├── .travis.yml
├── LICENSE
├── README.md
├── capped.go
├── capped_test.go
├── example_test.go
├── interface.go
├── interface_test.go
├── leaky.go
├── leaky_test.go
└── script
    └── test


/.travis.yml:
--------------------------------------------------------------------------------
 1 | language: go
 2 | go:       1.6
 3 | 
 4 | services:
 5 |   - mongodb
 6 | 
 7 | branches:
 8 |   only:
 9 |     - master
10 | 
11 | env:
12 |   - MONGO_HOST=127.0.0.1
13 | 
14 | script: script/test
15 | 


--------------------------------------------------------------------------------
/LICENSE:
--------------------------------------------------------------------------------
 1 | The MIT License (MIT)
 2 | 
 3 | Copyright (c) 2016 Visual Supply, Co.
 4 | 
 5 | Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 6 | 
 7 | The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 8 | 
 9 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
10 | 


--------------------------------------------------------------------------------
/README.md:
--------------------------------------------------------------------------------
  1 | ## ***** DEPRECATION NOTICE ******
  2 | The mongo library that this project depends on has been deprecated ([mgo](https://github.com/globalsign/mgo)), in favor of the 
  3 | [official driver released by mongodb](https://github.com/mongodb/mongo-go-driver). The official driver includes an internal
  4 | mongo connection pool by default, which obviates this library.
  5 | 
  6 | 
  7 | # mgopool<br> [![GoDoc](https://godoc.org/github.com/vsco/mgopool?status.svg)](https://godoc.org/github.com/vsco/mgopool) [![Build Status](https://travis-ci.org/vsco/mgopool.svg?branch=master)](https://travis-ci.org/vsco/mgopool)
  8 | 
  9 | Package mgopool provides buffer implementations around [mgo.Session (v2)][mgo].
 10 | 
 11 | ```
 12 | go get github.com/globalsign/mgo
 13 | go get github.com/vsco/mgopool
 14 | ```
 15 | 
 16 | With mgo, an initial session is created with the server, and then either a [Copy][Session.Copy] or [Clone][Session.Clone]
 17 | of that initial session is used for each unit of work (HTTP request handler, worker loop, etc.), which is
 18 | [closed][Session.Close] upon completion. This allows mgo to efficiently manage a pool of sockets between those sessions;
 19 | however, it also results in the underlying sockets to constantly log in and out of the Mongo cluster.
 20 | 
 21 | mgopool avoids this issue by creating a Pool of copies from the initial session, storing them in a free list. Work units
 22 | request an existing copy (or one is created if it doesn't exist) and then return it to the pool on completion. Both a
 23 | leaky and capped version of the Pool is available, depending on need.
 24 | 
 25 | ## Example Usage
 26 | 
 27 | ```go
 28 | func Example() {
 29 |   // create the initial mgo.Session, defer closing it
 30 |   initial, _ := mgo.Dial("127.0.0.1")
 31 |   defer initial.Close()
 32 | 
 33 |   // create a new leaky pool with size of 3
 34 |   pool := mgopool.NewLeaky(initial, 3)
 35 |   defer pool.Close()
 36 | 
 37 |   wg := sync.WaitGroup{}
 38 | 
 39 |   // create a few workers to utilize the sessions in the pool
 40 |   for i := 0; i < 3; i++ {
 41 |     wg.Add(1)
 42 | 
 43 |     go func() {
 44 |       for j := 0; j < 2; j++ {
 45 |         // get a session from the pool
 46 |         session := pool.Get()
 47 | 
 48 |         // do something with that session, refresh it if there is an error
 49 |         if err := doSomething(session); err != nil {
 50 |           session.Refresh()
 51 |         }
 52 | 
 53 |         // return the session to the pool
 54 |         pool.Put(session)
 55 |       }
 56 |       wg.Done()
 57 |     }()
 58 |   }
 59 | 
 60 |   // wait for the workers to complete
 61 |   wg.Wait()
 62 | 
 63 |   // Output:
 64 |   // foobar
 65 |   // foobar
 66 |   // foobar
 67 |   // foobar
 68 |   // foobar
 69 |   // foobar
 70 | }
 71 | 
 72 | func doSomething(s *mgo.Session) error {
 73 |   fmt.Println("foobar")
 74 |   return s.Ping()
 75 | }
 76 | ```
 77 | 
 78 | [mgo]:           https://godoc.org/github.com/globalsign/mgo
 79 | [Session.Copy]:  https://godoc.org/github.com/globalsign/mgo#Session.Copy
 80 | [Session.Clone]: https://godoc.org/github.com/globalsign/mgo#Session.Clone
 81 | [Session.Close]: https://godoc.org/github.com/globalsign/mgo#Session.Close
 82 | 
 83 | ## Testing
 84 | 
 85 | Testing mgopool requires a running Mongo cluster. The default Mongo host is used (`127.0.0.1:27017`) and
 86 | can be overridden by setting the `MONGO_HOST` env variable. Execute the tests with the following command from the project root:
 87 | 
 88 | ```sh
 89 | script/test
 90 | ```
 91 | 
 92 | ## License
 93 | 
 94 | The MIT License (MIT)
 95 | 
 96 | Copyright (c) 2016 Visual Supply, Co.
 97 | 
 98 | Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 99 | 
100 | The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
101 | 
102 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
103 | 


--------------------------------------------------------------------------------
/capped.go:
--------------------------------------------------------------------------------
 1 | package mgopool
 2 | 
 3 | import mgo "github.com/globalsign/mgo"
 4 | 
 5 | type capped struct {
 6 | 	pool   Pool
 7 | 	leases chan struct{}
 8 | }
 9 | 
10 | // NewCapped creates a capped Pool of sessions copied from initial. Get on a capped Pool will block after size sessions
11 | // have been retrieved until one is Put back in.
12 | func NewCapped(initial *mgo.Session, size int) Pool {
13 | 	return &capped{
14 | 		pool:   NewLeaky(initial, size),
15 | 		leases: make(chan struct{}, size),
16 | 	}
17 | }
18 | 
19 | func (p *capped) Get() *mgo.Session {
20 | 	p.leases <- struct{}{}
21 | 	return p.pool.Get()
22 | }
23 | 
24 | func (p *capped) Put(s *mgo.Session) {
25 | 	select {
26 | 	case <-p.leases:
27 | 	default:
28 | 		//if leases is empty, continue anyways
29 | 	}
30 | 
31 | 	p.pool.Put(s)
32 | }
33 | 
34 | func (p *capped) Close() {
35 | 	close(p.leases)
36 | 	p.pool.Close()
37 | }
38 | 
39 | func (p *capped) Used() int {
40 | 	return p.pool.Used()
41 | }
42 | 
43 | var _ Pool = &capped{}
44 | 


--------------------------------------------------------------------------------
/capped_test.go:
--------------------------------------------------------------------------------
  1 | package mgopool
  2 | 
  3 | import (
  4 | 	"testing"
  5 | 
  6 | 	"time"
  7 | 
  8 | 	mgo "github.com/globalsign/mgo"
  9 | 	"github.com/stretchr/testify/assert"
 10 | )
 11 | 
 12 | func TestCapped_Get(t *testing.T) {
 13 | 	orig := session(t)
 14 | 	defer orig.Close()
 15 | 	p := NewCapped(orig, 1)
 16 | 	defer p.Close()
 17 | 
 18 | 	expected := p.Get()
 19 | 	var actual *mgo.Session
 20 | 
 21 | 	done := make(chan struct{})
 22 | 	go func() {
 23 | 		actual = p.Get()
 24 | 		close(done)
 25 | 	}()
 26 | 
 27 | 	p.Put(expected)
 28 | 
 29 | 	select {
 30 | 	case <-done:
 31 | 	case <-time.NewTimer(time.Millisecond * 10).C:
 32 | 		t.Fatal("capped bucket never unblocked")
 33 | 	}
 34 | 
 35 | 	assert.Equal(t, expected, actual)
 36 | }
 37 | 
 38 | func TestCapped_Put(t *testing.T) {
 39 | 	orig := session(t)
 40 | 	defer orig.Close()
 41 | 	p := NewCapped(orig, 1)
 42 | 	defer p.Close()
 43 | 
 44 | 	expected := p.Get()
 45 | 
 46 | 	p.Put(expected)
 47 | 	p.Put(orig.Copy())
 48 | 
 49 | 	actual := p.Get()
 50 | 	assert.Equal(t, expected, actual)
 51 | 
 52 | 	done := make(chan struct{})
 53 | 	go func() {
 54 | 		actual = p.Get()
 55 | 		close(done)
 56 | 	}()
 57 | 
 58 | 	p.Put(expected)
 59 | 
 60 | 	select {
 61 | 	case <-done:
 62 | 	case <-time.NewTimer(time.Millisecond * 10).C:
 63 | 		t.Fatal("capped bucket never unblocked")
 64 | 	}
 65 | 
 66 | 	assert.Equal(t, expected, actual)
 67 | }
 68 | 
 69 | func TestCapped_Close(t *testing.T) {
 70 | 	orig := session(t)
 71 | 	defer orig.Close()
 72 | 	p := NewCapped(orig, 1)
 73 | 
 74 | 	s := p.Get()
 75 | 
 76 | 	p.Put(s)
 77 | 	p.Close()
 78 | 
 79 | 	assert.Panics(t, func() {
 80 | 		p.Get()
 81 | 	})
 82 | 
 83 | 	assert.Panics(t, func() {
 84 | 		p.Put(s)
 85 | 	})
 86 | 
 87 | 	assert.Panics(t, func() {
 88 | 		s.Copy()
 89 | 	})
 90 | 
 91 | 	assert.NotPanics(t, func() {
 92 | 		orig.Copy().Close()
 93 | 	})
 94 | }
 95 | 
 96 | func TestCapped_Used(t *testing.T) {
 97 | 	orig := session(t)
 98 | 	defer orig.Close()
 99 | 
100 | 	p := NewCapped(orig, 1)
101 | 	defer p.Close()
102 | 	assert.Equal(t, 0, p.Used())
103 | 
104 | 	leak := p.Get()
105 | 	assert.Equal(t, 1, p.Used())
106 | 
107 | 	p.Put(leak)
108 | 	assert.Equal(t, 0, p.Used())
109 | }
110 | 


--------------------------------------------------------------------------------
/example_test.go:
--------------------------------------------------------------------------------
 1 | package mgopool
 2 | 
 3 | import (
 4 | 	"os"
 5 | 
 6 | 	"sync"
 7 | 
 8 | 	"fmt"
 9 | 
10 | 	"github.com/globalsign/mgo"
11 | )
12 | 
13 | func Example() {
14 | 	host := os.Getenv("MONGO_HOST")
15 | 
16 | 	// create the initial mgo.Session, defer closing it
17 | 	initial, _ := mgo.Dial(host)
18 | 	defer initial.Close()
19 | 
20 | 	// create a new leaky pool with size of 3
21 | 	pool := NewLeaky(initial, 3)
22 | 	defer pool.Close()
23 | 
24 | 	wg := sync.WaitGroup{}
25 | 
26 | 	// create a few workers to utilize the sessions in the pool
27 | 	for i := 0; i < 3; i++ {
28 | 		wg.Add(1)
29 | 
30 | 		go func() {
31 | 			for j := 0; j < 2; j++ {
32 | 				// get a session from the pool
33 | 				session := pool.Get()
34 | 
35 | 				// do something with that session, refresh it if there is an error
36 | 				if err := doSomething(session); err != nil {
37 | 					session.Refresh()
38 | 				}
39 | 
40 | 				// return the session to the pool
41 | 				pool.Put(session)
42 | 			}
43 | 			wg.Done()
44 | 		}()
45 | 	}
46 | 
47 | 	// wait for the workers to complete
48 | 	wg.Wait()
49 | 
50 | 	// Output:
51 | 	// foobar
52 | 	// foobar
53 | 	// foobar
54 | 	// foobar
55 | 	// foobar
56 | 	// foobar
57 | }
58 | 
59 | func doSomething(s *mgo.Session) error {
60 | 	fmt.Println("foobar")
61 | 	return s.Ping()
62 | }
63 | 


--------------------------------------------------------------------------------
/interface.go:
--------------------------------------------------------------------------------
 1 | // Package mgopool provides buffer implementations around mgo.Session (v2).
 2 | //
 3 | // With mgo, an initial session is created with the server, and then either a copy or clone of that initial session is
 4 | // used for each unit of work (HTTP request handler, worker loop, etc.), which is closed upon completion. This allows
 5 | // mgo to efficiently manage a pool of sockets between those sessions; however, this results in the underlying sockets
 6 | // to constantly log in and out of the Mongo cluster.
 7 | //
 8 | // mgopool avoids this issue by creating a Pool of copies from the initial session, storing them in a free list. Work
 9 | // units request an existing copy (or one is created if it doesn't exist) and then return it to the pool on completion.
10 | // Both a leaky and capped version of the Pool is available, depending on need.
11 | package mgopool
12 | 
13 | import mgo "github.com/globalsign/mgo"
14 | 
15 | // The Pool interface describes the mechanisms for retrieving and releasing mgo.Sessions. The pool should be used in
16 | // place of calling Copy/Clone and Close on mgo.Session directly.
17 | type Pool interface {
18 | 	// Get returns a *mgo.Session from the Pool. If there are no free sessions, a new one is copied from the initial
19 | 	// Session. If the Pool is capped and all sessions have been retrieved, Get will block until a session is returned to
20 | 	// with Put.
21 | 	Get() *mgo.Session
22 | 
23 | 	// Put releases an *mgo.Session back into the Pool. Only healthy sessions (or nil) should be returned to the pool. If
24 | 	// a session is errors, Refresh should be called before releasing it to the Pool.
25 | 	Put(*mgo.Session)
26 | 
27 | 	// Used is the total number of outstanding leases associated with this Pool.
28 | 	// Note, this is just a snapshot of the used leased at the time this method was invoked
29 | 	Used() int
30 | 
31 | 	// Close drains the Pool, closing all held sessions. The initial session is not closed by this method. Calling Get or
32 | 	// Put on a closed pool will result in a panic.
33 | 	Close()
34 | }
35 | 


--------------------------------------------------------------------------------
/interface_test.go:
--------------------------------------------------------------------------------
 1 | package mgopool
 2 | 
 3 | import (
 4 | 	"os"
 5 | 	"testing"
 6 | 
 7 | 	"github.com/globalsign/mgo"
 8 | )
 9 | 
10 | func session(t *testing.T) *mgo.Session {
11 | 	host := os.Getenv("MONGO_HOST")
12 | 
13 | 	sess, err := mgo.Dial(host)
14 | 	if err != nil {
15 | 		t.Fatalf("%v", err)
16 | 	}
17 | 
18 | 	return sess
19 | }
20 | 


--------------------------------------------------------------------------------
/leaky.go:
--------------------------------------------------------------------------------
 1 | package mgopool
 2 | 
 3 | import (
 4 | 	"sync/atomic"
 5 | 
 6 | 	mgo "github.com/globalsign/mgo"
 7 | )
 8 | 
 9 | type leaky struct {
10 | 	base     *mgo.Session
11 | 	freeList chan *mgo.Session
12 | 	used     int32
13 | }
14 | 
15 | // NewLeaky creates a leaky Pool of sessions copied from initial. A maximum of size sessions will be held in the free
16 | // list, but the Pool will not block calls to Get. Releasing excess sessions to the pool are automatically Closed and
17 | // removed.
18 | func NewLeaky(initial *mgo.Session, size int) Pool {
19 | 	return &leaky{
20 | 		base:     initial.Clone(),
21 | 		freeList: make(chan *mgo.Session, size),
22 | 		used:     0,
23 | 	}
24 | 
25 | }
26 | 
27 | func (p *leaky) Get() *mgo.Session {
28 | 	atomic.AddInt32(&p.used, 1)
29 | 	select {
30 | 	case s, more := <-p.freeList:
31 | 		if s == nil || !more {
32 | 			panic("pool has been closed")
33 | 		}
34 | 		return s
35 | 	default:
36 | 		// if freeList is empty, Copy a new session
37 | 		return p.base.Copy()
38 | 	}
39 | }
40 | 
41 | func (p *leaky) Put(s *mgo.Session) {
42 | 	atomic.AddInt32(&p.used, -1)
43 | 	if s == nil {
44 | 		return
45 | 	}
46 | 
47 | 	select {
48 | 	case p.freeList <- s:
49 | 	default:
50 | 		// if freeList is full, close and discard the session
51 | 		s.Close()
52 | 	}
53 | }
54 | 
55 | func (p *leaky) Close() {
56 | 	close(p.freeList)
57 | 	for s := range p.freeList {
58 | 		s.Close()
59 | 	}
60 | 	p.base.Close()
61 | }
62 | 
63 | func (p *leaky) Used() int {
64 | 	return int(p.used)
65 | }
66 | 
67 | var _ Pool = &leaky{}
68 | 


--------------------------------------------------------------------------------
/leaky_test.go:
--------------------------------------------------------------------------------
 1 | package mgopool
 2 | 
 3 | import (
 4 | 	"testing"
 5 | 
 6 | 	"github.com/stretchr/testify/assert"
 7 | )
 8 | 
 9 | func TestLeaky_Get(t *testing.T) {
10 | 	orig := session(t)
11 | 	defer orig.Close()
12 | 	p := NewLeaky(orig, 1)
13 | 	defer p.Close()
14 | 
15 | 	s := p.Get()
16 | 	assert.NotNil(t, s)
17 | 
18 | 	p.Put(s)
19 | 	next := p.Get()
20 | 	assert.Equal(t, s, next)
21 | }
22 | 
23 | func TestLeaky_Put(t *testing.T) {
24 | 	orig := session(t)
25 | 	defer orig.Close()
26 | 	p := NewLeaky(orig, 1)
27 | 	defer p.Close()
28 | 
29 | 	leak := p.Get()
30 | 
31 | 	p.Put(p.Get())
32 | 	p.Put(leak)
33 | 
34 | 	actual := p.Get()
35 | 	assert.NotEqual(t, leak, actual)
36 | 
37 | 	p.Put(nil)
38 | 	actual = p.Get()
39 | 
40 | 	assert.NotNil(t, actual)
41 | }
42 | 
43 | func TestLeak_Close(t *testing.T) {
44 | 	orig := session(t)
45 | 	defer orig.Close()
46 | 	p := NewLeaky(orig, 1)
47 | 
48 | 	s := p.Get()
49 | 
50 | 	p.Put(s)
51 | 	p.Close()
52 | 
53 | 	assert.Panics(t, func() {
54 | 		p.Get()
55 | 	})
56 | 
57 | 	assert.Panics(t, func() {
58 | 		p.Put(s)
59 | 	})
60 | 
61 | 	assert.Panics(t, func() {
62 | 		s.Copy()
63 | 	})
64 | 
65 | 	assert.NotPanics(t, func() {
66 | 		orig.Copy().Close()
67 | 	})
68 | }
69 | 
70 | func TestLeaky_Used(t *testing.T) {
71 | 	orig := session(t)
72 | 	defer orig.Close()
73 | 
74 | 	p := NewLeaky(orig, 1)
75 | 	defer p.Close()
76 | 	assert.Equal(t, 0, p.Used())
77 | 
78 | 	leak := p.Get()
79 | 	assert.Equal(t, 1, p.Used())
80 | 
81 | 	p.Put(p.Get())
82 | 	p.Put(leak)
83 | 	assert.Equal(t, 0, p.Used())
84 | }
85 | 


--------------------------------------------------------------------------------
/script/test:
--------------------------------------------------------------------------------
 1 | #!/usr/bin/env bash
 2 | set -e
 3 | 
 4 | : ${MONGO_HOST:=127.0.0.1}
 5 | 
 6 | test -z "$(gofmt -l -w .       | tee /dev/stderr)"
 7 | test -z "$(golint ./...        | tee /dev/stderr)"
 8 | test -z "$(go tool vet -tests . | tee /dev/stderr)"
 9 | 
10 | go test -v -race -cover ./...
11 | 


--------------------------------------------------------------------------------