testcontainers / testcontainers/testcontainers-java

[Bug]: duct-tape:1.0.8 contains a Thread Leak

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type/bug
Dominant language
Java
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Merged PRs (30d)
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Description

Module

Core

Testcontainers version

1.20.1

Using the latest Testcontainers version?

Yes

Host OS

MacOS

Host Arch

Apple M3 Pro

Docker version
Client:
 Cloud integration: v1.0.35+desktop.10
 Version:           25.0.3
 API version:       1.44
 Go version:        go1.21.6
 Git commit:        4debf41
 Built:             Tue Feb  6 21:13:26 2024
 OS/Arch:           darwin/arm64
 Context:           desktop-linux

Server: Docker Desktop 4.27.2 (137060)
 Engine:
  Version:          25.0.3
  API version:      1.44 (minimum version 1.24)
  Go version:       go1.21.6
  Git commit:       f417435
  Built:            Tue Feb  6 21:14:22 2024
  OS/Arch:          linux/arm64
  Experimental:     false
 containerd:
  Version:          1.6.28
  GitCommit:        ae07eda36dd25f8a1b98dfbf587313b99c0190bb
 runc:
  Version:          1.1.12
  GitCommit:        v1.1.12-0-g51d5e94
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0
What happened?

Here are my findings.

When using TestContainers in tests, some threads are never stopped which creates Zombie threads.
I'm using the RandomizedTesting framework on my projects and it automatically detects when some threads are still running although everything has been stopped.

The problem is not directly coming from TC but from duct-tape which has been archived 2 years ago by @rnorth.

duct-tape is a dependency of TC: https://github.com/testcontainers/testcontainers-java/blob/0217e78eb986da4e73402288959d05f34b37546f/core/build.gradle#L77C1-L79C6

api ('org.rnorth.duct-tape:duct-tape:1.0.8') {
  exclude(group: 'org.jetbrains', module: 'annotations')
}

The problem in duck tape starts here: https://github.com/rnorth/duct-tape/blob/2a1c5be9f2ef3f16bf036cec8752a170d130b61e/src/main/java/org/rnorth/ducttape/timeouts/Timeouts.java#L15-L25

    private static final ExecutorService EXECUTOR_SERVICE = Executors.newCachedThreadPool(new ThreadFactory() {


        final AtomicInteger threadCounter = new AtomicInteger(0);


        @Override
        public Thread newThread(@NotNull Runnable r) {
            Thread thread = new Thread(r, "ducttape-" + threadCounter.getAndIncrement());
            thread.setDaemon(true);
            return thread;
        }
    });

As soon as you call one of the methods in the Timeouts class, there's one thread which is started and never stopped.

We do call Timeouts in LazyFuture: https://github.com/testcontainers/testcontainers-java/blob/0217e78eb986da4e73402288959d05f34b37546f/core/src/main/java/org/testcontainers/utility/LazyFuture.java#L44-L51 so we end up creating a thread ducttape-1.

Here is a simple test which reproduces the problem:

@RunWith(RandomizedRunner.class)
@TimeoutSuite(millis = 5 * 60 * 1000)
@ThreadLeakScope(ThreadLeakScope.Scope.SUITE)
@ThreadLeakLingering(linger = 10000) // 5 sec lingering
public class ZombieDucttapeDemoIT {

    @Test
    public void testZombie() throws Exception {
        Timeouts.doWithTimeout(1, TimeUnit.SECONDS, () -> {
            System.out.println("Hello world!");
        });
    }
}

When I stop my tests, I can see this:

Hello world!
sept. 16, 2024 5:05:56 PM com.carrotsearch.randomizedtesting.ThreadLeakControl checkThreadLeaks
WARNING: Will linger awaiting termination of 1 leaked thread(s).
sept. 16, 2024 5:06:06 PM com.carrotsearch.randomizedtesting.ThreadLeakControl checkThreadLeaks
SEVERE: 1 thread leaked from SUITE scope at fr.pilato.test.zombie.minio.ZombieDucttapeDemoIT: 
   1) Thread[id=24, name=ducttape-0, state=TIMED_WAITING, group=TGRP-ZombieDucttapeDemoIT]
        at java.base/jdk.internal.misc.Unsafe.park(Native Method)
        at java.base/java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:410)
        at java.base/java.util.concurrent.LinkedTransferQueue$DualNode.await(LinkedTransferQueue.java:452)
        at java.base/java.util.concurrent.SynchronousQueue$Transferer.xferLifo(SynchronousQueue.java:194)
        at java.base/java.util.concurrent.SynchronousQueue.xfer(SynchronousQueue.java:233)
        at java.base/java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:336)
        at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1069)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
        at java.base/java.lang.Thread.run(Thread.java:1583)
sept. 16, 2024 5:06:06 PM com.carrotsearch.randomizedtesting.ThreadLeakControl tryToInterruptAll
INFO: Starting to interrupt leaked threads:
   1) Thread[id=24, name=ducttape-0, state=TIMED_WAITING, group=TGRP-ZombieDucttapeDemoIT]
sept. 16, 2024 5:06:08 PM com.carrotsearch.randomizedtesting.ThreadLeakControl tryToInterruptAll
SEVERE: There are still zombie threads that couldn't be terminated:
   1) Thread[id=24, name=ducttape-0, state=TIMED_WAITING, group=TGRP-ZombieDucttapeDemoIT]
        at java.base/jdk.internal.misc.Unsafe.park(Native Method)
        at java.base/java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:410)
        at java.base/java.util.concurrent.LinkedTransferQueue$DualNode.await(LinkedTransferQueue.java:452)
        at java.base/java.util.concurrent.SynchronousQueue$Transferer.xferLifo(SynchronousQueue.java:194)
        at java.base/java.util.concurrent.SynchronousQueue.xfer(SynchronousQueue.java:233)
        at java.base/java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:336)
        at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1069)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
        at java.base/java.lang.Thread.run(Thread.java:1583)

com.carrotsearch.randomizedtesting.ThreadLeakError: 1 thread leaked from SUITE scope at fr.pilato.test.zombie.minio.ZombieDucttapeDemoIT: 
   1) Thread[id=24, name=ducttape-0, state=TIMED_WAITING, group=TGRP-ZombieDucttapeDemoIT]
        at java.base/jdk.internal.misc.Unsafe.park(Native Method)
        at java.base/java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:410)
        at java.base/java.util.concurrent.LinkedTransferQueue$DualNode.await(LinkedTransferQueue.java:452)
        at java.base/java.util.concurrent.SynchronousQueue$Transferer.xferLifo(SynchronousQueue.java:194)
        at java.base/java.util.concurrent.SynchronousQueue.xfer(SynchronousQueue.java:233)
        at java.base/java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:336)
        at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1069)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
        at java.base/java.lang.Thread.run(Thread.java:1583)

	at __randomizedtesting.SeedInfo.seed([5F166AAD0B3CB2D7]:0)


com.carrotsearch.randomizedtesting.ThreadLeakError: There are still zombie threads that couldn't be terminated:
   1) Thread[id=24, name=ducttape-0, state=TIMED_WAITING, group=TGRP-ZombieDucttapeDemoIT]
        at java.base/jdk.internal.misc.Unsafe.park(Native Method)
        at java.base/java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:410)
        at java.base/java.util.concurrent.LinkedTransferQueue$DualNode.await(LinkedTransferQueue.java:452)
        at java.base/java.util.concurrent.SynchronousQueue$Transferer.xferLifo(SynchronousQueue.java:194)
        at java.base/java.util.concurrent.SynchronousQueue.xfer(SynchronousQueue.java:233)
        at java.base/java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:336)
        at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1069)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
        at java.base/java.lang.Thread.run(Thread.java:1583)

	at __randomizedtesting.SeedInfo.seed([5F166AAD0B3CB2D7]:0)


Process finished with exit code 255

I suggest to do this:

  1. Move the source code of ducttape to test containers
  2. Update the code to provide a way to close the started threads
  3. Ideally automatically close the Threads when container.close() is called.
Relevant log output

No response

Additional Information

The code can be found at https://github.com/dadoonet/demo-ssh-mino/blob/master/src/test/java/fr/pilato/test/zombie/ducctape/ZombieDucttapeDemoIT.java

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with core/build.gradle and core/src/main/java/org/testcontainers/utility/LazyFuture.java, then inspect the linked duct-tape Timeouts.java implementation and reproduce the leak with the provided ZombieDucttapeDemoIT example. Done means the duct-tape executor threads can be closed and the test no longer reports a leaked ducttape thread after cleanup.

Written by the indexing model from the issue text.

Assessment

Tech stack
java
Domain
testing
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Quiet
Clarity
Mostly clear
Newbie friendliness
48/100

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