├── .gitignore ├── src ├── test │ └── java │ │ └── xyz │ │ └── jetdrone │ │ └── hang │ │ └── around │ │ ├── DemoTest.java │ │ └── AsyncAwaitTest.java └── main │ └── java │ └── xyz │ └── jetdrone │ └── hang │ └── around │ └── AsyncAwait.java ├── README.md ├── pom.xml └── LICENSE /.gitignore: -------------------------------------------------------------------------------- 1 | # Compiled class file 2 | *.class 3 | 4 | # Log file 5 | *.log 6 | 7 | # BlueJ files 8 | *.ctxt 9 | 10 | # Mobile Tools for Java (J2ME) 11 | .mtj.tmp/ 12 | 13 | # Package Files # 14 | *.jar 15 | *.war 16 | *.nar 17 | *.ear 18 | *.zip 19 | *.tar.gz 20 | *.rar 21 | 22 | # virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml 23 | hs_err_pid* 24 | -------------------------------------------------------------------------------- /src/test/java/xyz/jetdrone/hang/around/DemoTest.java: -------------------------------------------------------------------------------- 1 | package xyz.jetdrone.hang.around; 2 | 3 | import io.vertx.core.AbstractVerticle; 4 | import io.vertx.core.Promise; 5 | import io.vertx.core.Vertx; 6 | import io.vertx.redis.client.Redis; 7 | import io.vertx.redis.client.RedisOptions; 8 | import org.junit.ClassRule; 9 | import org.junit.Ignore; 10 | import org.junit.Test; 11 | import org.testcontainers.containers.GenericContainer; 12 | 13 | import java.util.concurrent.CountDownLatch; 14 | 15 | import static io.vertx.redis.client.Command.INCR; 16 | import static io.vertx.redis.client.Command.SET; 17 | import static io.vertx.redis.client.Request.cmd; 18 | import static xyz.jetdrone.hang.around.AsyncAwait.*; 19 | 20 | @Ignore 21 | public class DemoTest extends AbstractVerticle { 22 | 23 | @ClassRule 24 | public static final GenericContainer container = new GenericContainer<>("redis:6") 25 | .withExposedPorts(6379); 26 | 27 | @Test 28 | public void testMe() throws InterruptedException { 29 | CountDownLatch latch = new CountDownLatch(1); 30 | Vertx.vertx().deployVerticle(new DemoTest()).onFailure(Throwable::printStackTrace); 31 | latch.await(); 32 | } 33 | 34 | @Override 35 | public void start(Promise start) { 36 | asyncRun(() -> { 37 | Redis redis = Redis.createClient(vertx, new RedisOptions() 38 | .setMaxPoolSize(32) 39 | .setMaxPoolWaiting(128) 40 | .setConnectionString("redis://" + container.getContainerIpAddress() + ":" + container.getFirstMappedPort())); 41 | 42 | System.out.println("Will count calls to: counter"); 43 | await(redis.send(cmd(SET).arg("counter").arg(0))); 44 | 45 | vertx 46 | .createHttpServer() 47 | .requestHandler(async(req -> { 48 | try { 49 | var set = await(redis.send(cmd(INCR).arg("counter"))); 50 | req.response().end(set.toString()); 51 | } catch (RuntimeException e) { 52 | req.response() 53 | .setStatusCode(500) 54 | .end(e.getMessage()); 55 | } 56 | })) 57 | .listen(8000, "0.0.0.0") 58 | .mapEmpty() 59 | .onComplete(start); 60 | }); 61 | } 62 | } 63 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # hang-around 2 | 3 | ## Async Await but for Vert.x 4 | 5 | One of the main pain points of asynchronous programming is that code flow can be hard to read. With the upcoming Java 19 6 | we will see Virtual Threads being added to the JVM. Virtual Threads, unlike regular Threads are not OS Threads and give 7 | us a way to create large amounts of them without worrying that we will exhaust the OS resource. 8 | 9 | This single source file project gives you a rought idea of what you can do to make your asynchronous code more readable. 10 | 11 | The idea isn't new. In fact if you have programmed in JavaScript this will resemble very similar: 12 | 13 | Let's see an example of an HTTP server that will increment a value in REDIS on each call: 14 | 15 | ```java 16 | public class Demo extends AbstractVerticle { 17 | 18 | @Override 19 | public void start(Promise start) { 20 | // wrap this block as a Virtual Thread so we can await (block) at any time 21 | // without interfere with the event loop 22 | asyncRun(() -> { 23 | Redis redis = Redis.createClient( 24 | vertx, 25 | new RedisOptions().setMaxPoolSize(32).setMaxPoolWaiting(128)); 26 | 27 | System.out.println("Will count calls to: counter"); 28 | // look blocking but not the event loop! 29 | await(redis.send(cmd(SET).arg("counter").arg(0))); 30 | 31 | vertx 32 | .createHttpServer() 33 | // handler's are non blocking by nature, so like in JavaScript we just mark then as 34 | // "async()" this will start a new virtual thread and ensure we can block at any time 35 | .requestHandler(async(req -> { 36 | try { 37 | // we block by waiting on the redis response 38 | var set = await(redis.send(cmd(INCR).arg(key))); 39 | // and return the result, no more chains of flatMap(), compose(), onXYZ()... 40 | req.response().end(set.toString()); 41 | } catch (RuntimeException e) { 42 | // exceptions are now also handled as simple try-catch 43 | req.response() 44 | .setStatusCode(500) 45 | .end(e.getMessage()); 46 | } 47 | })) 48 | .listen(8000, "0.0.0.0") 49 | .mapEmpty() 50 | .onComplete(start); 51 | }); 52 | } 53 | } 54 | ``` 55 | 56 | ### But is it fast? 57 | 58 | On my `Intel(R) Core(TM) i7-8650U CPU @ 1.90GHz` I can observe that if I start redis as a test container (which isn't 59 | the best idea for performance testing anyway), This application performs as: 60 | 61 | ``` 62 | ~/Projects/tmp $ wrk -t2 -c100 -d10s http://127.0.0.1:8000 63 | Running 10s test @ http://127.0.0.1:8000 64 | 2 threads and 100 connections 65 | Thread Stats Avg Stdev Max +/- Stdev 66 | Latency 4.62ms 12.54ms 212.71ms 97.60% 67 | Req/Sec 17.23k 5.85k 23.93k 78.79% 68 | 339750 requests in 10.01s, 14.15MB read 69 | Requests/sec: 33932.29 70 | Transfer/sec: 1.41MB 71 | ~/Projects/tmp $ wrk -t2 -c100 -d10s http://127.0.0.1:8000 72 | Running 10s test @ http://127.0.0.1:8000 73 | 2 threads and 100 connections 74 | Thread Stats Avg Stdev Max +/- Stdev 75 | Latency 2.48ms 0.98ms 24.25ms 94.57% 76 | Req/Sec 20.64k 1.90k 23.65k 94.50% 77 | 410919 requests in 10.00s, 17.24MB read 78 | Requests/sec: 41071.70 79 | Transfer/sec: 1.72MB 80 | ~/Projects/tmp $ 81 | ``` 82 | 83 | After a warm-up cycle of 10s, it can deliver `~41071 req/s`. Not bad, right? 84 | -------------------------------------------------------------------------------- /src/test/java/xyz/jetdrone/hang/around/AsyncAwaitTest.java: -------------------------------------------------------------------------------- 1 | package xyz.jetdrone.hang.around; 2 | 3 | import io.vertx.core.Future; 4 | import io.vertx.core.Promise; 5 | import io.vertx.core.impl.VertxInternal; 6 | import io.vertx.ext.unit.Async; 7 | import io.vertx.ext.unit.TestContext; 8 | import io.vertx.ext.unit.junit.RunTestOnContext; 9 | import io.vertx.ext.unit.junit.VertxUnitRunner; 10 | import io.vertx.redis.client.Command; 11 | import io.vertx.redis.client.Redis; 12 | import io.vertx.redis.client.Request; 13 | import org.junit.ClassRule; 14 | import org.junit.Rule; 15 | import org.junit.Test; 16 | import org.junit.runner.RunWith; 17 | import org.testcontainers.containers.GenericContainer; 18 | 19 | import java.util.UUID; 20 | 21 | import static xyz.jetdrone.hang.around.AsyncAwait.*; 22 | 23 | 24 | @RunWith(VertxUnitRunner.class) 25 | public class AsyncAwaitTest { 26 | 27 | @Rule 28 | public RunTestOnContext rule = new RunTestOnContext(); 29 | 30 | @ClassRule 31 | public static final GenericContainer container = new GenericContainer<>("redis:6") 32 | .withExposedPorts(6379); 33 | 34 | @Test 35 | public void testAsyncAwait(TestContext should) { 36 | final Async test = should.async(); 37 | Redis redis = Redis.createClient(rule.vertx(), "redis://" + container.getContainerIpAddress() + ":" + container.getFirstMappedPort()); 38 | asyncRun(() -> { 39 | var set = await(redis.send(Request.cmd(Command.SET).arg("foo").arg("bar"))); 40 | System.out.println(set); 41 | var get = await(redis.send(Request.cmd(Command.GET).arg("foo"))); 42 | System.out.println(get); 43 | test.complete(); 44 | }); 45 | } 46 | 47 | private Future sleep(long millis) { 48 | Promise promise = ((VertxInternal) rule.vertx()).promise(); 49 | rule.vertx() 50 | .setTimer(millis, t -> promise.complete()); 51 | return promise.future(); 52 | } 53 | 54 | @Test 55 | public void testAsyncAwaitOnSleep(TestContext should) { 56 | final Async test = should.async(); 57 | final String value = UUID.randomUUID().toString(); 58 | System.out.println(value); 59 | 60 | Redis redis = Redis.createClient(rule.vertx(), "redis://" + container.getContainerIpAddress() + ":" + container.getFirstMappedPort()); 61 | asyncRun(() -> { 62 | var set = await(redis.send(Request.cmd(Command.SET).arg("foo").arg(value))); 63 | System.out.println(set); 64 | System.out.println("Before sleep"); 65 | await(sleep(500)); 66 | System.out.println("Before after"); 67 | var get = await(redis.send(Request.cmd(Command.GET).arg("foo"))); 68 | System.out.println(get); 69 | System.out.println("Before sleep"); 70 | await(sleep(500)); 71 | System.out.println("Before after"); 72 | test.complete(); 73 | }); 74 | } 75 | 76 | @Test 77 | public void testAsyncAwaitOnSleep2(TestContext should) { 78 | final Async test = should.async(); 79 | asyncRun(() -> { 80 | System.out.println("Before sleep#2"); 81 | await(sleep(5000)); 82 | System.out.println("After after#2"); 83 | test.complete(); 84 | }); 85 | } 86 | 87 | @Test 88 | public void testBlockingSleep(TestContext should) { 89 | final Async test = should.async(); 90 | asyncRun(() -> { 91 | System.out.println("Before sleep#2"); 92 | try { 93 | Thread.sleep(5000L); 94 | } catch (InterruptedException e) { 95 | throw new RuntimeException(e); 96 | } 97 | System.out.println("After after#2"); 98 | test.complete(); 99 | }); 100 | } 101 | } 102 | -------------------------------------------------------------------------------- /src/main/java/xyz/jetdrone/hang/around/AsyncAwait.java: -------------------------------------------------------------------------------- 1 | /* 2 | * Copyright 2015 Red Hat, Inc. 3 | * 4 | * All rights reserved. This program and the accompanying materials 5 | * are made available under the terms of the Eclipse Public License v1.0 6 | * and Apache License v2.0 which accompanies this distribution. 7 | * 8 | * The Eclipse Public License is available at 9 | * http://www.eclipse.org/legal/epl-v10.html 10 | * 11 | * The Apache License v2.0 is available at 12 | * http://www.opensource.org/licenses/apache2.0.php 13 | * 14 | * You may elect to redistribute this code under either of these licenses. 15 | */ 16 | package xyz.jetdrone.hang.around; 17 | 18 | import io.vertx.core.AsyncResult; 19 | import io.vertx.core.Future; 20 | import io.vertx.core.Handler; 21 | import io.vertx.core.impl.logging.Logger; 22 | import io.vertx.core.impl.logging.LoggerFactory; 23 | 24 | import java.util.concurrent.locks.LockSupport; 25 | 26 | public final class AsyncAwait { 27 | 28 | private static final Logger LOG = LoggerFactory.getLogger(AsyncAwait.class); 29 | 30 | public static void asyncRun(Runnable runnable) { 31 | Thread 32 | .ofVirtual() 33 | .name("async-await") 34 | .uncaughtExceptionHandler((thread, err) -> LOG.error("Uncaught Exception @" + thread, err)) 35 | .start(runnable); 36 | } 37 | 38 | public static Handler async(Handler handler) { 39 | return value -> { 40 | final Thread carrier = Thread.currentThread(); 41 | 42 | if (carrier.isVirtual() && "async-await".equals(carrier.getName())) { 43 | // we're inside an async-await block, no need to spawn another one 44 | handler.handle(value); 45 | } else { 46 | Thread 47 | .ofVirtual() 48 | .name("async-await") 49 | .uncaughtExceptionHandler((thread, err) -> LOG.error("Uncaught Exception @" + thread, err)) 50 | .start(() -> handler.handle(value)); 51 | } 52 | }; 53 | } 54 | 55 | public static T await(Future future) { 56 | final Thread carrier = Thread.currentThread(); 57 | 58 | if (!carrier.isVirtual() || !"async-await".equals(carrier.getName())) { 59 | throw new IllegalStateException("async-await thread mismatch"); 60 | } 61 | 62 | return new AsyncAwaitResult<>(carrier, future).get(); 63 | } 64 | 65 | private static final class AsyncAwaitResult implements Handler> { 66 | 67 | private final Thread thread; 68 | private AsyncResult ref; 69 | 70 | AsyncAwaitResult(Thread thread, Future future) { 71 | this.thread = thread; 72 | future.onComplete(this); 73 | } 74 | 75 | @Override 76 | public void handle(AsyncResult event) { 77 | this.ref = event; 78 | LockSupport.unpark(thread); 79 | } 80 | 81 | public T get() { 82 | LockSupport.park(); 83 | // several things could lead to an unpark 84 | 85 | // 1. the thread was interrupted 86 | if (Thread.interrupted()) { 87 | // this could be problematic as the result has not been handled yet 88 | throw new IllegalStateException("async-await thread was interrupted"); 89 | } 90 | 91 | // 1. unpark was called 92 | if (ref.succeeded()) { 93 | return ref.result(); 94 | } else { 95 | Throwable cause = ref.cause(); 96 | // throw as-is 97 | if (cause instanceof RuntimeException) { 98 | throw (RuntimeException) cause; 99 | } 100 | // will wrap exoteric exceptions 101 | throw new RuntimeException(cause); 102 | } 103 | } 104 | } 105 | 106 | } 107 | -------------------------------------------------------------------------------- /pom.xml: -------------------------------------------------------------------------------- 1 | 2 | 5 | 6 | 4.0.0 7 | 8 | 9 | org.sonatype.oss 10 | oss-parent 11 | 9 12 | 13 | 14 | xyz.jetdrone 15 | hang-around 16 | 0.0.1 17 | 18 | jar 19 | 20 | async-await 21 | async-await but for vert.x 22 | 23 | 24 | https://github.com/pmlopes/hang-around/issues 25 | GitHub Issues 26 | 27 | 28 | 29 | https://github.com/pmlopes/hang-around 30 | scm:git:git://github.com/pmlopes/hang-around.git 31 | scm:git:git@github.com:pmlopes/hang-around.git 32 | 33 | 34 | 35 | 36 | Apache License, Version 2.0 37 | repo 38 | http://www.apache.org/licenses/LICENSE-2.0.html 39 | 40 | 41 | 42 | 43 | 4.3.1 44 | 19 45 | 19 46 | 19 47 | UTF-8 48 | 49 | 50 | 51 | 52 | io.vertx 53 | vertx-core 54 | ${vertx.version} 55 | 56 | 57 | io.vertx 58 | vertx-unit 59 | ${vertx.version} 60 | test 61 | 62 | 63 | junit 64 | junit 65 | 4.13.2 66 | test 67 | 68 | 69 | org.testcontainers 70 | testcontainers 71 | 1.15.2 72 | test 73 | 74 | 75 | io.vertx 76 | vertx-redis-client 77 | ${vertx.version} 78 | test 79 | 80 | 81 | 82 | 83 | 84 | 85 | org.apache.maven.plugins 86 | maven-compiler-plugin 87 | 3.10.1 88 | 89 | 19 90 | --enable-preview 91 | 92 | 93 | 94 | org.apache.maven.plugins 95 | maven-surefire-plugin 96 | 3.0.0-M4 97 | 98 | --enable-preview 99 | 100 | 101 | 102 | com.amashchenko.maven.plugin 103 | gitflow-maven-plugin 104 | 1.7.0 105 | 106 | false 107 | 108 | main 109 | develop 110 | feature/ 111 | release/ 112 | hotfix/ 113 | support/ 114 | 115 | 116 | 117 | 118 | 119 | 120 | 121 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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