ITestS3AInputStreamLeakage.java
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.fs.s3a;
import java.lang.ref.WeakReference;
import java.time.Duration;
import org.assertj.core.api.Assertions;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.contract.ContractTestUtils;
import org.apache.hadoop.fs.s3a.impl.streams.ObjectInputStream;
import org.apache.hadoop.fs.statistics.IOStatistics;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.test.GenericTestUtils;
import static org.apache.hadoop.fs.contract.ContractTestUtils.dataset;
import static org.apache.hadoop.fs.s3a.S3ATestUtils.assume;
import static org.apache.hadoop.fs.s3a.S3ATestUtils.skipIfAnalyticsAcceleratorEnabled;
import static org.apache.hadoop.fs.statistics.IOStatisticAssertions.assertThatStatisticCounter;
import static org.apache.hadoop.fs.statistics.StreamStatisticNames.STREAM_LEAKS;
import static org.apache.hadoop.test.GenericTestUtils.LogCapturer.captureLogs;
/**
* Test Stream leakage.
*/
public class ITestS3AInputStreamLeakage extends AbstractS3ATestBase {
/**
* How big a file to create?
*/
public static final int FILE_SIZE = 1024;
public static final byte[] DATASET = dataset(FILE_SIZE, '0', 10);
/**
* Time to wait after a GC/finalize is triggered before looking at the log.
*/
public static final long GC_DELAY = Duration.ofSeconds(1).toMillis();
@BeforeEach
@Override
public void setup() throws Exception {
super.setup();
assume("Stream leak detection not available",
getFileSystem().hasCapability(STREAM_LEAKS));
}
/**
* This test forces a GC of an open file then verifies that the
* log contains the error message.
* <p>
* Care is needed here to ensure that no strong references are held to the
* stream, otherwise: no GC.
* <p>
* It also assumes that {@code System.gc()} will do enough of a treewalk to
* prepare the stream for garbage collection (a weak ref is used to verify
* that it was removed as a reference), and that
* {@code System.runFinalization()} will then
* invoke the finalization.
* <p>
* The finalize code runs its own thread "Finalizer"; this is async enough
* that assertions on log entries only work if there is a pause after
* finalization is triggered and the log is reviewed.
* <p>
* The stream leak counter of the FileSystem is also updated; this
* is verified.
*/
@Test
public void testFinalizer() throws Throwable {
Path path = methodPath();
// Analytics accelerator currently does not support stream leak detection. This work is tracked
// in https://issues.apache.org/jira/browse/HADOOP-19451
skipIfAnalyticsAcceleratorEnabled(getConfiguration(),
"Analytics Accelerator currently does not support leak detection");
final S3AFileSystem fs = getFileSystem();
ContractTestUtils.createFile(fs, path, true, DATASET);
// DO NOT use try-with-resources; this
// test MUST be able to remove all references
// to the stream
FSDataInputStream in = fs.open(path);
try {
Assertions.assertThat(in.hasCapability(STREAM_LEAKS))
.describedAs("Stream leak detection not supported in: %s", in.getWrappedStream())
.isTrue();
Assertions.assertThat(in.read())
.describedAs("first byte read from %s", in)
.isEqualTo(DATASET[0]);
// get a weak ref so that after a GC we can look for it and verify it is gone
WeakReference<ObjectInputStream> wrs =
new WeakReference<>((ObjectInputStream) in.getWrappedStream());
boolean isClassicStream = wrs.get() instanceof S3AInputStream;
final IOStatistics fsStats = fs.getIOStatistics();
final long leaks = fsStats.counters().getOrDefault(STREAM_LEAKS, 0L);
// Capture the logs
GenericTestUtils.LogCapturer logs =
captureLogs(LoggerFactory.getLogger(Logger.ROOT_LOGGER_NAME));
LOG.info("captured log");
// remove strong reference to the stream
in = null;
// force the gc.
System.gc();
// make sure the GC removed the Stream.
Assertions.assertThat(wrs.get())
.describedAs("weak stream reference wasn't GC'd")
.isNull();
// finalize
System.runFinalization();
// finalize is async, so add a brief wait for it to be called.
// without this the log may or may not be empty
Thread.sleep(GC_DELAY);
LOG.info("end of log");
// check the log
logs.stopCapturing();
final String output = logs.getOutput();
LOG.info("output of leak log is {}", output);
Assertions.assertThat(output)
.describedAs("output from the logs during GC")
.contains("Stream not closed") // stream release
.contains(path.toUri().toString()) // path
.contains(Thread.currentThread().getName()) // thread
.contains("testFinalizer"); // stack
// verify that leakages are added to the FS statistics
// for classic stream the counter is 1, but for prefetching
// the count is greater -the inner streams can also
// get finalized while open so increment the leak counter
// multiple times.
assertThatStatisticCounter(fsStats, STREAM_LEAKS)
.isGreaterThanOrEqualTo(leaks + 1);
if (isClassicStream) {
Assertions.assertThat(output)
.describedAs("output from the logs during GC")
.contains("drain or abort reason finalize()"); // stream release
assertThatStatisticCounter(fsStats, STREAM_LEAKS)
.isEqualTo(leaks + 1);
}
} finally {
if (in != null) {
IOUtils.cleanupWithLogger(LOG, in);
}
}
}
}