetter.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | using System.IO; 12 | using System.Threading; 13 | using System.Threading.Tasks; 14 | 15 | public interface ICacheControl 16 | { 17 | // Whether cache must not store any response. 18 | bool NoStore { get; set; } 19 | } 20 | 21 | public class CacheControl : ICacheControl 22 | { 23 | // Whether cache must not store any response. 24 | /// 25 | public bool NoStore { get; set; } = false; 26 | } 27 | 28 | /// 29 | /// A Getter loads data for identified by key. 30 | /// 31 | /// The returned data must be unversioned. 32 | /// That is, key must uniquely describe the loaded data 33 | /// without an implicit current time, and without relying on cache expiration mechanisms. 34 | /// 35 | public interface IGetter 36 | { 37 | Task GetAsync(string key, Stream sink, ICacheControl cacheControl, CancellationToken ct); 38 | } 39 | 40 | public sealed class GetterFunc : IGetter 41 | { 42 | private readonly Func func; 43 | 44 | public GetterFunc(Func func) 45 | { 46 | this.func = func; 47 | } 48 | 49 | /// 50 | public Task GetAsync(string key, Stream sink, ICacheControl cacheControl, CancellationToken ct) 51 | { 52 | return this.func(key, sink, cacheControl, ct); 53 | } 54 | } 55 | } 56 | -------------------------------------------------------------------------------- /src/GroupCache/ReaderLockHolder.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | using System.Threading; 12 | 13 | /// 14 | /// Helper class that makes it easier to ensure proper usage of a for readers by providing support for 16 | /// and the using keyword. 17 | /// 18 | public sealed class ReaderLockHolder : IDisposable 19 | { 20 | private readonly ReaderWriterLockSlim rwLock; 21 | 22 | // Track whether Dispose has been called. 23 | private bool disposed = false; 24 | 25 | /// 26 | /// Initializes a new instance of the class. 27 | /// Acquires a reader lock on the rwLock received with no timeout specified. 28 | /// 29 | public ReaderLockHolder(ReaderWriterLockSlim rwLock) 30 | { 31 | if (rwLock == null) 32 | { 33 | throw new ArgumentNullException("rwLock"); 34 | } 35 | 36 | this.rwLock = rwLock; 37 | this.rwLock.EnterReadLock(); 38 | } 39 | 40 | /// 41 | public void Dispose() 42 | { 43 | this.Dispose(true); 44 | } 45 | 46 | private void Dispose(bool disposing) 47 | { 48 | if (disposing && !this.disposed) 49 | { 50 | if (this.rwLock.IsReadLockHeld) 51 | { 52 | this.rwLock.ExitReadLock(); 53 | } 54 | 55 | this.disposed = true; 56 | } 57 | } 58 | } 59 | } -------------------------------------------------------------------------------- /src/GroupCache/WriterLockHolder.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | using System.Threading; 12 | 13 | /// 14 | /// Helper class that makes it easier to ensure proper usage of a 15 | /// for writers by providing support for and the using keyword. 16 | /// 17 | public sealed class WriterLockHolder : IDisposable 18 | { 19 | private readonly ReaderWriterLockSlim rwLock; 20 | 21 | // Track whether Dispose has been called. 22 | private bool disposed = false; 23 | 24 | /// 25 | /// Initializes a new instance of the class. 26 | /// Acquires a reader lock on the rwLock received 27 | /// with no timeout specified. 28 | /// 29 | public WriterLockHolder(ReaderWriterLockSlim rwLock) 30 | { 31 | if (rwLock == null) 32 | { 33 | throw new ArgumentNullException("rwLock"); 34 | } 35 | 36 | this.rwLock = rwLock; 37 | this.rwLock.EnterWriteLock(); 38 | } 39 | 40 | /// 41 | public void Dispose() 42 | { 43 | this.Dispose(true); 44 | } 45 | 46 | private void Dispose(bool disposing) 47 | { 48 | if (disposing && !this.disposed) 49 | { 50 | if (this.rwLock.IsWriteLockHeld) 51 | { 52 | this.rwLock.ExitWriteLock(); 53 | } 54 | 55 | this.disposed = true; 56 | } 57 | } 58 | } 59 | } -------------------------------------------------------------------------------- /src/GroupCache/SingleFlight.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | using System.Collections.Concurrent; 12 | using System.Threading.Tasks; 13 | 14 | /// 15 | /// Provides a duplicate function call suppression mechanism. 16 | /// 17 | /// Return type of the callback. 18 | public sealed class SingleFlight 19 | { 20 | private readonly ConcurrentDictionary> flights = new ConcurrentDictionary>(); 21 | 22 | /// 23 | /// Initializes a new instance of the class. 24 | /// 25 | public SingleFlight() 26 | { 27 | } 28 | 29 | /// 30 | /// 31 | /// 32 | /// 33 | /// 34 | /// A representing the result of the asynchronous operation. 35 | public async Task DoAsync(string key, Func> valueFactory) 36 | { 37 | TaskCompletionSource tcs = new TaskCompletionSource(); 38 | var result = this.flights.GetOrAdd(key, tcs); 39 | if (result != tcs) 40 | { 41 | return await result.Task.ConfigureAwait(false); 42 | } 43 | 44 | try 45 | { 46 | var value = await valueFactory().ConfigureAwait(false); 47 | tcs.TrySetResult(value); 48 | } 49 | catch (Exception ex) 50 | { 51 | tcs.SetException(ex); 52 | } 53 | 54 | this.flights.TryRemove(key, out _); 55 | return await tcs.Task.ConfigureAwait(false); 56 | } 57 | } 58 | } 59 | -------------------------------------------------------------------------------- /test/GroupCacheStubTest/UnitTestGroupStats.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCacheStubTest 9 | { 10 | using System; 11 | using System.Threading; 12 | using GroupCache; 13 | 14 | /// 15 | /// For unit-testing only. 16 | /// 17 | public class UnitTestGroupStat : IGroupStat 18 | { 19 | public int CacheHits = 0; 20 | public int Gets = 0; 21 | public int LoadsDeduped = 0; 22 | public int LocalLoads = 0; 23 | public int PeerLoads = 0; 24 | public int ServerRequests = 0; 25 | 26 | public void TraceCacheHits(string groupName) 27 | { 28 | Interlocked.Increment(ref this.CacheHits); 29 | } 30 | 31 | public void TraceGets(string groupName) 32 | { 33 | Interlocked.Increment(ref this.Gets); 34 | } 35 | 36 | public void TraceLoadsDeduped(string groupName) 37 | { 38 | Interlocked.Increment(ref this.LoadsDeduped); 39 | } 40 | 41 | public void TraceLocalLoads(string groupName) 42 | { 43 | Interlocked.Increment(ref this.LocalLoads); 44 | } 45 | 46 | public void TracePeerLoads(string groupName) 47 | { 48 | Interlocked.Increment(ref this.PeerLoads); 49 | } 50 | 51 | public void TraceServerRequests(string groupName) 52 | { 53 | Interlocked.Increment(ref this.ServerRequests); 54 | } 55 | 56 | public void TraceRoundtripLatency(string groupName, TimeSpan ts) 57 | { 58 | } 59 | 60 | public void TraceRetry(string groupName) 61 | { 62 | } 63 | 64 | public void TraceItemOverCapacity(string groupName) 65 | { 66 | } 67 | 68 | public void TraceConcurrentServerRequests(int v) 69 | { 70 | } 71 | } 72 | } 73 | -------------------------------------------------------------------------------- /src/GroupCache/UpgradeableReaderLockHolder.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | using System.Threading; 12 | 13 | /// 14 | /// Helper class that makes it easier to ensure proper usage of a 15 | /// for readers by providing support for and the using keyword. 16 | /// 17 | public sealed class UpgradeableReaderLockHolder : IDisposable 18 | { 19 | /// 20 | /// Initializes a new instance of the class. 21 | /// Acquires a reader lock on the rwLock received 22 | /// with no timeout specified. 23 | /// 24 | public UpgradeableReaderLockHolder(ReaderWriterLockSlim rwLock) 25 | { 26 | if (rwLock == null) 27 | { 28 | throw new ArgumentNullException("rwLock"); 29 | } 30 | 31 | this.rwLock = rwLock; 32 | this.rwLock.EnterUpgradeableReadLock(); 33 | } 34 | 35 | /// 36 | public void Dispose() 37 | { 38 | this.Dispose(true); 39 | } 40 | 41 | public WriterLockHolder GetWriterLock() 42 | { 43 | return this.rwLock.GetWriterLock(); 44 | } 45 | 46 | private void Dispose(bool disposing) 47 | { 48 | if (disposing && !this.disposed) 49 | { 50 | if (this.rwLock.IsUpgradeableReadLockHeld) 51 | { 52 | this.rwLock.ExitUpgradeableReadLock(); 53 | } 54 | 55 | this.disposed = true; 56 | } 57 | } 58 | 59 | private readonly ReaderWriterLockSlim rwLock; 60 | 61 | // Track whether Dispose has been called. 62 | private bool disposed = false; 63 | } 64 | } 65 | -------------------------------------------------------------------------------- /GroupCacheDotNet.sln: -------------------------------------------------------------------------------- 1 | 2 | Microsoft Visual Studio Solution File, Format Version 12.00 3 | # Visual Studio Version 17 4 | VisualStudioVersion = 17.13.35931.197 5 | MinimumVisualStudioVersion = 10.0.40219.1 6 | Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{8EC462FD-D22E-90A8-E5CE-7E832BA40C5D}" 7 | ProjectSection(SolutionItems) = preProject 8 | .editorconfig = .editorconfig 9 | Directory.Build.props = Directory.Build.props 10 | Directory.Packages.props = Directory.Packages.props 11 | stylecop.json = stylecop.json 12 | EndProjectSection 13 | EndProject 14 | Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "GroupCache", "src\GroupCache\GroupCache.csproj", "{8D9CF82B-1DAA-9E8A-8535-E14122FB27FD}" 15 | EndProject 16 | Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "GroupCacheStubImpl", "src\GroupCacheStubImpl\GroupCacheStubImpl.csproj", "{C62F2717-4EBF-DFAD-CC07-920214115635}" 17 | EndProject 18 | Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "GroupCacheStubTest", "test\GroupCacheStubTest\GroupCacheStubTest.csproj", "{94E451B2-27D2-A6BF-9613-C10541EEBFDB}" 19 | EndProject 20 | Global 21 | GlobalSection(SolutionConfigurationPlatforms) = preSolution 22 | Debug|Any CPU = Debug|Any CPU 23 | Release|Any CPU = Release|Any CPU 24 | EndGlobalSection 25 | GlobalSection(ProjectConfigurationPlatforms) = postSolution 26 | {8D9CF82B-1DAA-9E8A-8535-E14122FB27FD}.Debug|Any CPU.ActiveCfg = Debug|Any CPU 27 | {8D9CF82B-1DAA-9E8A-8535-E14122FB27FD}.Debug|Any CPU.Build.0 = Debug|Any CPU 28 | {8D9CF82B-1DAA-9E8A-8535-E14122FB27FD}.Release|Any CPU.ActiveCfg = Release|Any CPU 29 | {8D9CF82B-1DAA-9E8A-8535-E14122FB27FD}.Release|Any CPU.Build.0 = Release|Any CPU 30 | {C62F2717-4EBF-DFAD-CC07-920214115635}.Debug|Any CPU.ActiveCfg = Debug|Any CPU 31 | {C62F2717-4EBF-DFAD-CC07-920214115635}.Debug|Any CPU.Build.0 = Debug|Any CPU 32 | {C62F2717-4EBF-DFAD-CC07-920214115635}.Release|Any CPU.ActiveCfg = Release|Any CPU 33 | {C62F2717-4EBF-DFAD-CC07-920214115635}.Release|Any CPU.Build.0 = Release|Any CPU 34 | {94E451B2-27D2-A6BF-9613-C10541EEBFDB}.Debug|Any CPU.ActiveCfg = Debug|Any CPU 35 | {94E451B2-27D2-A6BF-9613-C10541EEBFDB}.Debug|Any CPU.Build.0 = Debug|Any CPU 36 | {94E451B2-27D2-A6BF-9613-C10541EEBFDB}.Release|Any CPU.ActiveCfg = Release|Any CPU 37 | {94E451B2-27D2-A6BF-9613-C10541EEBFDB}.Release|Any CPU.Build.0 = Release|Any CPU 38 | EndGlobalSection 39 | GlobalSection(SolutionProperties) = preSolution 40 | HideSolutionNode = FALSE 41 | EndGlobalSection 42 | GlobalSection(ExtensibilityGlobals) = postSolution 43 | SolutionGuid = {2D1F54F4-4937-4DFA-A5D3-94013FC1975A} 44 | EndGlobalSection 45 | EndGlobal 46 | -------------------------------------------------------------------------------- /test/GroupCacheStubTest/TestDiskCache.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCacheStubTest 9 | { 10 | using System.Collections.Generic; 11 | using System.Threading; 12 | using System.Threading.Tasks; 13 | using GroupCache; 14 | using Xunit; 15 | 16 | public class TestDiskCache 17 | { 18 | // Test have random failure disabling for now 19 | [Fact] 20 | public void TestConcurrentCacheAccess() 21 | { 22 | var mockFileSystem = new MockFileSystem(); 23 | var diskCache = new DiskCache("c:\\CacheRoot", 10, mockFileSystem); 24 | long cacheFill = 0; 25 | List tasks = new List(); 26 | for (int i = 0; i < 24; i++) 27 | { 28 | var t = Task.Run(async () => 29 | { 30 | for (int k = 0; k < 100; k++) 31 | { 32 | for (int j = 0; j < 40; j++) 33 | { 34 | var keyString = j.ToString(); 35 | var cacheEntry = await diskCache.GetOrAddAsync( 36 | keyString, 37 | (key, sink, cacheControl) => 38 | { 39 | Interlocked.Increment(ref cacheFill); 40 | var keystream = key.StringToStream(); 41 | return keystream.CopyToAsync(sink); 42 | }, new CacheControl(), CancellationToken.None); 43 | try 44 | { 45 | var cacheEntryString = cacheEntry.Value().StreamToString(); 46 | Xunit.Assert.Equal(keyString, cacheEntryString); 47 | } 48 | finally 49 | { 50 | await cacheEntry.DisposeAsync(); 51 | } 52 | } 53 | } 54 | }); 55 | tasks.Add(t); 56 | } 57 | 58 | Task.WaitAll(tasks.ToArray()); 59 | Xunit.Assert.Equal(10, mockFileSystem.DirectoryGetFiles("c:\\CacheRoot\\tmp").Length); 60 | } 61 | } 62 | } 63 | -------------------------------------------------------------------------------- /SECURITY.md: -------------------------------------------------------------------------------- 1 | 2 | 3 | ## Security 4 | 5 | Microsoft takes the security of our software products and services seriously, which includes all source code repositories managed through our GitHub organizations, which include [Microsoft](https://github.com/Microsoft), [Azure](https://github.com/Azure), [DotNet](https://github.com/dotnet), [AspNet](https://github.com/aspnet), [Xamarin](https://github.com/xamarin), and [our GitHub organizations](https://opensource.microsoft.com/). 6 | 7 | If you believe you have found a security vulnerability in any Microsoft-owned repository that meets [Microsoft's definition of a security vulnerability](https://docs.microsoft.com/en-us/previous-versions/tn-archive/cc751383(v=technet.10)), please report it to us as described below. 8 | 9 | ## Reporting Security Issues 10 | 11 | **Please do not report security vulnerabilities through public GitHub issues.** 12 | 13 | Instead, please report them to the Microsoft Security Response Center (MSRC) at [https://msrc.microsoft.com/create-report](https://msrc.microsoft.com/create-report). 14 | 15 | If you prefer to submit without logging in, send email to [secure@microsoft.com](mailto:secure@microsoft.com). If possible, encrypt your message with our PGP key; please download it from the [Microsoft Security Response Center PGP Key page](https://www.microsoft.com/en-us/msrc/pgp-key-msrc). 16 | 17 | You should receive a response within 24 hours. If for some reason you do not, please follow up via email to ensure we received your original message. Additional information can be found at [microsoft.com/msrc](https://www.microsoft.com/msrc). 18 | 19 | Please include the requested information listed below (as much as you can provide) to help us better understand the nature and scope of the possible issue: 20 | 21 | * Type of issue (e.g. buffer overflow, SQL injection, cross-site scripting, etc.) 22 | * Full paths of source file(s) related to the manifestation of the issue 23 | * The location of the affected source code (tag/branch/commit or direct URL) 24 | * Any special configuration required to reproduce the issue 25 | * Step-by-step instructions to reproduce the issue 26 | * Proof-of-concept or exploit code (if possible) 27 | * Impact of the issue, including how an attacker might exploit the issue 28 | 29 | This information will help us triage your report more quickly. 30 | 31 | If you are reporting for a bug bounty, more complete reports can contribute to a higher bounty award. Please visit our [Microsoft Bug Bounty Program](https://microsoft.com/msrc/bounty) page for more details about our active programs. 32 | 33 | ## Preferred Languages 34 | 35 | We prefer all communications to be in English. 36 | 37 | ## Policy 38 | 39 | Microsoft follows the principle of [Coordinated Vulnerability Disclosure](https://www.microsoft.com/en-us/msrc/cvd). 40 | 41 | -------------------------------------------------------------------------------- /src/GroupCache/NullCacheEntryValidator.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System.IO; 11 | using System.Threading; 12 | using System.Threading.Tasks; 13 | 14 | public class NullCacheEntryValidator : ICacheEntryValidator 15 | { 16 | /// 17 | public ValidationStream ValidateEntryPassThrough(string key, Stream sink) 18 | { 19 | return new NullValidationStream(sink); 20 | } 21 | } 22 | 23 | public class NullValidationStream : ValidationStream 24 | { 25 | private readonly Stream sink; 26 | 27 | public NullValidationStream(Stream sink) 28 | { 29 | this.sink = sink; 30 | } 31 | 32 | /// 33 | public override bool CanRead => this.sink.CanRead; 34 | 35 | /// 36 | public override bool CanSeek => this.sink.CanSeek; 37 | 38 | /// 39 | public override bool CanWrite => this.sink.CanWrite; 40 | 41 | /// 42 | public override long Length => this.sink.Length; 43 | 44 | /// 45 | public override long Position { get => this.sink.Position; set => this.sink.Position = value; } 46 | 47 | /// 48 | public override void Flush() 49 | { 50 | this.sink.Flush(); 51 | } 52 | 53 | /// 54 | public override int Read(byte[] buffer, int offset, int count) 55 | { 56 | return this.sink.Read(buffer, offset, count); 57 | } 58 | 59 | /// 60 | public override long Seek(long offset, SeekOrigin origin) 61 | { 62 | return this.sink.Seek(offset, origin); 63 | } 64 | 65 | /// 66 | public override void SetLength(long value) 67 | { 68 | this.sink.SetLength(value); 69 | } 70 | 71 | /// 72 | public override Task ValidateAsync(CancellationToken ct) 73 | { 74 | return Task.CompletedTask; 75 | } 76 | 77 | /// 78 | public override void Write(byte[] buffer, int offset, int count) 79 | { 80 | this.sink.Write(buffer, offset, count); 81 | } 82 | } 83 | } -------------------------------------------------------------------------------- /src/GroupCacheStubImpl/Log4NetLoggerAdapter.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCacheStub 9 | { 10 | using System; 11 | 12 | public class Log4NetLoggerAdapter : GroupCache.ILogger 13 | { 14 | private readonly log4net.ILog innerLogger; 15 | 16 | /// 17 | /// Initializes a new instance of the class. 18 | /// 19 | /// 20 | public Log4NetLoggerAdapter(log4net.ILog log4NetLogger) 21 | { 22 | this.innerLogger = log4NetLogger; 23 | } 24 | 25 | /// 26 | public void Debug(string message) 27 | { 28 | this.innerLogger.Debug(message); 29 | } 30 | 31 | /// 32 | public void Debug(string format, params object[] formatArgs) 33 | { 34 | this.innerLogger.DebugFormat(format, formatArgs); 35 | } 36 | 37 | /// 38 | public void Error(string message) 39 | { 40 | this.innerLogger.Error(message); 41 | } 42 | 43 | /// 44 | public void Error(string format, params object[] formatArgs) 45 | { 46 | this.innerLogger.ErrorFormat(format, formatArgs); 47 | } 48 | 49 | /// 50 | public void Error(Exception exception, string message) 51 | { 52 | this.innerLogger.Error(message, exception); 53 | } 54 | 55 | /// 56 | public void Info(string message) 57 | { 58 | this.innerLogger.Info(message); 59 | } 60 | 61 | /// 62 | public void Info(string format, params object[] formatArgs) 63 | { 64 | this.innerLogger.InfoFormat(format, formatArgs); 65 | } 66 | 67 | /// 68 | public void Warning(string message) 69 | { 70 | this.innerLogger.Warn(message); 71 | } 72 | 73 | /// 74 | public void Warning(string format, params object[] formatArgs) 75 | { 76 | this.innerLogger.WarnFormat(format, formatArgs); 77 | } 78 | 79 | /// 80 | public void Warning(Exception exception, string message) 81 | { 82 | this.innerLogger.Warn(message, exception); 83 | } 84 | } 85 | } 86 | -------------------------------------------------------------------------------- /src/GroupCache/RetryContext.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | 12 | /// 13 | /// Low-level access to ongoing retry operation. 14 | /// Normally not needed by clients, but can be used to alter the course of the retry,. 15 | /// 16 | public class RetryContext 17 | { 18 | private Exception exception; 19 | private int count = 0; 20 | private TimeSpan backOffPeriod; 21 | private readonly int maxAttempts; 22 | 23 | /// 24 | /// Gets the number of attempts before a retry becomes impossible. 25 | /// 26 | public int RetryCount 27 | { 28 | get { return this.count; } 29 | } 30 | 31 | /// 32 | /// Gets accessor for the exception object that caused the current retry. 33 | /// 34 | public Exception LastException 35 | { 36 | get { return this.exception; } 37 | } 38 | 39 | /// 40 | /// Gets accessor for the backoff period of the current policy. 41 | /// 42 | public TimeSpan BackOffPeriod 43 | { 44 | get { return this.backOffPeriod; } 45 | } 46 | 47 | /// 48 | /// Gets accessor for the max attempts of the current policy. 49 | /// 50 | public int MaxAttempts 51 | { 52 | get { return this.maxAttempts; } 53 | } 54 | 55 | /// 56 | /// Gets or sets a value indicating whether signal to the framework that no more attempts should be made to try or retry the current RetryCallback. 57 | /// 58 | public bool IsExhausted { get; set; } 59 | 60 | /// 61 | /// Initializes a new instance of the class. 62 | /// 63 | /// 64 | /// 65 | public RetryContext(int maxAttempts, TimeSpan backOffPeriod) 66 | { 67 | this.maxAttempts = maxAttempts; 68 | this.backOffPeriod = backOffPeriod; 69 | this.IsExhausted = false; 70 | } 71 | 72 | public void RegisterException(Exception ex) 73 | { 74 | this.exception = ex; 75 | if (ex != null) 76 | { 77 | this.count++; 78 | } 79 | } 80 | } 81 | } -------------------------------------------------------------------------------- /src/GroupCache/NullLogger.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | 12 | /// 13 | /// Logger which doesn't log any information anywhere. 14 | /// 15 | public sealed class NullLogger : ILogger 16 | { 17 | /// 18 | /// As with all logging calls on this logger, this method is a no-op. 19 | /// 20 | public void Debug(string message) 21 | { 22 | } 23 | 24 | /// 25 | /// As with all logging calls on this logger, this method is a no-op. 26 | /// 27 | public void Debug(string format, params object[] formatArgs) 28 | { 29 | } 30 | 31 | /// 32 | /// As with all logging calls on this logger, this method is a no-op. 33 | /// 34 | public void Error(string message) 35 | { 36 | } 37 | 38 | /// 39 | /// As with all logging calls on this logger, this method is a no-op. 40 | /// 41 | public void Error(Exception exception, string message) 42 | { 43 | } 44 | 45 | /// 46 | /// As with all logging calls on this logger, this method is a no-op. 47 | /// 48 | public void Error(string format, params object[] formatArgs) 49 | { 50 | } 51 | 52 | /// 53 | /// Returns a reference to the instance on which the method is called, as 54 | /// instances aren't associated with specific types. 55 | /// 56 | /// 57 | public ILogger ForType() 58 | { 59 | return this; 60 | } 61 | 62 | /// 63 | /// As with all logging calls on this logger, this method is a no-op. 64 | /// 65 | public void Info(string message) 66 | { 67 | } 68 | 69 | /// 70 | /// As with all logging calls on this logger, this method is a no-op. 71 | /// 72 | public void Info(string format, params object[] formatArgs) 73 | { 74 | } 75 | 76 | /// 77 | /// As with all logging calls on this logger, this method is a no-op. 78 | /// 79 | public void Warning(string message) 80 | { 81 | } 82 | 83 | /// 84 | /// As with all logging calls on this logger, this method is a no-op. 85 | /// 86 | public void Warning(Exception exception, string message) 87 | { 88 | } 89 | 90 | /// 91 | /// As with all logging calls on this logger, this method is a no-op. 92 | /// 93 | public void Warning(string format, params object[] formatArgs) 94 | { 95 | } 96 | } 97 | } 98 | -------------------------------------------------------------------------------- /src/GroupCache/IGroupCacheClient.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | using System.IO; 12 | using System.Runtime.Serialization; 13 | using System.Threading; 14 | using System.Threading.Tasks; 15 | 16 | public interface IGroupCacheClient : IDisposable 17 | { 18 | Task GetAsync(string group, string key, Stream sink, ICacheControl cacheControl, CancellationToken ct); 19 | 20 | PeerEndpoint Endpoint { get; } 21 | 22 | /// 23 | /// Gets a value indicating whether this is true if this client is not making a request to a remote machine but simply read from local cache. 24 | /// 25 | bool IsLocal { get; } 26 | } 27 | 28 | [Serializable] 29 | public class InternalServerErrorException : Exception 30 | { 31 | public InternalServerErrorException(string message) 32 | : base(message) 33 | { 34 | } 35 | 36 | public InternalServerErrorException(string message, Exception innerException) 37 | : base(message, innerException) 38 | { 39 | } 40 | 41 | protected InternalServerErrorException(SerializationInfo info, StreamingContext context) 42 | : base(info, context) 43 | { 44 | } 45 | } 46 | 47 | [Serializable] 48 | public class ConnectFailureException : Exception 49 | { 50 | public ConnectFailureException() 51 | { 52 | } 53 | 54 | public ConnectFailureException(string message) 55 | : base(message) 56 | { 57 | } 58 | 59 | public ConnectFailureException(string message, Exception innerException) 60 | : base(message, innerException) 61 | { 62 | } 63 | 64 | protected ConnectFailureException(SerializationInfo info, StreamingContext context) 65 | : base(info, context) 66 | { 67 | } 68 | } 69 | 70 | [Serializable] 71 | public class ServerBusyException : Exception 72 | { 73 | public ServerBusyException() 74 | { 75 | } 76 | 77 | public ServerBusyException(string message) 78 | : base(message) 79 | { 80 | } 81 | } 82 | 83 | [Serializable] 84 | public class GroupNotFoundException : Exception 85 | { 86 | public GroupNotFoundException() 87 | { 88 | } 89 | 90 | public GroupNotFoundException(string message) 91 | : base(message) 92 | { 93 | } 94 | 95 | public GroupNotFoundException(string message, Exception innerException) 96 | : base(message, innerException) 97 | { 98 | } 99 | 100 | protected GroupNotFoundException(SerializationInfo info, StreamingContext context) 101 | : base(info, context) 102 | { 103 | } 104 | } 105 | } 106 | -------------------------------------------------------------------------------- /src/GroupCache/SimpleRetryPolicy.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | using System.Linq; 12 | using System.Threading; 13 | using System.Threading.Tasks; 14 | 15 | public class SimpleRetryPolicy 16 | { 17 | public const int DEFAULTMAXATTEMPTS = 3; 18 | public static readonly TimeSpan DEFAULTBACKOFFPERIOD = TimeSpan.FromMilliseconds(1000); 19 | private volatile int maxAttempts; 20 | private volatile int backOffPeriod; 21 | private readonly Type[] retryableExceptionTypes; 22 | 23 | public SimpleRetryPolicy() 24 | : this(DEFAULTMAXATTEMPTS, DEFAULTBACKOFFPERIOD) 25 | { 26 | } 27 | 28 | public SimpleRetryPolicy(int maxAttempts, TimeSpan backOffPeriod) 29 | : this(maxAttempts, backOffPeriod, new Type[] { typeof(Exception) }) 30 | { 31 | } 32 | 33 | public SimpleRetryPolicy(int maxAttempts, TimeSpan backOffPeriod, Type[] retryableExceptions) 34 | { 35 | this.maxAttempts = maxAttempts; 36 | this.backOffPeriod = (int)backOffPeriod.TotalMilliseconds; 37 | this.retryableExceptionTypes = retryableExceptions; 38 | } 39 | 40 | private bool RetryForException(Exception classifiable) 41 | { 42 | if (classifiable == null) 43 | { 44 | return false; 45 | } 46 | 47 | var exceptionClass = classifiable.GetType(); 48 | 49 | if (this.retryableExceptionTypes == null) 50 | { 51 | return false; 52 | } 53 | else 54 | { 55 | // Determines whether the exception is a subclass of any element of the retryable exception type. 56 | return this.retryableExceptionTypes.Any((retryableType) => { return retryableType.IsAssignableFrom(exceptionClass); }); 57 | } 58 | } 59 | 60 | /// 61 | /// Gets or sets the maximum retry count. 62 | /// 63 | /// The maximum retry count. 64 | public int MaxAttempts 65 | { 66 | get { return this.maxAttempts; } 67 | set { this.maxAttempts = value; } 68 | } 69 | 70 | /// 71 | /// Gets or sets the delay time span to sleep after an exception is thrown and a rety is 72 | /// attempted. 73 | /// 74 | /// The delay time span. 75 | public TimeSpan BackOffPeriod 76 | { 77 | get { return TimeSpan.FromMilliseconds(this.backOffPeriod); } 78 | set { this.backOffPeriod = (int)value.TotalMilliseconds; } 79 | } 80 | 81 | public virtual bool CanRetry(RetryContext context) 82 | { 83 | Exception ex = context.LastException; 84 | 85 | // N.B. the contract is defined to include the initial attempt in the count. 86 | return (ex == null || this.RetryForException(ex)) && (context.RetryCount < this.maxAttempts); 87 | } 88 | 89 | public virtual void RegisterThrowable(RetryContext context, Exception exception) 90 | { 91 | context.RegisterException(exception); 92 | } 93 | 94 | public virtual void BackOff(RetryContext context) 95 | { 96 | Thread.Sleep(this.BackOffPeriod); 97 | } 98 | 99 | public virtual Task BackOffAsync(RetryContext context) 100 | { 101 | return Task.Delay(this.BackOffPeriod); 102 | } 103 | 104 | public virtual T HandleRetryExhausted(RetryContext context) 105 | { 106 | throw new ExhaustedRetryException("Retry exhausted after last attempt with no recovery path.", context.LastException); 107 | } 108 | } 109 | } -------------------------------------------------------------------------------- /src/GroupCache/SemaphoreHolder.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | using System.Threading; 12 | using System.Threading.Tasks; 13 | 14 | public static class SemaphoreExtensions 15 | { 16 | private const string TimeOutError = "Failed to Aquire lock within timeout"; 17 | 18 | public static SemaphoreHolder Acquire(this SemaphoreSlim semaphore) 19 | { 20 | semaphore.Wait(); 21 | return new SemaphoreHolder(semaphore); 22 | } 23 | 24 | public static SemaphoreHolder Acquire(this SemaphoreSlim semaphore, CancellationToken cancellationToken) 25 | { 26 | semaphore.Wait(cancellationToken); 27 | return new SemaphoreHolder(semaphore); 28 | } 29 | 30 | public static SemaphoreHolder Acquire(this SemaphoreSlim semaphore, TimeSpan timeout) 31 | { 32 | if (!semaphore.Wait(timeout)) 33 | { 34 | throw new TimeoutException(TimeOutError); 35 | } 36 | 37 | return new SemaphoreHolder(semaphore); 38 | } 39 | 40 | public static SemaphoreHolder Acquire(this SemaphoreSlim semaphore, TimeSpan timeout, CancellationToken cancellationToken) 41 | { 42 | if (!semaphore.Wait(timeout, cancellationToken)) 43 | { 44 | throw new TimeoutException(TimeOutError); 45 | } 46 | 47 | return new SemaphoreHolder(semaphore); 48 | } 49 | 50 | public static async Task AcquireAsync(this SemaphoreSlim semaphore) 51 | { 52 | await semaphore.WaitAsync().ConfigureAwait(false); 53 | return new SemaphoreHolder(semaphore); 54 | } 55 | 56 | public static async Task AcquireAsync(this SemaphoreSlim semaphore, CancellationToken cancellationToken) 57 | { 58 | await semaphore.WaitAsync(cancellationToken).ConfigureAwait(false); 59 | return new SemaphoreHolder(semaphore); 60 | } 61 | 62 | public static async Task AcquireAsync(this SemaphoreSlim semaphore, TimeSpan timeout) 63 | { 64 | if (!await semaphore.WaitAsync(timeout).ConfigureAwait(false)) 65 | { 66 | throw new TimeoutException(TimeOutError); 67 | } 68 | 69 | return new SemaphoreHolder(semaphore); 70 | } 71 | 72 | public static async Task AcquireAsync(this SemaphoreSlim semaphore, TimeSpan timeout, CancellationToken cancellationToken) 73 | { 74 | if (!await semaphore.WaitAsync(timeout, cancellationToken).ConfigureAwait(false)) 75 | { 76 | throw new TimeoutException(TimeOutError); 77 | } 78 | 79 | return new SemaphoreHolder(semaphore); 80 | } 81 | } 82 | 83 | /// 84 | /// Helper class that makes it easier to ensure proper usage of a for 85 | /// readers by providing support for and the using keyword. 86 | /// 87 | public sealed class SemaphoreHolder : IDisposable 88 | { 89 | private readonly SemaphoreSlim semaphore; 90 | 91 | // Track whether Dispose has been called. 92 | private bool disposed = false; 93 | 94 | public SemaphoreHolder(SemaphoreSlim semaphore) 95 | { 96 | Argument.NotNull(semaphore, "semaphore"); 97 | this.semaphore = semaphore; 98 | } 99 | 100 | public void Dispose() 101 | { 102 | this.Dispose(true); 103 | } 104 | 105 | private void Dispose(bool disposing) 106 | { 107 | if (disposing && !this.disposed) 108 | { 109 | this.semaphore.Release(); 110 | this.disposed = true; 111 | } 112 | } 113 | } 114 | } 115 | -------------------------------------------------------------------------------- /src/GroupCacheStubImpl/OwinClient.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCacheStub 9 | { 10 | using System; 11 | using System.Collections.Generic; 12 | using System.IO; 13 | using System.Net; 14 | using System.Net.Http; 15 | using System.Threading; 16 | using System.Threading.Tasks; 17 | using GroupCache; 18 | 19 | public class OwinClient : IGroupCacheClient, IDisposable 20 | { 21 | private readonly HttpClient client; 22 | 23 | /// 24 | public PeerEndpoint Endpoint { get; private set; } 25 | 26 | /// 27 | public bool IsLocal 28 | { 29 | get { return false; } 30 | } 31 | 32 | public OwinClient(PeerEndpoint endpoint, int minuteTimeout = 2) 33 | { 34 | this.Endpoint = endpoint; 35 | this.client = new HttpClient() 36 | { 37 | Timeout = TimeSpan.FromMinutes(minuteTimeout), 38 | BaseAddress = new UriBuilder("http", this.Endpoint.HostName, this.Endpoint.Port).Uri, 39 | }; 40 | this.client.DefaultRequestHeaders.ConnectionClose = true; 41 | } 42 | 43 | /// 44 | public async Task GetAsync(string group, string key, Stream sink, ICacheControl cacheControl, CancellationToken ct) 45 | { 46 | var formContent = new FormUrlEncodedContent(new[] 47 | { 48 | new KeyValuePair(OwinServer.GROUPNAME, group), 49 | new KeyValuePair(OwinServer.KEY, key), 50 | }); 51 | 52 | HttpRequestMessage msg = new HttpRequestMessage(HttpMethod.Post, "Get") 53 | { 54 | Content = formContent, 55 | Version = HttpVersion.Version10, 56 | }; 57 | 58 | // GetAsync block until the response’s (headers + content) is fully downloaded/read to the memory 59 | // Unless we use HttpCompletionOption.ResponseHeadersRead 60 | HttpResponseMessage response; 61 | try 62 | { 63 | response = await this.client.SendAsync(msg, HttpCompletionOption.ResponseHeadersRead, ct).ConfigureAwait(false); 64 | } 65 | catch (HttpRequestException ex) 66 | { 67 | throw new ConnectFailureException($"fail to send request to {this.Endpoint.ToString()}", ex); 68 | } 69 | 70 | using (response) 71 | { 72 | if (!response.IsSuccessStatusCode) 73 | { 74 | if (response.StatusCode == HttpStatusCode.InternalServerError) 75 | { 76 | throw new InternalServerErrorException(response.ReasonPhrase); 77 | } 78 | 79 | if (response.StatusCode == HttpStatusCode.ServiceUnavailable) 80 | { 81 | throw new ServerBusyException(response.ReasonPhrase); 82 | } 83 | 84 | if (response.StatusCode == HttpStatusCode.NotFound) 85 | { 86 | throw new GroupNotFoundException(response.ReasonPhrase); 87 | } 88 | 89 | response.EnsureSuccessStatusCode(); 90 | } 91 | 92 | // if we reach her we can safely read response.Content 93 | if (response.Content == null) 94 | { 95 | throw new InternalServerErrorException("response body is null"); 96 | } 97 | 98 | if (response.Headers.CacheControl != null && response.Headers.CacheControl.NoStore) 99 | { 100 | cacheControl.NoStore = true; 101 | } 102 | 103 | // using ct.Register to force CopyToAsync to return early and throw OperationCanceledException 104 | using (ct.Register(response.Dispose)) 105 | { 106 | try 107 | { 108 | await response.Content.CopyToAsync(sink).ConfigureAwait(false); 109 | } 110 | catch (ObjectDisposedException e) when (ct.IsCancellationRequested) 111 | { 112 | throw new OperationCanceledException(null, e, ct); 113 | } 114 | } 115 | } 116 | } 117 | 118 | /// 119 | public void Dispose() 120 | { 121 | this.client.Dispose(); 122 | } 123 | } 124 | } 125 | -------------------------------------------------------------------------------- /src/GroupCache/MemoryCache.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | using System.Collections.Generic; 12 | using System.IO; 13 | using System.Threading; 14 | using System.Threading.Tasks; 15 | 16 | public sealed class MemoryCacheEntry : ICacheEntry 17 | { 18 | private ArraySegment segment; 19 | 20 | public MemoryCacheEntry(ArraySegment segment) 21 | { 22 | this.segment = segment; 23 | } 24 | 25 | /// 26 | public Task DisposeAsync() 27 | { 28 | return Task.CompletedTask; 29 | } 30 | 31 | /// 32 | public void Ref() 33 | { 34 | } 35 | 36 | /// 37 | public Stream Value() 38 | { 39 | return new MemoryStream(this.segment.Array, this.segment.Offset, this.segment.Count); 40 | } 41 | } 42 | 43 | public sealed class MemoryCache : ICache 44 | { 45 | private const int DefaultCopyBufferSize = 81920; 46 | private readonly SingleFlight createEntry = new SingleFlight(); 47 | private readonly LRUCache> cache; 48 | 49 | public MemoryCache(int maxItemCount, TimeSpan ttl) 50 | { 51 | this.cache = new LRUCache>(maxItemCount, ttl); 52 | this.cache.ItemOverCapacity += this.TriggerItemCapacity; 53 | } 54 | 55 | public MemoryCache(int maxItemCount = 200, ulong capacity = 0) 56 | { 57 | this.cache = new LRUCache>(maxItemCount, capacity); 58 | this.cache.ItemOverCapacity += this.TriggerItemCapacity; 59 | } 60 | 61 | public MemoryCache(int maxItemCount, ulong capacity, TimeSpan ttl) 62 | { 63 | this.cache = new LRUCache>(maxItemCount, EqualityComparer.Default, capacity, ttl); 64 | this.cache.ItemOverCapacity += this.TriggerItemCapacity; 65 | } 66 | 67 | /// 68 | public event Action ItemOverCapacity; 69 | 70 | /// valueFactory 71 | /// Get item from cache of call valueFactory if missing. 72 | /// 73 | /// The key of the value that need to be filled in. 74 | /// valueFactory should write result to the stream but not close it. 75 | /// Cancellation token. 76 | /// A representing the asynchronous operation. 77 | public Task GetOrAddAsync(string key, Func valueFactory, ICacheControl cacheControl, CancellationToken ct) 78 | { 79 | return this.createEntry.DoAsync(key, async () => 80 | { 81 | ICacheEntry found = await this.GetAsync(key, ct).ConfigureAwait(false); 82 | if (!(found is EmptyCacheEntry)) 83 | { 84 | return found; 85 | } 86 | 87 | ArraySegment buffer; 88 | using (var memStream = new MemoryStream()) 89 | { 90 | await valueFactory(key, memStream, cacheControl).ConfigureAwait(false); 91 | memStream.Position = 0; 92 | buffer = new ArraySegment(memStream.ToArray()); 93 | } 94 | 95 | if (!cacheControl.NoStore) 96 | { 97 | this.cache.Add(key, buffer, (ulong)buffer.Count); 98 | } 99 | 100 | return new MemoryCacheEntry(buffer); 101 | }); 102 | } 103 | 104 | public Task GetAsync(string key, CancellationToken ct) 105 | { 106 | var found = this.cache.TryGetValue(key, out ArraySegment bytes); 107 | if (!found) 108 | { 109 | return Task.FromResult(new EmptyCacheEntry()); 110 | } 111 | 112 | return Task.FromResult(new MemoryCacheEntry(bytes)); 113 | } 114 | 115 | private void TriggerItemCapacity(KeyValuePair> kv) 116 | { 117 | this.ItemOverCapacity?.Invoke(kv.Key); 118 | } 119 | 120 | /// 121 | public Task RemoveAsync(string key, CancellationToken ct) 122 | { 123 | this.cache.Remove(key); 124 | return Task.CompletedTask; 125 | } 126 | } 127 | } 128 | -------------------------------------------------------------------------------- /src/GroupCacheStubImpl/OwinServer.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCacheStub 9 | { 10 | using System; 11 | using System.Linq; 12 | using GroupCache; 13 | using Microsoft.Owin; 14 | using Microsoft.Owin.Hosting; 15 | using Owin; 16 | 17 | public class OwinServer : IDisposable 18 | { 19 | public const string GROUPNAME = "groupName"; 20 | public const string KEY = "key"; 21 | private const string BASEURL = "/"; 22 | private IDisposable server; 23 | private readonly IGroupCacheClient handler; 24 | private readonly string host; 25 | 26 | // Admin rights are not needed for port values of 5000 and higher 27 | private readonly int port; 28 | 29 | /// 30 | /// Initializes a new instance of the class. 31 | /// Creates a new server. 32 | /// 33 | /// the host. 34 | /// the port. If zero, an unused port is chosen automatically. 35 | public OwinServer(IGroupCacheClient handler, int port, string host = "*") 36 | { 37 | this.host = host; 38 | this.port = port; 39 | this.handler = handler; 40 | } 41 | 42 | public void Start() 43 | { 44 | var baseUrl = new UriBuilder("http", this.host, this.port).ToString(); 45 | var startOption = new StartOptions(baseUrl) { ServerFactory = "Microsoft.Owin.Host.HttpListener" }; 46 | 47 | // WebApp class is from Microsoft.Owin.Hosting 48 | this.server = WebApp.Start(startOption, this.Configuration); 49 | } 50 | 51 | public void Dispose() 52 | { 53 | if (this.server != null) 54 | { 55 | this.server.Dispose(); 56 | } 57 | } 58 | 59 | public void Configuration(IAppBuilder app) 60 | { 61 | app.Run(async context => 62 | { 63 | var request = context.Request; 64 | var response = context.Response; 65 | var callCancelled = context.Request.CallCancelled; 66 | 67 | var form = await request.ReadFormAsync(); 68 | var groupName = form.Get(GROUPNAME); 69 | var key = form.Get(KEY); 70 | 71 | if (groupName == null || key == null) 72 | { 73 | response.StatusCode = 400; // BadRequest; 74 | return; 75 | } 76 | 77 | response.ContentType = "application/octet-stream"; 78 | try 79 | { 80 | var cacheControl = new OwinCacheControl(context.Response.Headers); 81 | await this.handler.GetAsync(groupName, key, response.Body, cacheControl, callCancelled); 82 | } 83 | catch (GroupNotFoundException ex) 84 | { 85 | response.StatusCode = 404; 86 | response.ReasonPhrase = ex.ToString(); 87 | } 88 | catch (ServerBusyException busy) 89 | { 90 | response.StatusCode = 503; 91 | response.ReasonPhrase = busy.ToString(); 92 | } 93 | catch (Exception ex) 94 | { 95 | response.StatusCode = 500; 96 | response.ReasonPhrase = ex.ToString(); 97 | } 98 | }); 99 | } 100 | } 101 | 102 | public class OwinCacheControl : ICacheControl 103 | { 104 | private const string CacheControlHeaderName = "Cache-Control"; 105 | private const string NoStoreHeaderValue = "no-store"; 106 | private readonly IHeaderDictionary headers; 107 | 108 | public OwinCacheControl(IHeaderDictionary headers) 109 | { 110 | this.headers = headers; 111 | } 112 | 113 | public bool NoStore 114 | { 115 | get 116 | { 117 | var values = this.headers.GetCommaSeparatedValues(CacheControlHeaderName); 118 | return values != null && values.Contains(NoStoreHeaderValue); 119 | } 120 | 121 | set 122 | { 123 | if (value == true) 124 | { 125 | this.headers.AppendCommaSeparatedValues(CacheControlHeaderName, new string[] { NoStoreHeaderValue }); 126 | } 127 | else 128 | { 129 | var values = this.headers.GetCommaSeparatedValues(CacheControlHeaderName); 130 | if (values != null) 131 | { 132 | var valuesMinusNoStore = values.Where((val) => val != NoStoreHeaderValue).ToArray(); 133 | this.headers.SetCommaSeparatedValues(CacheControlHeaderName, valuesMinusNoStore); 134 | } 135 | } 136 | } 137 | } 138 | } 139 | } 140 | -------------------------------------------------------------------------------- /src/GroupCacheStubImpl/OwinPool.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCacheStub 9 | { 10 | using System; 11 | using System.Collections.Concurrent; 12 | using System.Collections.Generic; 13 | using System.IO; 14 | using System.Threading; 15 | using System.Threading.Tasks; 16 | using GroupCache; 17 | 18 | /// 19 | /// OwinPool implements IPeerPicker for a pool of HTTP peers. 20 | /// 21 | public sealed class OwinPool : IGroupCacheClient, IDisposable 22 | { 23 | private readonly object @lock = new object(); 24 | private readonly OwinServer server; 25 | private PeerEndpoint self; 26 | private readonly ConcurrentDictionary> peerPickers = new ConcurrentDictionary>(StringComparer.InvariantCultureIgnoreCase); 27 | private readonly ConcurrentDictionary> cacheClients = new ConcurrentDictionary>(); 28 | private readonly SemaphoreSlim concurrencyLimiter = null; 29 | private readonly int concurrencyLimit; 30 | 31 | /// 32 | /// Initializes a new instance of the class. 33 | /// 34 | /// 35 | /// 36 | public OwinPool(PeerEndpoint self, int concurrencyLimit = 24) 37 | { 38 | this.self = self; 39 | this.concurrencyLimit = concurrencyLimit; 40 | this.concurrencyLimiter = new SemaphoreSlim(initialCount: this.concurrencyLimit); 41 | this.server = new OwinServer(this, self.Port, self.HostName); 42 | this.server.Start(); 43 | } 44 | 45 | /// 46 | public PeerEndpoint Endpoint 47 | { 48 | get { return this.self; } 49 | } 50 | 51 | /// 52 | public bool IsLocal 53 | { 54 | get { return true; } 55 | } 56 | 57 | /// 58 | /// Handle request from Peers and forward to the correct local Group instance. 59 | /// 60 | /// A representing the asynchronous operation. 61 | public async Task GetAsync(string groupName, string key, Stream sink, ICacheControl cacheControl, CancellationToken ct) 62 | { 63 | SemaphoreHolder limiter; 64 | try 65 | { 66 | limiter = await this.concurrencyLimiter.AcquireAsync(TimeSpan.Zero).ConfigureAwait(false); 67 | } 68 | catch (TimeoutException) 69 | { 70 | throw new ServerBusyException("Too many concurrent connection"); 71 | } 72 | 73 | using (limiter) 74 | { 75 | var groupKey = new GroupKey { GroupName = groupName, Endpoint = this.Endpoint }; 76 | var found = GroupCache.GetGroup(groupKey, out Group group); 77 | if (!found) 78 | { 79 | throw new GroupNotFoundException($"no such group: {groupName}"); 80 | } 81 | 82 | group.Stats.TraceConcurrentServerRequests(this.concurrencyLimit - this.concurrencyLimiter.CurrentCount); 83 | group.Stats.TraceServerRequests(groupName); 84 | 85 | // We received a request from a peer, we need to download it locally and not forward to peer 86 | // because forwarding to peer would cause infinite loop if using different peer list 87 | await group.GetAsyncLocallyAsync(key, sink, cacheControl, ct); 88 | } 89 | } 90 | 91 | public IGroupCacheClient GetClient(PeerEndpoint endpoint) 92 | { 93 | var lazy = new Lazy( 94 | () => 95 | { 96 | return new CircuitBreakerClient(new OwinClient(endpoint)); 97 | }, 98 | LazyThreadSafetyMode.ExecutionAndPublication); 99 | return this.cacheClients.GetOrAdd(endpoint, lazy).Value; 100 | } 101 | 102 | public IPeerPicker GetPicker(string groupName, IEqualityComparer keyHasher = null) 103 | { 104 | var lazy = new Lazy( 105 | () => 106 | { 107 | var hasher = keyHasher; 108 | if (hasher == null) 109 | { 110 | hasher = EqualityComparer.Default; 111 | } 112 | 113 | var pool = new OwinPoolPicker(groupName, this); 114 | pool.KeyHasher = hasher; 115 | return pool; 116 | }, 117 | LazyThreadSafetyMode.ExecutionAndPublication); 118 | return this.peerPickers.GetOrAdd(groupName, lazy).Value; 119 | } 120 | 121 | /// 122 | public void Dispose() 123 | { 124 | this.server.Dispose(); 125 | } 126 | } 127 | } 128 | -------------------------------------------------------------------------------- /src/GroupCacheStubImpl/OwinPoolPicker.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCacheStub 9 | { 10 | using System; 11 | using System.Collections.Generic; 12 | using System.Linq; 13 | using GroupCache; 14 | 15 | public class OwinPoolPicker : IPeerPicker 16 | { 17 | private readonly object @lock = new object(); 18 | private readonly OwinPool locaHandler; 19 | private readonly string groupName; 20 | private readonly JumpHasher consistentHasher = new JumpHasher(); 21 | private List peerEndpoints; 22 | private Dictionary clients; 23 | 24 | public IEqualityComparer KeyHasher { get; set; } = EqualityComparer.Default; 25 | 26 | public OwinPoolPicker(string groupName, OwinPool locaHandler) 27 | : this(groupName, locaHandler, new List()) 28 | { 29 | } 30 | 31 | public OwinPoolPicker(string groupName, OwinPool localHandler, List peerEndpoints) 32 | { 33 | this.groupName = groupName; 34 | this.locaHandler = localHandler; 35 | this.Set(peerEndpoints); 36 | } 37 | 38 | /// 39 | /// Gets endpoint metadata of the local machine. 40 | /// 41 | public PeerEndpoint Self 42 | { 43 | get 44 | { 45 | return this.locaHandler.Endpoint; 46 | } 47 | } 48 | 49 | /// 50 | public List PickPeers(string key, int numPeers) 51 | { 52 | lock (this.@lock) 53 | { 54 | numPeers = Math.Min(numPeers, this.peerEndpoints.Count); 55 | List replica = new List(numPeers); 56 | List buckets = new List(this.peerEndpoints); 57 | 58 | for (int i = 0; i < numPeers; i++) 59 | { 60 | var keyHash = this.KeyHasher.GetHashCode(key); 61 | var index = this.consistentHasher.Hash((ulong)keyHash, buckets.Count); 62 | replica.Add(this.clients[buckets[index]]); 63 | 64 | // Remove this node from buckets to guarantee its note added twice to replica list 65 | buckets.RemoveAt(index); 66 | } 67 | 68 | return replica; 69 | } 70 | } 71 | 72 | /// 73 | public void Set(List peerEndpoints) 74 | { 75 | if (peerEndpoints == null) 76 | { 77 | return; 78 | } 79 | 80 | lock (this.@lock) 81 | { 82 | this.peerEndpoints = new List(peerEndpoints); 83 | this.peerEndpoints.Sort(); 84 | var peerClients = new Dictionary(); 85 | foreach (var peerEndpoint in this.peerEndpoints) 86 | { 87 | if (this.Self == peerEndpoint) 88 | { 89 | peerClients.Add(peerEndpoint, this.locaHandler); 90 | } 91 | else 92 | { 93 | var client = this.locaHandler.GetClient(peerEndpoint); 94 | peerClients.Add(peerEndpoint, client); 95 | } 96 | } 97 | 98 | this.clients = peerClients; 99 | } 100 | } 101 | 102 | /// 103 | public void Add(List peerEndpoints) 104 | { 105 | lock (this.@lock) 106 | { 107 | HashSet peerSet = new HashSet(this.peerEndpoints); 108 | peerSet.UnionWith(peerEndpoints); 109 | var newList = peerSet.ToList(); 110 | newList.Sort(); 111 | this.peerEndpoints = newList; 112 | var peerClients = new Dictionary(); 113 | foreach (var peerEndpoint in this.peerEndpoints) 114 | { 115 | bool isSelf = this.Self == peerEndpoint; 116 | if (isSelf) 117 | { 118 | peerClients.Add(peerEndpoint, this.locaHandler); 119 | } 120 | else 121 | { 122 | var client = this.locaHandler.GetClient(peerEndpoint); 123 | peerClients.Add(peerEndpoint, client); 124 | } 125 | } 126 | 127 | this.clients = peerClients; 128 | } 129 | } 130 | 131 | /// 132 | public int Count 133 | { 134 | get 135 | { 136 | lock (this.@lock) 137 | { 138 | return this.peerEndpoints.Count; 139 | } 140 | } 141 | } 142 | } 143 | } 144 | -------------------------------------------------------------------------------- /src/GroupCache/Retry.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | using System.Threading.Tasks; 12 | 13 | /// 14 | /// Template class that simplifies the execution of operations with retry semantics. 15 | /// This class is thread-safe and suitable for concurrent access when executing operations and when performing configuration changes. 16 | /// 17 | public class Retry 18 | { 19 | private readonly SimpleRetryPolicy retryPolicy; 20 | 21 | public Action OnRetry 22 | { 23 | get; 24 | set; 25 | } 26 | 27 | /// 28 | /// Initializes a new instance of the class. 29 | /// 30 | /// 31 | public Retry(SimpleRetryPolicy retryPolicy) 32 | { 33 | this.OnRetry = null; 34 | this.retryPolicy = retryPolicy; 35 | } 36 | 37 | /// 38 | /// Keep executing the callback until it eiether succeeds or the policy dictates that we stop, 39 | /// in which case the most recent exception thrown by the callback will be rethrown. 40 | /// 41 | /// lambda for an operation that can be retried. 42 | public void Execute(Action action) 43 | { 44 | this.Execute((context) => 45 | { 46 | action(context); 47 | return true; 48 | }); 49 | } 50 | 51 | /// 52 | /// Keep executing the callback until it eiether succeeds or the policy dictates that we stop, 53 | /// in which case the most recent exception thrown by the callback will be rethrown. 54 | /// 55 | /// Callback interface for an operation that can be retried. 56 | /// Return value of the callback. 57 | /// Return type. 58 | public T Execute(Func callback) 59 | { 60 | Exception lastException = null; 61 | RetryContext context = new RetryContext(this.retryPolicy.MaxAttempts, this.retryPolicy.BackOffPeriod); 62 | while (this.retryPolicy.CanRetry(context) && !context.IsExhausted) 63 | { 64 | try 65 | { 66 | lastException = null; 67 | return callback(context); 68 | } 69 | catch (Exception ex) 70 | { 71 | lastException = ex; 72 | this.retryPolicy.RegisterThrowable(context, ex); 73 | 74 | if (!this.retryPolicy.CanRetry(context)) 75 | { 76 | // Rethrow last exception 77 | throw; 78 | } 79 | } 80 | 81 | var onRetryHandler = this.OnRetry; 82 | if (onRetryHandler != null) 83 | { 84 | onRetryHandler(context); 85 | } 86 | 87 | this.retryPolicy.BackOff(context); 88 | } 89 | 90 | return this.retryPolicy.HandleRetryExhausted(context); 91 | } 92 | 93 | /// 94 | /// Keep executing the callback until it eiether succeeds or the policy dictates that we stop, 95 | /// in which case the most recent exception thrown by the callback will be rethrown. 96 | /// 97 | /// lambda for an operation that can be retried. 98 | /// A representing the asynchronous operation. 99 | public Task ExecuteAsync(Func func) 100 | { 101 | return this.ExecuteAsync(async (context) => 102 | { 103 | await func(context).ConfigureAwait(false); 104 | return true; 105 | }); 106 | } 107 | 108 | /// 109 | /// Keep executing the callback until it eiether succeeds or the policy dictates that we stop, 110 | /// in which case the most recent exception thrown by the callback will be rethrown. 111 | /// 112 | /// Callback interface for an operation that can be retried. 113 | /// Return value of the callback. 114 | /// Return type. 115 | public async Task ExecuteAsync(Func> callback) 116 | { 117 | Exception lastException = null; 118 | RetryContext context = new RetryContext(this.retryPolicy.MaxAttempts, this.retryPolicy.BackOffPeriod); 119 | while (this.retryPolicy.CanRetry(context) && !context.IsExhausted) 120 | { 121 | try 122 | { 123 | lastException = null; 124 | return await callback(context).ConfigureAwait(false); 125 | } 126 | catch (Exception ex) 127 | { 128 | lastException = ex; 129 | this.retryPolicy.RegisterThrowable(context, ex); 130 | 131 | if (!this.retryPolicy.CanRetry(context)) 132 | { 133 | // Rethrow last exception 134 | throw; 135 | } 136 | } 137 | 138 | var onRetryHandler = this.OnRetry; 139 | if (onRetryHandler != null) 140 | { 141 | onRetryHandler(context); 142 | } 143 | 144 | await this.retryPolicy.BackOffAsync(context).ConfigureAwait(false); 145 | } 146 | 147 | return this.retryPolicy.HandleRetryExhausted(context); 148 | } 149 | } 150 | } -------------------------------------------------------------------------------- /src/GroupCache/IPeerPicker.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | using System.Collections.Generic; 12 | 13 | /// 14 | /// PeerPicker is the interface that must be implemented to locate 15 | /// the peer that owns a specific key. 16 | /// 17 | public interface IPeerPicker 18 | { 19 | /// 20 | /// PickPeer returns the peer that owns the specific key. 21 | /// Property IsLocal on IGroupCacheClient will be false 22 | /// to indicate that a remote peer was nominated. 23 | /// 24 | /// 25 | List PickPeers(string key, int numPeers); 26 | 27 | /// 28 | /// Set the peer list this picker need to select from. 29 | /// 30 | /// List peer Endpoint struct. 31 | void Set(List peerEndpoints); 32 | 33 | /// 34 | /// Set the peer list to the union of the existing list and the provided list. 35 | /// 36 | /// List of peer to add if not already present. 37 | void Add(List peerEndpoints); 38 | 39 | /// 40 | /// Gets endpoint metadata of the local machine. 41 | /// 42 | PeerEndpoint Self { get; } 43 | 44 | /// 45 | /// Gets the total number of peer this PeerPicker select from. 46 | /// 47 | int Count { get; } 48 | } 49 | 50 | public struct PeerEndpoint : IEquatable, IComparable 51 | { 52 | private string hostName; 53 | 54 | public string HostName 55 | { 56 | get 57 | { 58 | return this.hostName; 59 | } 60 | 61 | set 62 | { 63 | this.hostName = value.ToLower(); 64 | } 65 | } 66 | 67 | public int Port { get; set; } 68 | 69 | public override bool Equals(object obj) 70 | { 71 | return obj is PeerEndpoint && this.Equals((PeerEndpoint)obj); 72 | } 73 | 74 | public bool Equals(PeerEndpoint other) 75 | { 76 | return this.HostName.Equals(other.HostName, StringComparison.OrdinalIgnoreCase) && 77 | this.Port == other.Port; 78 | } 79 | 80 | public override int GetHashCode() 81 | { 82 | var hashCode = 1180852050; 83 | hashCode = (hashCode * -1521134295) + base.GetHashCode(); 84 | hashCode = (hashCode * -1521134295) + EqualityComparer.Default.GetHashCode(this.HostName); 85 | hashCode = (hashCode * -1521134295) + this.Port.GetHashCode(); 86 | return hashCode; 87 | } 88 | 89 | public static bool operator ==(PeerEndpoint endpoint1, PeerEndpoint endpoint2) 90 | { 91 | return endpoint1.Equals(endpoint2); 92 | } 93 | 94 | public static bool operator !=(PeerEndpoint endpoint1, PeerEndpoint endpoint2) 95 | { 96 | return !endpoint1.Equals(endpoint2); 97 | } 98 | 99 | public static bool operator <=(PeerEndpoint endpoint1, PeerEndpoint endpoint2) 100 | { 101 | return endpoint1.CompareTo(endpoint2) <= 0; 102 | } 103 | 104 | public static bool operator >=(PeerEndpoint endpoint1, PeerEndpoint endpoint2) 105 | { 106 | return endpoint1.CompareTo(endpoint2) >= 0; 107 | } 108 | 109 | public static bool operator <(PeerEndpoint endpoint1, PeerEndpoint endpoint2) 110 | { 111 | return endpoint1.CompareTo(endpoint2) < 0; 112 | } 113 | 114 | public static bool operator >(PeerEndpoint endpoint1, PeerEndpoint endpoint2) 115 | { 116 | return endpoint1.CompareTo(endpoint2) > 0; 117 | } 118 | 119 | public static bool TryCreate(string endPointStr, out PeerEndpoint endpoint) 120 | { 121 | bool canParse = Uri.TryCreate($"http://{endPointStr}", UriKind.Absolute, out Uri uri); 122 | if (!canParse) 123 | { 124 | endpoint = default(PeerEndpoint); 125 | return false; 126 | } 127 | 128 | endpoint = new PeerEndpoint { HostName = uri.Host, Port = uri.Port }; 129 | return true; 130 | } 131 | 132 | public int CompareTo(PeerEndpoint other) 133 | { 134 | return this.HostName.CompareTo(other.HostName); 135 | } 136 | 137 | public override string ToString() 138 | { 139 | return $"{this.hostName}:{this.Port}"; 140 | } 141 | } 142 | 143 | /// 144 | /// Key to uniquely identify a cache on local machine. 145 | /// this include the cache name and the endpoint metadata. 146 | /// 147 | public struct GroupKey : IEquatable 148 | { 149 | public string GroupName; 150 | public PeerEndpoint Endpoint; 151 | 152 | public override bool Equals(object obj) 153 | { 154 | return obj is GroupKey && this.Equals((GroupKey)obj); 155 | } 156 | 157 | public bool Equals(GroupKey other) 158 | { 159 | return this.GroupName == other.GroupName && 160 | this.Endpoint.Equals(other.Endpoint); 161 | } 162 | 163 | public override int GetHashCode() 164 | { 165 | var hashCode = -1870784389; 166 | hashCode = (hashCode * -1521134295) + base.GetHashCode(); 167 | hashCode = (hashCode * -1521134295) + EqualityComparer.Default.GetHashCode(this.GroupName); 168 | hashCode = (hashCode * -1521134295) + EqualityComparer.Default.GetHashCode(this.Endpoint); 169 | return hashCode; 170 | } 171 | 172 | public static bool operator ==(GroupKey key1, GroupKey key2) 173 | { 174 | return key1.Equals(key2); 175 | } 176 | 177 | public static bool operator !=(GroupKey key1, GroupKey key2) 178 | { 179 | return !(key1 == key2); 180 | } 181 | } 182 | } 183 | -------------------------------------------------------------------------------- /.editorconfig: -------------------------------------------------------------------------------- 1 | # Top-most EditorConfig file 2 | root = true 3 | 4 | # Global settings (applies to all files) 5 | [*] 6 | charset = utf-8 7 | end_of_line = crlf 8 | insert_final_newline = true 9 | indent_style = space 10 | indent_size = 4 11 | trim_trailing_whitespace = true 12 | 13 | # C# files 14 | [*.cs] 15 | dotnet_sort_system_directives_first = true 16 | dotnet_style_qualification_for_field = false:suggestion 17 | dotnet_style_qualification_for_property = false:suggestion 18 | dotnet_style_qualification_for_method = false:suggestion 19 | dotnet_style_qualification_for_event = false:suggestion 20 | dotnet_style_prefer_inferred_tuple_names = true:suggestion 21 | dotnet_style_prefer_inferred_anonymous_type_member_names = true:suggestion 22 | dotnet_style_prefer_auto_properties = true:suggestion 23 | dotnet_style_prefer_is_null_check_over_reference_equality_method = true:suggestion 24 | csharp_new_line_before_open_brace = all 25 | csharp_indent_case_contents = true 26 | csharp_indent_switch_labels = true 27 | csharp_prefer_braces = true:suggestion 28 | csharp_style_var_for_built_in_types = true:suggestion 29 | csharp_style_var_when_type_is_apparent = true:suggestion 30 | csharp_style_var_elsewhere = false:suggestion 31 | csharp_style_prefer_switch_expression = true:suggestion 32 | csharp_style_prefer_pattern_matching = true:suggestion 33 | csharp_style_prefer_throw_expression = true:suggestion 34 | csharp_style_prefer_conditional_delegate_call = true:suggestion 35 | csharp_using_directive_placement = inside_namespace:suggestion 36 | 37 | # Header template for team 38 | [*.cs] 39 | csharp_prefer_simple_using_statement = true:suggestion 40 | csharp_style_namespace_declarations = block_scoped:silent 41 | csharp_style_prefer_method_group_conversion = true:silent 42 | csharp_style_prefer_top_level_statements = true:silent 43 | csharp_style_prefer_primary_constructors = true:suggestion 44 | csharp_prefer_system_threading_lock = true:suggestion 45 | csharp_style_expression_bodied_methods = false:silent 46 | csharp_style_expression_bodied_constructors = false:silent 47 | csharp_style_expression_bodied_operators = false:silent 48 | csharp_style_expression_bodied_properties = true:silent 49 | csharp_style_expression_bodied_indexers = true:silent 50 | csharp_style_expression_bodied_accessors = true:silent 51 | csharp_style_expression_bodied_lambdas = true:silent 52 | csharp_style_expression_bodied_local_functions = false:silent 53 | csharp_indent_labels = one_less_than_current 54 | csharp_style_throw_expression = true:suggestion 55 | csharp_style_prefer_null_check_over_type_check = true:suggestion 56 | csharp_prefer_simple_default_expression = true:suggestion 57 | csharp_style_prefer_local_over_anonymous_function = true:suggestion 58 | csharp_style_prefer_index_operator = true:suggestion 59 | csharp_style_prefer_range_operator = true:suggestion 60 | csharp_style_implicit_object_creation_when_type_is_apparent = true:suggestion 61 | csharp_style_prefer_tuple_swap = true:suggestion 62 | csharp_style_prefer_unbound_generic_type_in_nameof = true:suggestion 63 | csharp_style_prefer_utf8_string_literals = true:suggestion 64 | csharp_style_inlined_variable_declaration = true:suggestion 65 | csharp_style_deconstructed_variable_declaration = true:suggestion 66 | csharp_style_unused_value_assignment_preference = discard_variable:suggestion 67 | csharp_style_unused_value_expression_statement_preference = discard_variable:silent 68 | 69 | [*.{cs,vb}] 70 | #### Naming styles #### 71 | 72 | # Naming rules 73 | 74 | dotnet_naming_rule.interface_should_be_begins_with_i.severity = suggestion 75 | dotnet_naming_rule.interface_should_be_begins_with_i.symbols = interface 76 | dotnet_naming_rule.interface_should_be_begins_with_i.style = begins_with_i 77 | 78 | dotnet_naming_rule.types_should_be_pascal_case.severity = suggestion 79 | dotnet_naming_rule.types_should_be_pascal_case.symbols = types 80 | dotnet_naming_rule.types_should_be_pascal_case.style = pascal_case 81 | 82 | dotnet_naming_rule.non_field_members_should_be_pascal_case.severity = suggestion 83 | dotnet_naming_rule.non_field_members_should_be_pascal_case.symbols = non_field_members 84 | dotnet_naming_rule.non_field_members_should_be_pascal_case.style = pascal_case 85 | 86 | # Symbol specifications 87 | 88 | dotnet_naming_symbols.interface.applicable_kinds = interface 89 | dotnet_naming_symbols.interface.applicable_accessibilities = public, internal, private, protected, protected_internal, private_protected 90 | dotnet_naming_symbols.interface.required_modifiers = 91 | 92 | dotnet_naming_symbols.types.applicable_kinds = class, struct, interface, enum 93 | dotnet_naming_symbols.types.applicable_accessibilities = public, internal, private, protected, protected_internal, private_protected 94 | dotnet_naming_symbols.types.required_modifiers = 95 | 96 | dotnet_naming_symbols.non_field_members.applicable_kinds = property, event, method 97 | dotnet_naming_symbols.non_field_members.applicable_accessibilities = public, internal, private, protected, protected_internal, private_protected 98 | dotnet_naming_symbols.non_field_members.required_modifiers = 99 | 100 | # Naming styles 101 | 102 | dotnet_naming_style.begins_with_i.required_prefix = I 103 | dotnet_naming_style.begins_with_i.required_suffix = 104 | dotnet_naming_style.begins_with_i.word_separator = 105 | dotnet_naming_style.begins_with_i.capitalization = pascal_case 106 | 107 | dotnet_naming_style.pascal_case.required_prefix = 108 | dotnet_naming_style.pascal_case.required_suffix = 109 | dotnet_naming_style.pascal_case.word_separator = 110 | dotnet_naming_style.pascal_case.capitalization = pascal_case 111 | 112 | dotnet_naming_style.pascal_case.required_prefix = 113 | dotnet_naming_style.pascal_case.required_suffix = 114 | dotnet_naming_style.pascal_case.word_separator = 115 | dotnet_naming_style.pascal_case.capitalization = pascal_case 116 | dotnet_style_coalesce_expression = true:suggestion 117 | dotnet_style_null_propagation = true:suggestion 118 | dotnet_style_prefer_is_null_check_over_reference_equality_method = true:suggestion 119 | dotnet_style_prefer_auto_properties = true:suggestion 120 | dotnet_style_object_initializer = true:suggestion 121 | dotnet_style_collection_initializer = true:suggestion 122 | dotnet_style_prefer_simplified_boolean_expressions = true:suggestion 123 | dotnet_style_prefer_conditional_expression_over_assignment = true:silent 124 | dotnet_style_operator_placement_when_wrapping = beginning_of_line 125 | tab_width = 4 126 | dotnet_style_prefer_conditional_expression_over_return = true:silent 127 | dotnet_style_explicit_tuple_names = true:suggestion 128 | dotnet_style_prefer_inferred_tuple_names = true:suggestion 129 | dotnet_style_prefer_inferred_anonymous_type_member_names = true:suggestion 130 | dotnet_style_prefer_simplified_interpolation = true:suggestion 131 | dotnet_style_prefer_compound_assignment = true:suggestion 132 | dotnet_style_namespace_match_folder = true:suggestion 133 | dotnet_style_prefer_collection_expression = when_types_loosely_match:suggestion 134 | dotnet_style_readonly_field = true:suggestion 135 | dotnet_style_predefined_type_for_locals_parameters_members = true:silent 136 | dotnet_style_predefined_type_for_member_access = true:silent 137 | -------------------------------------------------------------------------------- /src/GroupCache/CircuitBreakerClient.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | using System.IO; 12 | using System.Runtime.Serialization; 13 | using System.Threading; 14 | using System.Threading.Tasks; 15 | 16 | /// 17 | /// Usually when some server is slow/down/overloaded, we want to simply send request to a failover destination. 18 | /// Once server is marked bad, failover becomes instant, we don't need to do 2 round trips 19 | /// (one to known slow/broken box, one to failover destination) for a request. 20 | /// 21 | /// The CircuitBreaker will open after maxRetry request fail in a row. 22 | /// What happens after a client CircuitBreaker is open: 23 | /// 1- Every request sent to the Circuit breaker is immediately discarded with CircuitBreakerOpenException. 24 | /// 2- After backOff time have elapsed since last failed request circuit breaker will try sending one request. 25 | /// a- if that request succeed the Circuit Breaker is closed and let all request go through. 26 | /// 27 | public sealed class CircuitBreakerClient : IGroupCacheClient 28 | { 29 | private readonly object @lock = new object(); 30 | private readonly IGroupCacheClient client; 31 | private readonly TimeSpan backOff; 32 | private int sequentialFailure; 33 | private DateTimeOffset lastTry = DateTimeOffset.UtcNow; 34 | private readonly int maxRetry; 35 | 36 | /// 37 | /// Initializes a new instance of the class. 38 | /// 39 | /// 40 | public CircuitBreakerClient(IGroupCacheClient client) 41 | : this(client, TimeSpan.FromMinutes(10), 3) 42 | { 43 | } 44 | 45 | /// 46 | /// Initializes a new instance of the class. 47 | /// 48 | /// 49 | /// 50 | /// 51 | public CircuitBreakerClient(IGroupCacheClient client, TimeSpan backOff, int maxRetry) 52 | { 53 | this.client = client; 54 | this.backOff = backOff; 55 | this.maxRetry = maxRetry; 56 | } 57 | 58 | /// 59 | public PeerEndpoint Endpoint 60 | { 61 | get 62 | { 63 | return this.client.Endpoint; 64 | } 65 | } 66 | 67 | /// 68 | public bool IsLocal 69 | { 70 | get 71 | { 72 | return this.client.IsLocal; 73 | } 74 | } 75 | 76 | private bool IsOpen 77 | { 78 | get 79 | { 80 | return this.sequentialFailure >= this.maxRetry; 81 | } 82 | } 83 | 84 | private TimeSpan TimeSinceLastTry 85 | { 86 | get 87 | { 88 | return DateTimeOffset.Now - this.lastTry; 89 | } 90 | } 91 | 92 | /// 93 | public void Dispose() 94 | { 95 | this.client.Dispose(); 96 | } 97 | 98 | /// 99 | public async Task GetAsync(string group, string key, Stream sink, ICacheControl cacheControl, CancellationToken ct) 100 | { 101 | try 102 | { 103 | this.TripIfNeeded(); 104 | await this.client.GetAsync(group, key, sink, cacheControl, ct).ConfigureAwait(false); 105 | } 106 | catch (ServerBusyException) 107 | { 108 | // Dont count busy server as bad 109 | throw; 110 | } 111 | catch 112 | { 113 | this.CountFailure(); 114 | throw; 115 | } 116 | 117 | this.ResetCount(); 118 | } 119 | 120 | private void CountFailure() 121 | { 122 | lock (this.@lock) 123 | { 124 | if (!this.IsOpen) 125 | { 126 | this.sequentialFailure++; 127 | } 128 | } 129 | } 130 | 131 | private void ResetCount() 132 | { 133 | lock (this.@lock) 134 | { 135 | this.sequentialFailure = 0; 136 | } 137 | } 138 | 139 | private void TripIfNeeded() 140 | { 141 | lock (this.@lock) 142 | { 143 | if (this.IsOpen) 144 | { 145 | if (this.TimeSinceLastTry < this.backOff) 146 | { 147 | throw new CircuitBreakerOpenException(); 148 | } 149 | } 150 | 151 | this.lastTry = DateTimeOffset.UtcNow; 152 | } 153 | } 154 | } 155 | 156 | [Serializable] 157 | public class CircuitBreakerOpenException : Exception 158 | { 159 | /// 160 | /// Initializes a new instance of the class. 161 | /// 162 | public CircuitBreakerOpenException() 163 | { 164 | } 165 | 166 | /// 167 | /// Initializes a new instance of the class. 168 | /// 169 | /// 170 | public CircuitBreakerOpenException(string message) 171 | : base(message) 172 | { 173 | } 174 | 175 | /// 176 | /// Initializes a new instance of the class. 177 | /// 178 | /// 179 | /// 180 | public CircuitBreakerOpenException(string message, Exception innerException) 181 | : base(message, innerException) 182 | { 183 | } 184 | 185 | /// 186 | /// Initializes a new instance of the class. 187 | /// 188 | /// 189 | /// 190 | protected CircuitBreakerOpenException(SerializationInfo info, StreamingContext context) 191 | : base(info, context) 192 | { 193 | } 194 | } 195 | } 196 | -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | ## Ignore Visual Studio temporary files, build results, and 2 | ## files generated by popular Visual Studio add-ons. 3 | ## 4 | ## Get latest from https://github.com/github/gitignore/blob/master/VisualStudio.gitignore 5 | 6 | # User-specific files 7 | *.rsuser 8 | *.suo 9 | *.user 10 | *.userosscache 11 | *.sln.docstates 12 | 13 | # User-specific files (MonoDevelop/Xamarin Studio) 14 | *.userprefs 15 | 16 | # Mono auto generated files 17 | mono_crash.* 18 | 19 | # Build results 20 | [Dd]ebug/ 21 | [Dd]ebugPublic/ 22 | [Rr]elease/ 23 | [Rr]eleases/ 24 | x64/ 25 | x86/ 26 | [Aa][Rr][Mm]/ 27 | [Aa][Rr][Mm]64/ 28 | bld/ 29 | [Bb]in/ 30 | [Oo]bj/ 31 | [Ll]og/ 32 | [Ll]ogs/ 33 | 34 | # Visual Studio 2015/2017 cache/options directory 35 | .vs/ 36 | # Uncomment if you have tasks that create the project's static files in wwwroot 37 | #wwwroot/ 38 | 39 | # Visual Studio 2017 auto generated files 40 | Generated\ Files/ 41 | 42 | # MSTest test Results 43 | [Tt]est[Rr]esult*/ 44 | [Bb]uild[Ll]og.* 45 | 46 | # NUnit 47 | *.VisualState.xml 48 | TestResult.xml 49 | nunit-*.xml 50 | 51 | # Build Results of an ATL Project 52 | [Dd]ebugPS/ 53 | [Rr]eleasePS/ 54 | dlldata.c 55 | 56 | # Benchmark Results 57 | BenchmarkDotNet.Artifacts/ 58 | 59 | # .NET Core 60 | project.lock.json 61 | project.fragment.lock.json 62 | artifacts/ 63 | 64 | # StyleCop 65 | StyleCopReport.xml 66 | 67 | # Files built by Visual Studio 68 | *_i.c 69 | *_p.c 70 | *_h.h 71 | *.ilk 72 | *.meta 73 | *.obj 74 | *.iobj 75 | *.pch 76 | *.pdb 77 | *.ipdb 78 | *.pgc 79 | *.pgd 80 | *.rsp 81 | *.sbr 82 | *.tlb 83 | *.tli 84 | *.tlh 85 | *.tmp 86 | *.tmp_proj 87 | *_wpftmp.csproj 88 | *.log 89 | *.vspscc 90 | *.vssscc 91 | .builds 92 | *.pidb 93 | *.svclog 94 | *.scc 95 | 96 | # Chutzpah Test files 97 | _Chutzpah* 98 | 99 | # Visual C++ cache files 100 | ipch/ 101 | *.aps 102 | *.ncb 103 | *.opendb 104 | *.opensdf 105 | *.sdf 106 | *.cachefile 107 | *.VC.db 108 | *.VC.VC.opendb 109 | 110 | # Visual Studio profiler 111 | *.psess 112 | *.vsp 113 | *.vspx 114 | *.sap 115 | 116 | # Visual Studio Trace Files 117 | *.e2e 118 | 119 | # TFS 2012 Local Workspace 120 | $tf/ 121 | 122 | # Guidance Automation Toolkit 123 | *.gpState 124 | 125 | # ReSharper is a .NET coding add-in 126 | _ReSharper*/ 127 | *.[Rr]e[Ss]harper 128 | *.DotSettings.user 129 | 130 | # TeamCity is a build add-in 131 | _TeamCity* 132 | 133 | # DotCover is a Code Coverage Tool 134 | *.dotCover 135 | 136 | # AxoCover is a Code Coverage Tool 137 | .axoCover/* 138 | !.axoCover/settings.json 139 | 140 | # Visual Studio code coverage results 141 | *.coverage 142 | *.coveragexml 143 | 144 | # NCrunch 145 | _NCrunch_* 146 | .*crunch*.local.xml 147 | nCrunchTemp_* 148 | 149 | # MightyMoose 150 | *.mm.* 151 | AutoTest.Net/ 152 | 153 | # Web workbench (sass) 154 | .sass-cache/ 155 | 156 | # Installshield output folder 157 | [Ee]xpress/ 158 | 159 | # DocProject is a documentation generator add-in 160 | DocProject/buildhelp/ 161 | DocProject/Help/*.HxT 162 | DocProject/Help/*.HxC 163 | DocProject/Help/*.hhc 164 | DocProject/Help/*.hhk 165 | DocProject/Help/*.hhp 166 | DocProject/Help/Html2 167 | DocProject/Help/html 168 | 169 | # Click-Once directory 170 | publish/ 171 | 172 | # Publish Web Output 173 | *.[Pp]ublish.xml 174 | *.azurePubxml 175 | # Note: Comment the next line if you want to checkin your web deploy settings, 176 | # but database connection strings (with potential passwords) will be unencrypted 177 | *.pubxml 178 | *.publishproj 179 | 180 | # Microsoft Azure Web App publish settings. Comment the next line if you want to 181 | # checkin your Azure Web App publish settings, but sensitive information contained 182 | # in these scripts will be unencrypted 183 | PublishScripts/ 184 | 185 | # NuGet Packages 186 | *.nupkg 187 | # NuGet Symbol Packages 188 | *.snupkg 189 | # The packages folder can be ignored because of Package Restore 190 | **/[Pp]ackages/* 191 | # except build/, which is used as an MSBuild target. 192 | !**/[Pp]ackages/build/ 193 | # Uncomment if necessary however generally it will be regenerated when needed 194 | #!**/[Pp]ackages/repositories.config 195 | # NuGet v3's project.json files produces more ignorable files 196 | *.nuget.props 197 | *.nuget.targets 198 | 199 | # Microsoft Azure Build Output 200 | csx/ 201 | *.build.csdef 202 | 203 | # Microsoft Azure Emulator 204 | ecf/ 205 | rcf/ 206 | 207 | # Windows Store app package directories and files 208 | AppPackages/ 209 | BundleArtifacts/ 210 | Package.StoreAssociation.xml 211 | _pkginfo.txt 212 | *.appx 213 | *.appxbundle 214 | *.appxupload 215 | 216 | # Visual Studio cache files 217 | # files ending in .cache can be ignored 218 | *.[Cc]ache 219 | # but keep track of directories ending in .cache 220 | !?*.[Cc]ache/ 221 | 222 | # Others 223 | ClientBin/ 224 | ~$* 225 | *~ 226 | *.dbmdl 227 | *.dbproj.schemaview 228 | *.jfm 229 | *.pfx 230 | *.publishsettings 231 | orleans.codegen.cs 232 | 233 | # Including strong name files can present a security risk 234 | # (https://github.com/github/gitignore/pull/2483#issue-259490424) 235 | #*.snk 236 | 237 | # Since there are multiple workflows, uncomment next line to ignore bower_components 238 | # (https://github.com/github/gitignore/pull/1529#issuecomment-104372622) 239 | #bower_components/ 240 | 241 | # RIA/Silverlight projects 242 | Generated_Code/ 243 | 244 | # Backup & report files from converting an old project file 245 | # to a newer Visual Studio version. Backup files are not needed, 246 | # because we have git ;-) 247 | _UpgradeReport_Files/ 248 | Backup*/ 249 | UpgradeLog*.XML 250 | UpgradeLog*.htm 251 | ServiceFabricBackup/ 252 | *.rptproj.bak 253 | 254 | # SQL Server files 255 | *.mdf 256 | *.ldf 257 | *.ndf 258 | 259 | # Business Intelligence projects 260 | *.rdl.data 261 | *.bim.layout 262 | *.bim_*.settings 263 | *.rptproj.rsuser 264 | *- [Bb]ackup.rdl 265 | *- [Bb]ackup ([0-9]).rdl 266 | *- [Bb]ackup ([0-9][0-9]).rdl 267 | 268 | # Microsoft Fakes 269 | FakesAssemblies/ 270 | 271 | # GhostDoc plugin setting file 272 | *.GhostDoc.xml 273 | 274 | # Node.js Tools for Visual Studio 275 | .ntvs_analysis.dat 276 | node_modules/ 277 | 278 | # Visual Studio 6 build log 279 | *.plg 280 | 281 | # Visual Studio 6 workspace options file 282 | *.opt 283 | 284 | # Visual Studio 6 auto-generated workspace file (contains which files were open etc.) 285 | *.vbw 286 | 287 | # Visual Studio LightSwitch build output 288 | **/*.HTMLClient/GeneratedArtifacts 289 | **/*.DesktopClient/GeneratedArtifacts 290 | **/*.DesktopClient/ModelManifest.xml 291 | **/*.Server/GeneratedArtifacts 292 | **/*.Server/ModelManifest.xml 293 | _Pvt_Extensions 294 | 295 | # Paket dependency manager 296 | .paket/paket.exe 297 | paket-files/ 298 | 299 | # FAKE - F# Make 300 | .fake/ 301 | 302 | # CodeRush personal settings 303 | .cr/personal 304 | 305 | # Python Tools for Visual Studio (PTVS) 306 | __pycache__/ 307 | *.pyc 308 | 309 | # Cake - Uncomment if you are using it 310 | # tools/** 311 | # !tools/packages.config 312 | 313 | # Tabs Studio 314 | *.tss 315 | 316 | # Telerik's JustMock configuration file 317 | *.jmconfig 318 | 319 | # BizTalk build output 320 | *.btp.cs 321 | *.btm.cs 322 | *.odx.cs 323 | *.xsd.cs 324 | 325 | # OpenCover UI analysis results 326 | OpenCover/ 327 | 328 | # Azure Stream Analytics local run output 329 | ASALocalRun/ 330 | 331 | # MSBuild Binary and Structured Log 332 | *.binlog 333 | 334 | # NVidia Nsight GPU debugger configuration file 335 | *.nvuser 336 | 337 | # MFractors (Xamarin productivity tool) working folder 338 | .mfractor/ 339 | 340 | # Local History for Visual Studio 341 | .localhistory/ 342 | 343 | # BeatPulse healthcheck temp database 344 | healthchecksdb 345 | 346 | # Backup folder for Package Reference Convert tool in Visual Studio 2017 347 | MigrationBackup/ 348 | 349 | # Ionide (cross platform F# VS Code tools) working folder 350 | .ionide/ 351 | -------------------------------------------------------------------------------- /src/GroupCache/Argument.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | using System.Diagnostics; 12 | 13 | public static class Argument 14 | { 15 | /// 16 | /// Helper function to allow simple if check ArgumentNull exception. 17 | /// 18 | /// parameter value to check for null. 19 | /// name of the parameter. 20 | /// 21 | /// DoSomething.(this IEnumerable list, Action action) 22 | /// { 23 | /// ArgumetValidator.NotNull(list,"list"); 24 | /// ArgumetValidator.NotNull(action,"action"); 25 | /// 26 | /// 27 | public static void NotNull(object param, string parameterName) 28 | { 29 | if (param == null) 30 | { 31 | throw new ArgumentNullException(parameterName); 32 | } 33 | } 34 | 35 | /// 36 | /// Helper function to allow simple if check validations and exception throwing. 37 | /// 38 | /// Condition. if false, Throws ArgumentException. 39 | /// Message for the ArgumentException. 40 | /// optional parameter name for the ArgumentException. 41 | /// 42 | /// DoSomething.(this IEnumerable list, Action action) 43 | /// { 44 | /// ArgumetValidator.IsTrue(list.Contains(s=>s==1), "Enumerable does not contain 1","list."); 45 | /// ArgumetValidator.IsTrue(list.Contains(s=>s==2), "Enumerable does not contain 1"); 46 | /// 47 | public static void IsTrue(bool condition, string message, string parameterName = null) 48 | { 49 | if (!condition) 50 | { 51 | if (!string.IsNullOrEmpty(parameterName)) 52 | { 53 | throw new ArgumentException(message, parameterName); 54 | } 55 | else 56 | { 57 | throw new ArgumentException(message); 58 | } 59 | } 60 | } 61 | 62 | /// 63 | /// Helper function to allow simple if check validations and exception throwing. 64 | /// 65 | /// Condition. if true, Throws ArgumentException. 66 | /// Message for the ArgumentException. 67 | /// optional parameter name for the ArgumentException. 68 | /// 69 | /// DoSomething.(this IEnumerable list, Action action) 70 | /// { 71 | /// ArgumetValidator.IsFalse(list.Contains(s=>s==1), "Enumerable contains 1","list."); 72 | /// 73 | public static void IsFalse(bool condition, string message, string parameterName = null) 74 | { 75 | if (condition) 76 | { 77 | if (!string.IsNullOrEmpty(parameterName)) 78 | { 79 | throw new ArgumentException(message, parameterName); 80 | } 81 | else 82 | { 83 | throw new ArgumentException(message); 84 | } 85 | } 86 | } 87 | 88 | /// 89 | /// Compares two types and returns if value is out of range. 90 | /// 91 | /// numeric type (works for some other types but definitely works for numeric types. 92 | /// Name of parameter. 93 | /// Value of parameter. 94 | /// Minimum value, inclusive. 95 | /// Maximum value, exclusive. 96 | /// 97 | /// someVal.InRange(minValue, maxValue, "SomeParam");. 98 | /// 99 | public static void InRange(IComparable value, T maxExclusive, string paramName) 100 | { 101 | InRange(value, minInclusive: default(T), maxExclusive: maxExclusive, paramName: paramName); 102 | } 103 | 104 | /// 105 | /// Compares two types and returns if value is out of range. 106 | /// 107 | /// numeric type (works for some other types but definitely works for numeric types. 108 | /// Name of parameter. 109 | /// Value of parameter. 110 | /// Minimum value, inclusive. 111 | /// Maximum value, exclusive. 112 | /// 113 | /// someVal.InRange(minValue, maxValue, "SomeParam");. 114 | /// 115 | public static void InRange(IComparable value, T minInclusive, T maxExclusive, string paramName) 116 | { 117 | NotNull(value, paramName); 118 | 119 | if (value.CompareTo(minInclusive) < 0 || value.CompareTo(maxExclusive) >= 0) 120 | { 121 | throw new ArgumentOutOfRangeException( 122 | paramName, 123 | FormatRangeErrorMsg(value, minInclusive, maxExclusive)); 124 | } 125 | } 126 | 127 | public static string FormatRangeErrorMsg(IComparable value, T minInclusive, T maxExclusive) 128 | { 129 | return string.Format("Value {2} should be in range [{0}..{1})", minInclusive, maxExclusive, value); 130 | } 131 | 132 | public static void NotNullOrEmpty(string name, string argName) 133 | { 134 | if (string.IsNullOrEmpty(name)) 135 | { 136 | throw new ArgumentNullException(argName + " cannot be null or empty"); 137 | } 138 | } 139 | 140 | public static void NotNullOrWhiteSpace(string name, string argName) 141 | { 142 | if (string.IsNullOrWhiteSpace(name)) 143 | { 144 | throw new ArgumentNullException(argName, argName + " cannot be null or whitespace"); 145 | } 146 | } 147 | 148 | public static void Requires(bool condition) 149 | where TException : Exception, new() 150 | { 151 | if (!condition) 152 | { 153 | throw new TException(); 154 | } 155 | } 156 | 157 | public static void Requires(bool condition, string what) 158 | where TException : Exception, new() 159 | { 160 | if (!condition) 161 | { 162 | var type = typeof(TException); 163 | var ctor = type.GetConstructor(new[] { typeof(string) }); 164 | if (ctor != null) 165 | { 166 | var ex = ctor.Invoke(new object[] { what }); 167 | throw ex as TException; 168 | } 169 | else 170 | { 171 | throw new TException(); 172 | } 173 | } 174 | } 175 | 176 | [Conditional("DEBUG")] 177 | public static void RequiresDebugOnly(bool condition) 178 | where TException : Exception, new() 179 | { 180 | Requires(condition); 181 | } 182 | 183 | [Conditional("DEBUG")] 184 | public static void RequiresDebugOnly(bool condition, string what) 185 | where TException : Exception, new() 186 | { 187 | Requires(condition, what); 188 | } 189 | } 190 | } -------------------------------------------------------------------------------- /test/GroupCacheStubTest/TestStub.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCacheStubTest 9 | { 10 | using System; 11 | using System.IO; 12 | using System.Threading; 13 | using System.Threading.Tasks; 14 | using GroupCache; 15 | using GroupCacheStub; 16 | using Xunit; 17 | 18 | public sealed class GroupCacheHandler : IGroupCacheClient 19 | { 20 | /// 21 | public void Dispose() 22 | { 23 | } 24 | 25 | /// 26 | public bool IsLocal 27 | { 28 | get { return true; } 29 | } 30 | 31 | /// 32 | public PeerEndpoint Endpoint => throw new NotImplementedException(); 33 | 34 | /// 35 | public async Task GetAsync(string group, string key, Stream sink, ICacheControl cacheControl, CancellationToken ct) 36 | { 37 | using (var resultStream = "HelloWorld".StringToStream()) 38 | { 39 | await resultStream.CopyToAsync(sink); 40 | } 41 | 42 | return; 43 | } 44 | } 45 | 46 | public sealed class GroupCacheHandlerNoStore : IGroupCacheClient 47 | { 48 | /// 49 | public void Dispose() 50 | { 51 | } 52 | 53 | /// 54 | public bool IsLocal 55 | { 56 | get { return true; } 57 | } 58 | 59 | /// 60 | public PeerEndpoint Endpoint => throw new NotImplementedException(); 61 | 62 | /// 63 | public async Task GetAsync(string group, string key, Stream sink, ICacheControl cacheControl, CancellationToken ct) 64 | { 65 | cacheControl.NoStore = true; 66 | using (var resultStream = "HelloWorld".StringToStream()) 67 | { 68 | await resultStream.CopyToAsync(sink); 69 | } 70 | } 71 | } 72 | 73 | public sealed class BadGroupCacheHandler : IGroupCacheClient 74 | { 75 | /// 76 | public void Dispose() 77 | { 78 | } 79 | 80 | /// 81 | public bool IsLocal 82 | { 83 | get { return true; } 84 | } 85 | 86 | /// 87 | public PeerEndpoint Endpoint => throw new NotImplementedException(); 88 | 89 | /// 90 | public Task GetAsync(string group, string key, Stream sink, ICacheControl cacheControl, CancellationToken ct) 91 | { 92 | return Task.FromException(new InvalidOperationException("test")); 93 | } 94 | } 95 | 96 | public class TestStub 97 | { 98 | [Fact] 99 | public async Task TestHelloWorldAsync() 100 | { 101 | var host = "localhost"; 102 | var port = 60051; 103 | var handler = new GroupCacheHandler(); 104 | using (var server = new OwinServer(handler, port, host)) 105 | { 106 | server.Start(); 107 | var endpoint = new PeerEndpoint() { HostName = host, Port = port }; 108 | using (var client = new OwinClient(endpoint)) 109 | { 110 | using (var stream = new MemoryStream()) 111 | { 112 | var cacheControl = new CacheControl(); 113 | await client.GetAsync("groupA", "key1", stream, cacheControl, CancellationToken.None); 114 | var str = stream.StreamToString(); 115 | Xunit.Assert.Equal("HelloWorld", str); 116 | Xunit.Assert.False(cacheControl.NoStore); 117 | } 118 | } 119 | } 120 | } 121 | 122 | [Fact] 123 | public async Task TestHelloWorldNoStoreAsync() 124 | { 125 | var host = "localhost"; 126 | var port = 60051; 127 | var handler = new GroupCacheHandlerNoStore(); 128 | using (var server = new OwinServer(handler, port, host)) 129 | { 130 | server.Start(); 131 | var endpoint = new PeerEndpoint() { HostName = host, Port = port }; 132 | using (var client = new OwinClient(endpoint)) 133 | { 134 | using (var stream = new MemoryStream()) 135 | { 136 | var cacheControl = new CacheControl(); 137 | await client.GetAsync("groupA", "key1", stream, cacheControl, CancellationToken.None); 138 | var str = stream.StreamToString(); 139 | Xunit.Assert.Equal("HelloWorld", str); 140 | Xunit.Assert.True(cacheControl.NoStore); 141 | } 142 | } 143 | } 144 | } 145 | 146 | [Fact] 147 | public async Task TestCancellationAsync() 148 | { 149 | var host = "localhost"; 150 | var port = 60051; 151 | var handler = new GroupCacheHandler(); 152 | 153 | using (var tokenSource = new CancellationTokenSource()) 154 | { 155 | tokenSource.Cancel(); 156 | var ct = tokenSource.Token; 157 | using (var server = new OwinServer(handler, port, host)) 158 | { 159 | server.Start(); 160 | var endpoint = new PeerEndpoint() { HostName = host, Port = port }; 161 | using (var client = new OwinClient(endpoint)) 162 | { 163 | using (var stream = new MemoryStream()) 164 | { 165 | await Xunit.Assert.ThrowsAsync(async () => 166 | { 167 | await client.GetAsync("groupA", "key1", stream, new CacheControl(), ct); 168 | var str = stream.StreamToString(); 169 | Xunit.Assert.Fail("Should have thrown"); 170 | }); 171 | } 172 | } 173 | } 174 | } 175 | } 176 | 177 | [Fact] 178 | public async Task TestServerSideExceptionAsync() 179 | { 180 | var host = "localhost"; 181 | var port = 60051; 182 | var handler = new BadGroupCacheHandler(); 183 | 184 | using (var server = new OwinServer(handler, port, host)) 185 | { 186 | server.Start(); 187 | var endpoint = new PeerEndpoint() { HostName = host, Port = port }; 188 | using (var client = new OwinClient(endpoint)) 189 | { 190 | using (var stream = new MemoryStream()) 191 | { 192 | await Xunit.Assert.ThrowsAsync(async () => 193 | { 194 | await client.GetAsync("groupA", "key1", stream, new CacheControl(), CancellationToken.None); 195 | var str = stream.StreamToString(); 196 | Xunit.Assert.Fail("Should have thrown"); 197 | }); 198 | } 199 | } 200 | } 201 | } 202 | 203 | [Fact] 204 | public async Task TestUnavailableAsync() 205 | { 206 | var host = "localhost"; 207 | var badPort = 666; 208 | var handler = new GroupCacheHandler(); 209 | var endpoint = new PeerEndpoint() { HostName = host, Port = badPort }; 210 | using (var client = new OwinClient(endpoint)) 211 | { 212 | using (var stream = new MemoryStream()) 213 | { 214 | await Xunit.Assert.ThrowsAsync(async () => 215 | { 216 | await client.GetAsync("groupA", "key1", stream, new CacheControl(), CancellationToken.None); 217 | var str = stream.StreamToString(); 218 | Xunit.Assert.Fail("Should have thrown"); 219 | }); 220 | } 221 | } 222 | } 223 | } 224 | } 225 | -------------------------------------------------------------------------------- /test/GroupCacheStubTest/TestGroupCache.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCacheStubTest 9 | { 10 | using System; 11 | using System.Collections.Generic; 12 | using System.IO; 13 | using System.Text; 14 | using System.Threading; 15 | using System.Threading.Tasks; 16 | using GroupCache; 17 | using Xunit; 18 | 19 | public static class StreamHelper 20 | { 21 | public static string StreamToString(this Stream stream) 22 | { 23 | stream.Position = 0; 24 | using (StreamReader reader = new StreamReader(stream, Encoding.UTF8)) 25 | { 26 | return reader.ReadToEnd(); 27 | } 28 | } 29 | 30 | public static Stream StringToStream(this string src) 31 | { 32 | byte[] byteArray = Encoding.UTF8.GetBytes(src); 33 | return new MemoryStream(byteArray); 34 | } 35 | } 36 | 37 | public class HelloGetter : IGetter 38 | { 39 | public string PeerName; 40 | public int CallCount = 0; 41 | 42 | public async Task GetAsync(string key, Stream sink, ICacheControl cacheControl, CancellationToken ct) 43 | { 44 | Interlocked.Increment(ref this.CallCount); 45 | using (var stream = key.StringToStream()) 46 | { 47 | await stream.CopyToAsync(sink); 48 | } 49 | } 50 | } 51 | 52 | public class FibGetter : IGetter 53 | { 54 | public IGetter Getter; 55 | public int CallCount = 0; 56 | 57 | public async Task GetAsync(string key, Stream sink, ICacheControl cacheControl, CancellationToken ct) 58 | { 59 | Interlocked.Increment(ref this.CallCount); 60 | try 61 | { 62 | long number = long.Parse(key); 63 | long result; 64 | if (number == 0) 65 | { 66 | result = 0; 67 | } 68 | else if (number == 1) 69 | { 70 | result = 1; 71 | } 72 | else 73 | { 74 | // Make to call to n-1 and n-2 in parallel 75 | using (var firstStream = new MemoryStream()) 76 | using (var secondStream = new MemoryStream()) 77 | { 78 | await this.Getter.GetAsync((number - 1).ToString(), firstStream, new CacheControl(), CancellationToken.None).ConfigureAwait(false); 79 | await this.Getter.GetAsync((number - 2).ToString(), secondStream, new CacheControl(), CancellationToken.None).ConfigureAwait(false); 80 | var firstStr = firstStream.StreamToString(); 81 | var secondStr = secondStream.StreamToString(); 82 | 83 | // return the sum 84 | var firstLong = long.Parse(firstStr); 85 | var secondLong = long.Parse(secondStr); 86 | result = firstLong + secondLong; 87 | } 88 | } 89 | 90 | var resultStream = result.ToString().StringToStream(); 91 | resultStream.Position = 0; 92 | await resultStream.CopyToAsync(sink); 93 | } 94 | catch (Exception ex) 95 | { 96 | Console.WriteLine(ex.ToString()); 97 | throw; 98 | } 99 | } 100 | } 101 | 102 | public class TestGroupCache : IDisposable 103 | { 104 | private readonly GroupCacheStub.OwinPool peer1Pool; 105 | private readonly GroupCacheStub.OwinPool peer2Pool; 106 | 107 | public TestGroupCache() 108 | { 109 | var peer1 = new PeerEndpoint { HostName = "localhost", Port = 60053 }; 110 | var peer2 = new PeerEndpoint { HostName = "localhost", Port = 60054 }; 111 | var peerList = new List { peer1, peer2 }; 112 | 113 | // server listening on port 50053 114 | this.peer1Pool = new GroupCacheStub.OwinPool(peer1); 115 | this.peer1Pool.GetPicker("TestGroupForwarding").Add(peerList); 116 | this.peer1Pool.GetPicker("Fibonacci").Add(peerList); 117 | 118 | // server listening on port 50054 119 | this.peer2Pool = new GroupCacheStub.OwinPool(peer2); 120 | this.peer2Pool.GetPicker("TestGroupForwarding").Add(peerList); 121 | this.peer2Pool.GetPicker("Fibonacci").Add(peerList); 122 | } 123 | 124 | public void Dispose() 125 | { 126 | this.peer1Pool.Dispose(); 127 | this.peer2Pool.Dispose(); 128 | } 129 | 130 | [Fact] 131 | public void TestGroupForwarding() 132 | { 133 | var getter1 = new HelloGetter { PeerName = "peer1" }; 134 | var getter2 = new HelloGetter { PeerName = "peer2" }; 135 | var fooResponse = "foo"; 136 | var barResponse = "bar"; 137 | var peer1Group = GroupCache.NewGroup("TestGroupForwarding", getter1, this.peer1Pool.GetPicker("TestGroupForwarding")); 138 | var peer2Group = GroupCache.NewGroup("TestGroupForwarding", getter2, this.peer2Pool.GetPicker("TestGroupForwarding")); 139 | var group1Stat = new UnitTestGroupStat(); 140 | var group2Stat = new UnitTestGroupStat(); 141 | peer1Group.Stats = group1Stat; 142 | peer2Group.Stats = group2Stat; 143 | using (var result1a = new MemoryStream()) 144 | using (var result1b = new MemoryStream()) 145 | using (var result2a = new MemoryStream()) 146 | using (var result2b = new MemoryStream()) 147 | { 148 | peer1Group.GetAsync("foo", result1a, new CacheControl(), CancellationToken.None).Wait(); 149 | peer1Group.GetAsync("bar", result1b, new CacheControl(), CancellationToken.None).Wait(); 150 | peer2Group.GetAsync("foo", result2a, new CacheControl(), CancellationToken.None).Wait(); 151 | peer2Group.GetAsync("bar", result2b, new CacheControl(), CancellationToken.None).Wait(); 152 | var result1aStr = result1a.StreamToString(); 153 | Xunit.Assert.Equal(fooResponse, result1aStr); 154 | var result1bStr = result1b.StreamToString(); 155 | Xunit.Assert.Equal(barResponse, result1bStr); 156 | var result2aStr = result2a.StreamToString(); 157 | Xunit.Assert.Equal(fooResponse, result2aStr); 158 | var result2bStr = result2b.StreamToString(); 159 | Xunit.Assert.Equal(barResponse, result2bStr); 160 | } 161 | 162 | using (var result3a = new MemoryStream()) 163 | using (var result3b = new MemoryStream()) 164 | using (var result4a = new MemoryStream()) 165 | using (var result4b = new MemoryStream()) 166 | { 167 | peer1Group.GetAsync("foo", result3a, new CacheControl(), CancellationToken.None).Wait(); 168 | result3a.Position = 0; 169 | peer1Group.GetAsync("bar", result3b, new CacheControl(), CancellationToken.None).Wait(); 170 | result3b.Position = 0; 171 | peer2Group.GetAsync("foo", result4a, new CacheControl(), CancellationToken.None).Wait(); 172 | result4a.Position = 0; 173 | peer2Group.GetAsync("bar", result4b, new CacheControl(), CancellationToken.None).Wait(); 174 | result4b.Position = 0; 175 | } 176 | 177 | Xunit.Assert.Equal(2, getter1.CallCount + getter2.CallCount); 178 | Xunit.Assert.Equal(2, group1Stat.LocalLoads + group2Stat.LocalLoads); 179 | } 180 | 181 | [Fact] 182 | public async Task TestFibonacciAsync() 183 | { 184 | var fibGetter1 = new FibGetter { CallCount = 0 }; 185 | var fibGetter2 = new FibGetter { CallCount = 0 }; 186 | var groupName = "Fibonacci"; 187 | var peer1Group = GroupCache.NewGroup(groupName, fibGetter1, this.peer1Pool.GetPicker(groupName)); 188 | var peer2Group = GroupCache.NewGroup(groupName, fibGetter2, this.peer2Pool.GetPicker(groupName)); 189 | var group1Stat = new UnitTestGroupStat(); 190 | var group2Stat = new UnitTestGroupStat(); 191 | peer1Group.Stats = group1Stat; 192 | peer2Group.Stats = group2Stat; 193 | fibGetter1.Getter = peer1Group; 194 | fibGetter2.Getter = peer2Group; 195 | using (var result1a = new MemoryStream()) 196 | { 197 | await peer1Group.GetAsync("90", result1a, new CacheControl(), CancellationToken.None); 198 | var result1aStr = result1a.StreamToString(); 199 | Xunit.Assert.Equal("2880067194370816120", result1aStr); 200 | } 201 | 202 | Xunit.Assert.Equal(group1Stat.PeerLoads + group2Stat.PeerLoads, group1Stat.ServerRequests + group2Stat.ServerRequests); 203 | Xunit.Assert.Equal(91, group1Stat.LocalLoads + group2Stat.LocalLoads); 204 | Xunit.Assert.Equal(91, fibGetter1.CallCount + fibGetter2.CallCount); 205 | using (var result1b = new MemoryStream()) 206 | { 207 | await peer2Group.GetAsync("90", result1b, new CacheControl(), CancellationToken.None); 208 | var result1bStr = result1b.StreamToString(); 209 | Xunit.Assert.Equal("2880067194370816120", result1bStr); 210 | } 211 | 212 | Xunit.Assert.Equal(91, fibGetter1.CallCount + fibGetter2.CallCount); 213 | } 214 | } 215 | } 216 | -------------------------------------------------------------------------------- /src/GroupCache/GroupCache.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | using System.Collections.Concurrent; 12 | using System.Diagnostics; 13 | using System.IO; 14 | using System.Threading; 15 | using System.Threading.Tasks; 16 | 17 | /// 18 | /// Groupcache provides a data loading mechanism with caching and de-duplication 19 | /// that works across a set of peer processes. 20 | /// 21 | /// Each data Get first consults its local cache, otherwise delegates to the requested key's canonical owner, 22 | /// which then checks its cache or finally gets the data. 23 | /// 24 | /// In the common case, many concurrent cache misses across 25 | /// a set of peers for the same key result in just one cache fill. 26 | /// 27 | /// In a nutshell, a groupcache lookup of Get("foo") looks like: 28 | /// (On machine #5 of a set of N machines running the same code) 29 | /// 30 | /// 1- Is the value of "foo" in local memory because peer #5 (the current peer) is the owner of it? If so, use it. 31 | /// 32 | /// 2- Amongst the peers in my set of N, am I the owner of the key "foo"? (e.g.does it hash to 5?) If so, load it. 33 | /// If other callers come in, via the same process or via RPC requests from peers, they block waiting for the load to finish and get the same answer. 34 | /// If not, RPC to the peer that's the owner and get to the answer. 35 | /// If the RPC fails, just try again next canonical owner for that key (still with local dup suppression). 36 | /// 37 | public static class GroupCache 38 | { 39 | private static readonly ConcurrentDictionary GROUPS = new ConcurrentDictionary(); 40 | 41 | /// 42 | /// returns the named group previously created with NewGroup, 43 | /// Used by server callback to forward received request to the correct Group instance. 44 | /// 45 | /// 46 | public static bool GetGroup(GroupKey key, out Group group) 47 | { 48 | return GROUPS.TryGetValue(key, out group); 49 | } 50 | 51 | public static Group NewGroup(string groupName, Func getterFunc, IPeerPicker peers) 52 | { 53 | Argument.NotNull(getterFunc, "getterFunc"); 54 | var getter = new GetterFunc(getterFunc); 55 | return NewGroup(groupName, getter, peers); 56 | } 57 | 58 | public static Group NewGroup(string name, IGetter getter, ICache cache, IPeerPicker peers) 59 | { 60 | Argument.NotNull(name, "name"); 61 | Argument.NotNull(getter, "getter"); 62 | Argument.NotNull(cache, "cache"); 63 | Argument.NotNull(peers, "peers"); 64 | var groupKey = new GroupKey { GroupName = name, Endpoint = peers.Self }; 65 | var group = new Group(name, getter, peers, cache); 66 | return GROUPS.GetOrAdd(groupKey, group); 67 | } 68 | 69 | public static Group NewGroup(string name, IGetter getter, IPeerPicker peers) 70 | { 71 | Argument.NotNull(name, "name"); 72 | Argument.NotNull(getter, "getter"); 73 | Argument.NotNull(peers, "peers"); 74 | var groupKey = new GroupKey { GroupName = name, Endpoint = peers.Self }; 75 | var group = new Group(name, getter, peers); 76 | return GROUPS.GetOrAdd(groupKey, group); 77 | } 78 | } 79 | 80 | /// 81 | /// A Group is a cache namespace and associated data loaded spread over a group of 1 or more machines. 82 | /// 83 | public sealed class Group : IGetter 84 | { 85 | private readonly string groupName; 86 | private readonly IGetter getter; 87 | private readonly IPeerPicker peers; 88 | private readonly ICache localCache; 89 | private IGroupStat stats; 90 | private ILogger logger; 91 | 92 | public IGroupStat Stats 93 | { 94 | get 95 | { 96 | return this.stats; 97 | } 98 | 99 | set 100 | { 101 | Argument.NotNull(value, "Stats"); 102 | this.stats = value; 103 | } 104 | } 105 | 106 | public ILogger Logger 107 | { 108 | get 109 | { 110 | return this.logger; 111 | } 112 | 113 | set 114 | { 115 | Argument.NotNull(value, "Logger"); 116 | this.logger = value; 117 | } 118 | } 119 | 120 | public int MaxRetry { get; set; } = 5; 121 | 122 | public ICacheEntryValidator CacheEntryValidator { get; set; } 123 | 124 | internal Group(string groupName, IGetter getter, IPeerPicker peers) 125 | : this(groupName, getter, peers, new MemoryCache()) 126 | { 127 | } 128 | 129 | internal Group(string groupName, IGetter getter, IPeerPicker peers, ICache localCache) 130 | { 131 | this.groupName = groupName; 132 | this.getter = getter; 133 | this.peers = peers; 134 | this.localCache = localCache; 135 | this.Stats = new NullGroupStat(); 136 | this.Logger = new NullLogger(); 137 | this.localCache.ItemOverCapacity += this.ItemWasOverCapacity; 138 | this.CacheEntryValidator = new NullCacheEntryValidator(); 139 | } 140 | 141 | private void ItemWasOverCapacity(string obj) 142 | { 143 | this.Stats.TraceItemOverCapacity(this.groupName); 144 | } 145 | 146 | /// 147 | /// Read the data from Peer or local machine and dedup in flight call. 148 | /// 149 | /// A representing the asynchronous operation. 150 | public async Task GetAsync(string key, Stream sink, ICacheControl cacheControl, CancellationToken ct) 151 | { 152 | if (cacheControl == null) 153 | { 154 | cacheControl = new CacheControl(); 155 | } 156 | 157 | this.Stats.TraceGets(this.groupName); 158 | var watch = Stopwatch.StartNew(); 159 | await this.LoadFromGetterOrPeerAsync(key, sink, cacheControl, ct).ConfigureAwait(false); 160 | this.Stats.TraceRoundtripLatency(this.groupName, watch.Elapsed); 161 | } 162 | 163 | /// 164 | /// Read the data from localMachine or from IGetter and dedup in flight call. 165 | /// 166 | /// A representing the asynchronous operation. 167 | public async Task GetAsyncLocallyAsync(string key, Stream sink, ICacheControl cacheControl, CancellationToken ct) 168 | { 169 | this.Stats.TraceGets(this.groupName); 170 | 171 | // Dipose validatingSink but leave sink open, to release validatingSink ressources 172 | using (var validatingSink = this.CacheEntryValidator.ValidateEntryPassThrough(key, sink)) 173 | { 174 | try 175 | { 176 | await this.LoadLocallyAsync(key, validatingSink, cacheControl, ct).ConfigureAwait(false); 177 | await validatingSink.ValidateAsync(ct).ConfigureAwait(false); 178 | } 179 | catch (CacheEntryValidationFailedException) 180 | { 181 | await this.RemoveAsync(key, ct).ConfigureAwait(false); 182 | throw; 183 | } 184 | } 185 | } 186 | 187 | public Task RemoveAsync(string key, CancellationToken ct) 188 | { 189 | return this.localCache.RemoveAsync(key, ct); 190 | } 191 | 192 | private async Task LoadFromGetterOrPeerAsync(string key, Stream sink, ICacheControl cacheControl, CancellationToken ct) 193 | { 194 | this.Stats.TraceLoadsDeduped(this.groupName); 195 | var replicasForKey = this.peers.PickPeers(key, this.peers.Count); 196 | var retryCount = Math.Min(this.MaxRetry, replicasForKey.Count); 197 | var retryableException = new Type[] { typeof(InternalServerErrorException), typeof(ServerBusyException), typeof(GroupNotFoundException), typeof(ConnectFailureException) }; 198 | var retry = new Retry(new SimpleRetryPolicy(retryCount, TimeSpan.Zero, retryableException)); 199 | try 200 | { 201 | await retry.ExecuteAsync(async (RetryContext ctx) => 202 | { 203 | if (ctx.RetryCount > 0) 204 | { 205 | this.Stats.TraceRetry(this.groupName); 206 | } 207 | 208 | var peerClient = replicasForKey[ctx.RetryCount]; 209 | if (peerClient.IsLocal) // we need to read from peer 210 | { 211 | this.Logger.Debug(string.Format("Call to LoadLocally for Cache {0} key: {1} retryCount: {2}", this.groupName, key, ctx.RetryCount)); 212 | await this.LoadLocallyAsync(key, sink, cacheControl, ct).ConfigureAwait(false); 213 | } 214 | else 215 | { 216 | this.Logger.Debug(string.Format("Call to LoadFromPeer for Cache {0} key: {1} retryCount: {2}", this.groupName, key, ctx.RetryCount)); 217 | await this.LoadFromPeerAsync(key, sink, cacheControl, peerClient, ct).ConfigureAwait(false); 218 | } 219 | }) 220 | .ConfigureAwait(false); 221 | } 222 | catch 223 | { 224 | this.Logger.Info($"{this.groupName}:{key} failed to download from peer. trying to download locally from source directly."); 225 | await this.LoadLocallyAsync(key, sink, cacheControl, ct).ConfigureAwait(false); 226 | } 227 | } 228 | 229 | private async Task LoadLocallyAsync(string key, Stream sink, ICacheControl cacheControl, CancellationToken ct) 230 | { 231 | async Task Func(string cachekey, Stream factorySink, ICacheControl factoryCacheControl) 232 | { 233 | try 234 | { 235 | this.Stats.TraceLocalLoads(this.groupName); 236 | await this.getter.GetAsync(cachekey, factorySink, factoryCacheControl, ct).ConfigureAwait(false); 237 | } 238 | catch (Exception ex) 239 | { 240 | this.Logger.Error(ex, string.Format("Call to LoadLocally for Cache {0} key: {1} failed ", this.groupName, key)); 241 | throw; 242 | } 243 | } 244 | 245 | this.Stats.TraceCacheHits(this.groupName); 246 | 247 | var cacheEntry = await this.localCache.GetOrAddAsync(key, Func, cacheControl, ct).ConfigureAwait(false); 248 | try 249 | { 250 | Stream cacheEntryStream = cacheEntry.Value(); 251 | await cacheEntryStream.CopyToAsync(sink).ConfigureAwait(false); 252 | } 253 | finally 254 | { 255 | await cacheEntry.DisposeAsync().ConfigureAwait(false); 256 | } 257 | } 258 | 259 | private async Task LoadFromPeerAsync(string key, Stream sink, ICacheControl cacheControl, IGroupCacheClient peerClient, CancellationToken ct) 260 | { 261 | try 262 | { 263 | this.Stats.TracePeerLoads(this.groupName); 264 | using (var validatingSink = this.CacheEntryValidator.ValidateEntryPassThrough(key, sink)) 265 | { 266 | await peerClient.GetAsync(this.groupName, key, validatingSink, cacheControl, ct).ConfigureAwait(false); 267 | await validatingSink.ValidateAsync(ct).ConfigureAwait(false); 268 | } 269 | } 270 | catch (CircuitBreakerOpenException) 271 | { 272 | throw; // Dont log CircuitBreakerOpenException 273 | } 274 | catch (InternalServerErrorException internalErrorEx) 275 | { 276 | this.Logger.Error(string.Format("Call to LoadFromPeer to {0} for Cache {1} key: {2} failed on InternalServerErrorException {3}", peerClient.Endpoint.ToString(), this.groupName, key, internalErrorEx.Message)); 277 | throw; 278 | } 279 | catch (Exception ex) 280 | { 281 | this.Logger.Error(ex, string.Format("Call to LoadFromPeer to {0} for Cache {1} key: {2} failed ", peerClient.Endpoint.ToString(), this.groupName, key)); 282 | throw; 283 | } 284 | } 285 | } 286 | } 287 | -------------------------------------------------------------------------------- /src/GroupCache/LRUCache.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | using System.Collections; 12 | using System.Collections.Generic; 13 | using System.Linq; 14 | using System.Threading; 15 | 16 | /// 17 | /// Implements a Generic fixed-size thread safe LRU (Least Recently Used) cache. 18 | /// The object maintains a doubly-linked list of elements. 19 | /// When an element is accessed, it is promoted to the head of the list. 20 | /// When space is needed, the element at the tail of the list (the least recently used element) is evicted. 21 | /// 22 | /// The type of the keys in the cache. 23 | /// The type of the values in the cache. 24 | public class LRUCache : IEnumerable>, IDisposable 25 | { 26 | private readonly ReaderWriterLockSlim @lock; 27 | private readonly LinkedList> lruList; 28 | private readonly Dictionary>> map; 29 | private readonly int maxEntries; 30 | private ulong capacity; 31 | private TimeSpan ttl = TimeSpan.MaxValue; 32 | private ulong usage = 0; 33 | 34 | public ulong Capacity 35 | { 36 | get 37 | { 38 | using (this.@lock.GetReaderLock()) 39 | { 40 | return this.capacity; 41 | } 42 | } 43 | 44 | set 45 | { 46 | using (this.@lock.GetWriterLock()) 47 | { 48 | this.capacity = value; 49 | } 50 | } 51 | } 52 | 53 | public event Action> ItemEvicted; 54 | 55 | public event Action> ItemOverCapacity; 56 | 57 | /// 58 | /// Gets returns the number of items in the cache. 59 | /// 60 | public int Count 61 | { 62 | get 63 | { 64 | using (this.@lock.GetReaderLock()) 65 | { 66 | return this.lruList.Count; 67 | } 68 | } 69 | } 70 | 71 | public ulong TotalCharge 72 | { 73 | get 74 | { 75 | using (this.@lock.GetReaderLock()) 76 | { 77 | return this.usage; 78 | } 79 | } 80 | } 81 | 82 | /// 83 | /// Initializes a new instance of the class. 84 | /// Creates an LRU of the given size. 85 | /// maxEntries is zero, the cache has no limit and it's assumed that eviction is done by the caller. 86 | /// 87 | /// 88 | public LRUCache(int maxEntries, IEqualityComparer comparer, ulong capacity, TimeSpan ttl) 89 | { 90 | this.maxEntries = maxEntries; 91 | this.@lock = new ReaderWriterLockSlim(); 92 | this.lruList = new LinkedList>(); 93 | this.map = new Dictionary>>(comparer); 94 | this.capacity = capacity; 95 | this.ttl = ttl; 96 | } 97 | 98 | public LRUCache(int maxEntries, TimeSpan ttl) 99 | : this(maxEntries, EqualityComparer.Default, 0, ttl) 100 | { 101 | } 102 | 103 | public LRUCache(int maxEntries, IEqualityComparer comparer) 104 | : this(maxEntries, comparer, 0, TimeSpan.MaxValue) 105 | { 106 | } 107 | 108 | public LRUCache(int maxEntries = 0, ulong capacity = 0) 109 | : this(maxEntries, EqualityComparer.Default, capacity, TimeSpan.MaxValue) 110 | { 111 | } 112 | 113 | /// 114 | /// Adds a an element to the cache. 115 | /// 116 | /// The object to use as the key of the element to add. 117 | /// The object to use as the value of the element to add. 118 | /// key is null. 119 | /// Returns true if an eviction occured. 120 | public bool Add(TKey key, TValue value, ulong charge = 0) 121 | { 122 | return this.Add(key, ref value, true, charge); 123 | } 124 | 125 | /// 126 | /// Removes the element with the specified key from the cache. 127 | /// 128 | /// 129 | /// true if the element is successfully removed; otherwise, false. 130 | /// This method also returns false if key was not found. 131 | /// 132 | /// true if the item existed. 133 | public bool Remove(TKey key) 134 | { 135 | if (key == null) 136 | { 137 | throw new ArgumentNullException("key"); 138 | } 139 | 140 | using (this.@lock.GetWriterLock()) 141 | { 142 | LinkedListNode> node; 143 | if (this.map.TryGetValue(key, out node)) 144 | { 145 | this.RemoveElement(node); 146 | return true; 147 | } 148 | 149 | return false; 150 | } 151 | } 152 | 153 | /// 154 | /// Check if a key is in the cache, without updating the recent-ness or deleting it for being stale. 155 | /// 156 | /// 157 | public bool ContainsKey(TKey key) 158 | { 159 | if (key == null) 160 | { 161 | throw new ArgumentNullException("key"); 162 | } 163 | 164 | using (this.@lock.GetReaderLock()) 165 | { 166 | return this.map.ContainsKey(key); 167 | } 168 | } 169 | 170 | /// 171 | /// Gets the value associated with the specified key. 172 | /// 173 | /// The key whose value to get. 174 | /// 175 | /// The value associated with the specified key, if the key is found; 176 | /// otherwise, the default value for the type of the value parameter. 177 | /// 178 | /// true if the item was found. 179 | public bool TryGetValue(TKey key, out TValue value) 180 | { 181 | if (key == null) 182 | { 183 | throw new ArgumentNullException("key"); 184 | } 185 | 186 | using (this.@lock.GetWriterLock()) 187 | { 188 | LinkedListNode> node; 189 | if (this.map.TryGetValue(key, out node)) 190 | { 191 | if (DateTimeOffset.Now.Subtract(node.Value.CreationTime) <= this.ttl) 192 | { 193 | this.lruList.MoveToFront(node); 194 | value = node.Value.Value; 195 | return true; 196 | } 197 | else 198 | { 199 | this.RemoveElement(node); 200 | } 201 | } 202 | 203 | value = default(TValue); 204 | return false; 205 | } 206 | } 207 | 208 | /// 209 | /// Gets the value associated with the specified key. 210 | /// 211 | /// The key whose value to get. 212 | /// 213 | /// If the key is not found, this is the value that will be added and returned. 214 | /// 215 | /// the value associated to the key. 216 | public TValue GetOrAdd(TKey key, Func valueFactory) 217 | { 218 | if (key == null) 219 | { 220 | throw new ArgumentNullException("key"); 221 | } 222 | 223 | if (valueFactory == null) 224 | { 225 | throw new ArgumentNullException("valueFactory"); 226 | } 227 | 228 | TValue outValue; 229 | if (!this.TryGetValue(key, out outValue)) 230 | { 231 | outValue = valueFactory(key); 232 | this.Add(key, ref outValue, false, 0); 233 | } 234 | 235 | return outValue; 236 | } 237 | 238 | public void Clear() 239 | { 240 | using (this.@lock.GetWriterLock()) 241 | { 242 | this.lruList.Clear(); 243 | this.map.Clear(); 244 | } 245 | } 246 | 247 | /// 248 | public IEnumerator> GetEnumerator() 249 | { 250 | using (this.@lock.GetReaderLock()) 251 | { 252 | return this.lruList.Select(e => new KeyValuePair(e.Key, e.Value)).ToList().GetEnumerator(); 253 | } 254 | } 255 | 256 | /// 257 | IEnumerator IEnumerable.GetEnumerator() 258 | { 259 | return this.GetEnumerator(); 260 | } 261 | 262 | /// 263 | public void Dispose() 264 | { 265 | this.@lock.Dispose(); 266 | } 267 | 268 | 269 | 270 | // note: must hold _lock 271 | private void RemoveOldest() 272 | { 273 | var oldestNode = this.lruList.Last; 274 | if (oldestNode != null) 275 | { 276 | this.RemoveElement(oldestNode); 277 | this.ItemEvicted?.Invoke(new KeyValuePair(oldestNode.Value.Key, oldestNode.Value.Value)); 278 | } 279 | } 280 | 281 | // note: must hold _lock 282 | private void RemoveElement(LinkedListNode> element) 283 | { 284 | // Remove using LinkedListNode is an O(1) operation. 285 | this.lruList.Remove(element); 286 | this.map.Remove(element.Value.Key); 287 | this.usage -= element.Value.Charge; 288 | } 289 | 290 | /// 291 | /// Add or update an entry to the LRUCache and put it in the front of the lru list. 292 | /// 293 | /// 294 | /// 295 | /// whether to replace the value if already exist. 296 | /// charge for capacity. 297 | /// 298 | private bool Add(TKey key, ref TValue value, bool replace = true, ulong charge = 0) 299 | { 300 | bool evicted = false; 301 | bool itemLargerThanCapacity = false; 302 | if (key == null) 303 | { 304 | throw new ArgumentNullException("key"); 305 | } 306 | 307 | using (this.@lock.GetWriterLock()) 308 | { 309 | LinkedListNode> node; 310 | 311 | // Check for existing item 312 | if (this.map.TryGetValue(key, out node)) 313 | { 314 | this.lruList.MoveToFront(node); 315 | if (replace) 316 | { 317 | node.Value.Value = value; 318 | } 319 | else 320 | { 321 | value = node.Value.Value; 322 | } 323 | 324 | return false; 325 | } 326 | 327 | if (this.capacity == 0 || charge <= this.capacity) 328 | { 329 | // Add new item 330 | var entry = new Entry { Key = key, Value = value, Charge = charge, CreationTime = DateTimeOffset.Now }; 331 | this.lruList.AddFirst(entry); 332 | this.map[key] = this.lruList.First; 333 | this.usage += charge; 334 | } 335 | else 336 | { 337 | itemLargerThanCapacity = true; 338 | } 339 | 340 | // Verify size not exceeded 341 | while ((this.maxEntries != 0 && this.lruList.Count > this.maxEntries) || (this.capacity != 0 && this.usage > this.capacity)) 342 | { 343 | evicted = true; 344 | this.RemoveOldest(); 345 | } 346 | } 347 | 348 | if (itemLargerThanCapacity) 349 | { 350 | this.ItemOverCapacity?.Invoke(new KeyValuePair(key, value)); 351 | } 352 | 353 | return evicted; 354 | } 355 | 356 | /// 357 | /// Defines a key/value pair that can be set or retrieved. 358 | /// 359 | /// The type of the key. 360 | /// The type of the value. 361 | private class Entry 362 | { 363 | public ulong Charge 364 | { 365 | get; 366 | set; 367 | } 368 | 369 | public DateTimeOffset CreationTime 370 | { 371 | get; 372 | set; 373 | } 374 | 375 | public TEKey Key 376 | { 377 | get; 378 | set; 379 | } 380 | 381 | public TEValue Value 382 | { 383 | get; 384 | set; 385 | } 386 | } 387 | } 388 | } 389 | -------------------------------------------------------------------------------- /src/GroupCache/DiskCache.cs: -------------------------------------------------------------------------------- 1 | // -------------------------------------------------------------------------------------------------------------------- 2 | // 3 | // Copyright (c) Microsoft Corporation. All rights reserved. 4 | // Licensed under the MIT license. See LICENSE file in the project root for full license information. 5 | // 6 | // -------------------------------------------------------------------------------------------------------------------- 7 | 8 | namespace GroupCache 9 | { 10 | using System; 11 | using System.Collections.Concurrent; 12 | using System.Collections.Generic; 13 | using System.Diagnostics; 14 | using System.IO; 15 | using System.Linq; 16 | using System.Threading; 17 | using System.Threading.Tasks; 18 | using Microsoft.VisualStudio.Threading; 19 | 20 | public interface IFileSystem 21 | { 22 | Stream FileOpenRead(string path); 23 | 24 | void FileDelete(string sourcePath, string tmpPath); 25 | 26 | Task WriteAtomicAsync(Func copyAsync, string tmpPath, CancellationToken ct); 27 | 28 | string[] DirectoryGetFiles(string directoryPath); 29 | 30 | void DirectoryCreate(string directoryPath); 31 | 32 | void DirectoryReCreate(string directoryPath); 33 | } 34 | 35 | public class MockFileSystem : IFileSystem 36 | { 37 | private readonly Dictionary> dirs = new Dictionary>(); 38 | private readonly object @lock = new object(); 39 | 40 | /// 41 | public void DirectoryCreate(string directoryPath) 42 | { 43 | lock (this.@lock) 44 | { 45 | this.dirs.Add(directoryPath, new Dictionary()); 46 | } 47 | } 48 | 49 | /// 50 | public string[] DirectoryGetFiles(string directoryPath) 51 | { 52 | lock (this.@lock) 53 | { 54 | return this.dirs[directoryPath].Keys.ToArray(); 55 | } 56 | } 57 | 58 | /// 59 | public void DirectoryReCreate(string directoryPath) 60 | { 61 | lock (this.@lock) 62 | { 63 | this.dirs.Remove(directoryPath); 64 | this.dirs.Add(directoryPath, new Dictionary()); 65 | } 66 | } 67 | 68 | /// 69 | public void FileDelete(string sourcePath, string tmpPath) 70 | { 71 | lock (this.@lock) 72 | { 73 | var directory = Path.GetDirectoryName(sourcePath); 74 | var file = Path.GetFileName(sourcePath); 75 | var dir = this.dirs[directory]; 76 | Debug.Assert(dir.ContainsKey(file)); 77 | dir.Remove(file); 78 | } 79 | } 80 | 81 | /// 82 | public Stream FileOpenRead(string path) 83 | { 84 | lock (this.@lock) 85 | { 86 | var srcFileName = Path.GetFileName(path); 87 | var srcDir = Path.GetDirectoryName(path); 88 | return new MemoryStream(this.dirs[srcDir][srcFileName]); 89 | } 90 | } 91 | 92 | /// 93 | public async Task WriteAtomicAsync(Func copyAsync, string tmpPath, CancellationToken ct) 94 | { 95 | using (var memStream = new MemoryStream()) 96 | { 97 | await copyAsync(memStream, ct).ConfigureAwait(false); 98 | var array = memStream.ToArray(); 99 | lock (this.@lock) 100 | { 101 | var randomPath = this.GenerateRandomFilePath(tmpPath); 102 | var srcFileName = Path.GetFileName(randomPath); 103 | var srcDir = Path.GetDirectoryName(randomPath); 104 | this.dirs[srcDir].Add(srcFileName, array); 105 | return randomPath; 106 | } 107 | } 108 | } 109 | 110 | private bool Exists(string path) 111 | { 112 | lock (this.@lock) 113 | { 114 | var srcFileName = Path.GetFileName(path); 115 | var srcDir = Path.GetDirectoryName(path); 116 | return this.dirs[srcDir].ContainsKey(srcFileName); 117 | } 118 | } 119 | 120 | private string GenerateRandomFilePath(string tmpPath) 121 | { 122 | string filePath; 123 | do 124 | { 125 | filePath = Path.Combine(tmpPath, Guid.NewGuid().ToString()); 126 | } 127 | while (this.Exists(filePath)); 128 | return filePath; 129 | } 130 | } 131 | 132 | public class FileSystem : IFileSystem 133 | { 134 | /// 135 | public Stream FileOpenRead(string path) 136 | { 137 | return File.OpenRead(path); 138 | } 139 | 140 | /// 141 | public void FileDelete(string sourcePath, string tmpPath) 142 | { 143 | File.Delete(sourcePath); 144 | } 145 | 146 | public bool FileExists(string path) 147 | { 148 | return File.Exists(path); 149 | } 150 | 151 | private string GenerateRandomFilePath(string tmpPath) 152 | { 153 | string filePath; 154 | do 155 | { 156 | filePath = Path.Combine(tmpPath, Path.GetRandomFileName()); 157 | } 158 | while (File.Exists(filePath)); 159 | return filePath; 160 | } 161 | 162 | /// 163 | /// 1- create a new file at tmpPath; 164 | /// 2- send data to the operating system kernel for writing to tmpPath; 165 | /// 3- close the file; 166 | /// 4- flush the writing of data to tmpPath; 167 | /// 5- rename tmpPath on top of path. 168 | /// 169 | /// A representing the asynchronous operation. 170 | public async Task WriteAtomicAsync(Func copyAsync, string tmpPath, CancellationToken ct) 171 | { 172 | while (true) 173 | { 174 | try 175 | { 176 | var randomPath = this.GenerateRandomFilePath(tmpPath); 177 | using (var fileStream = File.Create(randomPath)) 178 | { 179 | await copyAsync(fileStream, ct).ConfigureAwait(false); 180 | } 181 | 182 | return randomPath; 183 | } 184 | catch 185 | { 186 | } 187 | } 188 | } 189 | 190 | /// 191 | public string[] DirectoryGetFiles(string directoryPath) 192 | { 193 | return Directory.GetFiles(directoryPath); 194 | } 195 | 196 | /// 197 | public void DirectoryCreate(string directoryPath) 198 | { 199 | if (!Directory.Exists(directoryPath)) 200 | { 201 | Directory.CreateDirectory(directoryPath); 202 | } 203 | } 204 | 205 | /// 206 | public void DirectoryReCreate(string directoryPath) 207 | { 208 | if (Directory.Exists(directoryPath)) 209 | { 210 | // discard all entry 211 | Directory.Delete(directoryPath, true); 212 | } 213 | 214 | Directory.CreateDirectory(directoryPath); 215 | } 216 | } 217 | 218 | // Cache entries have an "in_cache" boolean indicating whether the cache has a 219 | // reference on the entry. 220 | // 221 | // The cache keeps two Dictionary of items in the cache. 222 | // All items in the cache are in one or the other, and never both. 223 | // Items still referenced by clients but erased from the cache are in neither list. 224 | public class DiskCacheEntry : ICacheEntry 225 | { 226 | private readonly DiskCache ownerCache; 227 | 228 | public string Key { get; private set; } 229 | 230 | // file path to the file storing this cache entry data 231 | public string EntryPath { get; internal set; } 232 | 233 | internal int Refs = 0; // References, including cache reference 234 | internal bool InCache = true; // Whether entry is in the cache. 235 | 236 | public DiskCacheEntry(string key, string entryPath, DiskCache owner) 237 | { 238 | Debug.Assert(entryPath != string.Empty, "entryPath should not be empty"); 239 | this.EntryPath = entryPath; 240 | this.ownerCache = owner; 241 | this.Key = key; 242 | } 243 | 244 | /// 245 | /// Read the file from disk each time this is called. 246 | /// 247 | /// 248 | public Stream Value() 249 | { 250 | return this.ownerCache.ReadEntry(this); 251 | } 252 | 253 | /// 254 | public void Ref() 255 | { 256 | Interlocked.Increment(ref this.Refs); 257 | } 258 | 259 | internal int Unref() 260 | { 261 | Debug.Assert(this.Refs > 0, "disk entry should have 1+ reference"); 262 | return Interlocked.Decrement(ref this.Refs); 263 | } 264 | 265 | public void Delete() 266 | { 267 | Debug.Assert(this.Refs <= 0, "refcount must be 0"); 268 | this.ownerCache.DeleteEntry(this); 269 | } 270 | 271 | /// 272 | public Task DisposeAsync() 273 | { 274 | return this.ownerCache.ReleaseAsync(this); 275 | } 276 | } 277 | 278 | public class DiskCache : ICache 279 | { 280 | private readonly SingleFlight concurrentRequest = new SingleFlight(); 281 | public static readonly ICacheEntry EMPTY = new EmptyCacheEntry(); 282 | private readonly AsyncReaderWriterLock rwLock = new AsyncReaderWriterLock(); 283 | 284 | // Store (string -> DiskCacheEntry) mapping for entry that are on disk and not currently referenced by clients, in LRU order 285 | // Entries have refs==1 and in_cache==true. 286 | private readonly LRUCache lruCache; 287 | 288 | // Store (string -> DiskCacheEntry) mapping for entry that are on disk and currently referenced by clients. 289 | // Entries have refs >= 2 and in_cache==true. 290 | private readonly ConcurrentDictionary inUse = new ConcurrentDictionary(); 291 | 292 | // Root cache folder 293 | private readonly string cacheRootPath; 294 | 295 | // Folder for entry that are being written to disk but are not in the cache yet 296 | private readonly string cacheTmpPath; 297 | 298 | private readonly IFileSystem fs; 299 | 300 | // Event trigger when an attempt was made to add an item to the cache 301 | // but the item was larger than the cache maximum size 302 | /// 303 | public event Action ItemOverCapacity; 304 | 305 | public DiskCache(string cacheRootPath, int maxEntryCount, IFileSystem fs = null) 306 | { 307 | this.cacheRootPath = cacheRootPath; 308 | this.cacheTmpPath = Path.Combine(this.cacheRootPath, "tmp"); 309 | this.fs = fs; 310 | if (this.fs == null) 311 | { 312 | this.fs = new FileSystem(); 313 | } 314 | 315 | this.fs.DirectoryCreate(this.cacheRootPath); 316 | this.fs.DirectoryReCreate(this.cacheTmpPath); 317 | 318 | this.lruCache = new LRUCache(maxEntryCount); 319 | this.lruCache.ItemEvicted += (KeyValuePair pair) => this.FinishErase(pair.Key, pair.Value); 320 | this.lruCache.ItemOverCapacity += (kv) => this.ItemOverCapacity?.Invoke(kv.Key); 321 | } 322 | 323 | public async Task ReleaseAsync(DiskCacheEntry entry) 324 | { 325 | int refCount; 326 | 327 | // If InCache == false this is called from FinishErase with _lock already held and cause deadlock 328 | if (Volatile.Read(ref entry.InCache)) 329 | { 330 | using (await this.rwLock.WriteLockAsync()) 331 | { 332 | // entry is in "_inUse" and refcount is between 1 .. N 333 | // Call Unref inside the lock to avoid other thread incrementing concurrently 334 | refCount = entry.Unref(); 335 | if (refCount == 1) 336 | { 337 | // Entry is still in cache but no longer in use. 338 | if (this.inUse.TryRemove(entry.Key, out _)) 339 | { 340 | this.lruCache.Add(entry.Key, entry); 341 | } 342 | } 343 | 344 | if (refCount <= 0) 345 | { 346 | this.inUse.TryRemove(entry.Key, out _); 347 | entry.Delete(); 348 | return; 349 | } 350 | } 351 | } 352 | else 353 | { 354 | // its safe to decrment unref because Entry is not in cache anymore and refcount can only decrease now 355 | if (entry.Refs > 0) 356 | { 357 | refCount = entry.Unref(); 358 | if (refCount == 0) 359 | { 360 | this.inUse.TryRemove(entry.Key, out _); 361 | entry.Delete(); 362 | return; 363 | } 364 | } 365 | } 366 | } 367 | 368 | /// 369 | public async Task GetOrAddAsync(string key, Func valueFactory, ICacheControl cacheControl, CancellationToken ct) 370 | { 371 | using (await this.rwLock.ReadLockAsync()) 372 | { 373 | ICacheEntry found = this.GetInternal(key); 374 | if (!(found is EmptyCacheEntry)) 375 | { 376 | found.Ref(); // this entry remain valid after releasing the lock 377 | return found; 378 | } 379 | } 380 | 381 | using (await this.rwLock.WriteLockAsync()) 382 | { 383 | ICacheEntry found = this.GetInternal(key); 384 | if (!(found is EmptyCacheEntry)) 385 | { 386 | found.Ref(); // this entry remain valid after releasing the lock 387 | return found; 388 | } 389 | 390 | var randomPath = await this.fs.WriteAtomicAsync((sink, cancel) => valueFactory(key, sink, cacheControl), this.cacheTmpPath, ct).ConfigureAwait(false); 391 | var tmpEntry = new DiskCacheEntry(key, randomPath, this); 392 | if (!cacheControl.NoStore) 393 | { 394 | this.SetInternal(key, tmpEntry); 395 | } 396 | 397 | var entry = this.GetInternal(key); 398 | entry.Ref(); 399 | return entry; 400 | } 401 | } 402 | 403 | // Calling thread need to be first lock "_lock" 404 | private ICacheEntry GetInternal(string key) 405 | { 406 | var inUse = this.inUse.TryGetValue(key, out DiskCacheEntry entry); 407 | if (inUse) 408 | { 409 | return entry; 410 | } 411 | 412 | var found = this.lruCache.TryGetValue(key, out entry); 413 | if (found) 414 | { 415 | // Move from _lruCache to _inUse 416 | this.lruCache.Remove(key); 417 | this.inUse.TryAdd(key, entry); 418 | return entry; 419 | } 420 | else 421 | { 422 | return new EmptyCacheEntry(); 423 | } 424 | } 425 | 426 | public async Task GetAsync(string key, CancellationToken ct) 427 | { 428 | using (await this.rwLock.ReadLockAsync()) 429 | { 430 | ICacheEntry entry = this.GetInternal(key); 431 | entry.Ref(); 432 | return entry; 433 | } 434 | } 435 | 436 | /// 437 | public async Task RemoveAsync(string key, CancellationToken ct) 438 | { 439 | using (await this.rwLock.WriteLockAsync()) 440 | { 441 | var found = this.lruCache.TryGetValue(key, out DiskCacheEntry entry); 442 | if (found) 443 | { 444 | this.lruCache.Remove(key); 445 | this.FinishErase(key, entry); 446 | } 447 | 448 | var inUse = this.inUse.TryGetValue(key, out entry); 449 | if (inUse) 450 | { 451 | this.FinishErase(key, entry); 452 | } 453 | } 454 | } 455 | 456 | // Calling thread need to be first take writelock 457 | private bool SetInternal(string key, DiskCacheEntry diskEntry) 458 | { 459 | if (this.inUse.ContainsKey(key)) 460 | { 461 | return false; 462 | } 463 | 464 | if (this.lruCache.ContainsKey(key)) 465 | { 466 | return false; 467 | } 468 | 469 | Volatile.Write(ref diskEntry.InCache, true); 470 | 471 | diskEntry.Ref(); // for the LRU cache's reference. 472 | if (diskEntry.Refs == 1) 473 | { 474 | this.lruCache.Add(key, diskEntry); 475 | } 476 | else if (diskEntry.Refs > 1) 477 | { 478 | this.inUse.TryAdd(key, diskEntry); 479 | } 480 | 481 | Debug.Assert(diskEntry.Refs > 0, "disk entry should have at least 1 reference"); 482 | 483 | return true; 484 | } 485 | 486 | // Entry has already been removed from the hash table 487 | // Finish removing from cache 488 | [System.Diagnostics.CodeAnalysis.SuppressMessage("Usage", "VSTHRD002:Avoid problematic synchronous waits", Justification = "")] 489 | private void FinishErase(string key, DiskCacheEntry entry) 490 | { 491 | if (entry != null) 492 | { 493 | Volatile.Write(ref entry.InCache, false); 494 | entry.DisposeAsync().Wait(); // not inside LRU cache anymore 495 | } 496 | } 497 | 498 | internal void DeleteEntry(DiskCacheEntry diskCacheEntry) 499 | { 500 | var refs = diskCacheEntry.Refs; 501 | Debug.Assert(refs == 0, "disk entry should have 0 reference"); 502 | this.fs.FileDelete(diskCacheEntry.EntryPath, this.cacheTmpPath); 503 | diskCacheEntry.EntryPath = string.Empty; 504 | } 505 | 506 | internal Stream ReadEntry(DiskCacheEntry diskCacheEntry) 507 | { 508 | Debug.Assert(diskCacheEntry.Refs > 0, "disk entry should have at least 1 reference"); 509 | Debug.Assert(diskCacheEntry.EntryPath != string.Empty, "disk entry have been deleted"); 510 | return this.fs.FileOpenRead(diskCacheEntry.EntryPath); 511 | } 512 | } 513 | } 514 | --------------------------------------------------------------------------------