[HTTPCORE-631] HttpAsyncClient 5.0 file descriptor leak

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 5.0
• Fix Version/s: 5.0.1
• Component/s: HttpCore NIO
• Assignee: Unassigned
• Reporter: Ben Tindall
• Created: 01/May/20 10:01
• Updated: 05/May/20 15:17
• Resolved: 04/May/20 16:35

Description

It seems that HttpAsyncClient doesn't close all its file descriptors with the close() operation. Consider the following test:

    @Test
    public void leakApache() throws Exception {
        for (int i = 0; i < 10000; i++) {
            CloseableHttpAsyncClient client = null;
            try {
                client = HttpAsyncClientBuilder.create().build();
                System.out.println(i);
            } catch (Throwable e) {
                e.printStackTrace();
            } finally {
                if (client != null)
                    client.close();
            }
            Thread.sleep(10);
        }

        Thread.sleep(300000);
    }
 

After around 280 iterations I start seeing this error message (java.io.IOException: Too many open files):

java.lang.IllegalStateException: Unexpected failure opening I/O selector
 at org.apache.hc.core5.reactor.AbstractSingleCoreIOReactor.<init>(AbstractSingleCoreIOReactor.java:60)
 at org.apache.hc.core5.reactor.SingleCoreIOReactor.<init>(SingleCoreIOReactor.java:81)
 at org.apache.hc.core5.reactor.DefaultConnectingIOReactor.<init>(DefaultConnectingIOReactor.java:71)
 at org.apache.hc.client5.http.impl.async.HttpAsyncClientBuilder.build(HttpAsyncClientBuilder.java:924)
 at com.mimecast.micro.rest.BenTest.leakApache(BenTest.java:77)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:498)
 at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
 at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
 at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
 at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
 at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
 at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
 at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
 at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
 at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
 at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
 at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
 at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
 at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
 at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
 at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
 at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
 at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)
 at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)
 Caused by: java.io.IOException: Too many open files
 at sun.nio.ch.IOUtil.makePipe(Native Method)
 at sun.nio.ch.KQueueSelectorImpl.<init>(KQueueSelectorImpl.java:84)
 at sun.nio.ch.KQueueSelectorProvider.openSelector(KQueueSelectorProvider.java:42)
 at java.nio.channels.Selector.open(Selector.java:227)
 at org.apache.hc.core5.reactor.AbstractSingleCoreIOReactor.<init>(AbstractSingleCoreIOReactor.java:58)
 ... 26 more 

If I run lsof i see around 10k files. These files do not get released until the whole test closes.

Is there something I'm missing?

Thanks,
Ben