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Elasticsearch subproject :test:framework
/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.test.disruption;
import org.elasticsearch.common.SuppressForbidden;
import org.elasticsearch.common.unit.TimeValue;
import org.elasticsearch.common.util.concurrent.AbstractRunnable;
import org.elasticsearch.test.InternalTestCluster;
import java.util.Arrays;
import java.util.Random;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicReference;
import java.util.regex.Pattern;
import java.util.stream.Collectors;
/**
* Suspends all threads on the specified node in order to simulate a long gc.
*/
public class LongGCDisruption extends SingleNodeDisruption {
private static final Pattern[] unsafeClasses = new Pattern[]{
// logging has shared JVM locks - we may suspend a thread and block other nodes from doing their thing
Pattern.compile("logging\\.log4j")
};
protected final String disruptedNode;
private Set suspendedThreads;
public LongGCDisruption(Random random, String disruptedNode) {
super(random);
this.disruptedNode = disruptedNode;
}
@Override
public synchronized void startDisrupting() {
if (suspendedThreads == null) {
boolean success = false;
try {
suspendedThreads = ConcurrentHashMap.newKeySet();
final String currentThreadName = Thread.currentThread().getName();
assert currentThreadName.contains("[" + disruptedNode + "]") == false :
"current thread match pattern. thread name: " + currentThreadName + ", node: " + disruptedNode;
// we spawn a background thread to protect against deadlock which can happen
// if there are shared resources between caller thread and and suspended threads
// see unsafeClasses to how to avoid that
final AtomicReference stoppingError = new AtomicReference<>();
final Thread stoppingThread = new Thread(new AbstractRunnable() {
@Override
public void onFailure(Exception e) {
stoppingError.set(e);
}
@Override
protected void doRun() throws Exception {
// keep trying to stop threads, until no new threads are discovered.
while (stopNodeThreads(disruptedNode, suspendedThreads)) {
if (Thread.interrupted()) {
return;
}
}
}
});
stoppingThread.setName(currentThreadName + "[LongGCDisruption][threadStopper]");
stoppingThread.start();
try {
stoppingThread.join(getStoppingTimeoutInMillis());
} catch (InterruptedException e) {
stoppingThread.interrupt(); // best effort to signal stopping
throw new RuntimeException(e);
}
if (stoppingError.get() != null) {
throw new RuntimeException("unknown error while stopping threads", stoppingError.get());
}
if (stoppingThread.isAlive()) {
logger.warn("failed to stop node [{}]'s threads within [{}] millis. Stopping thread stack trace:\n {}"
, disruptedNode, getStoppingTimeoutInMillis(), stackTrace(stoppingThread));
stoppingThread.interrupt(); // best effort;
throw new RuntimeException("stopping node threads took too long");
}
success = true;
} finally {
if (success == false) {
// resume threads if failed
resumeThreads(suspendedThreads);
suspendedThreads = null;
}
}
} else {
throw new IllegalStateException("can't disrupt twice, call stopDisrupting() first");
}
}
private String stackTrace(Thread thread) {
return Arrays.stream(thread.getStackTrace()).map(Object::toString).collect(Collectors.joining("\n"));
}
@Override
public synchronized void stopDisrupting() {
if (suspendedThreads != null) {
resumeThreads(suspendedThreads);
suspendedThreads = null;
}
}
@Override
public void removeAndEnsureHealthy(InternalTestCluster cluster) {
removeFromCluster(cluster);
ensureNodeCount(cluster);
}
@Override
public TimeValue expectedTimeToHeal() {
return TimeValue.timeValueMillis(0);
}
/**
* resolves all threads belonging to given node and suspends them if their current stack trace
* is "safe". Threads are added to nodeThreads if suspended.
*
* returns true if some live threads were found. The caller is expected to call this method
* until no more "live" are found.
*/
@SuppressWarnings("deprecation") // stops/resumes threads intentionally
@SuppressForbidden(reason = "stops/resumes threads intentionally")
protected boolean stopNodeThreads(String node, Set nodeThreads) {
Thread[] allThreads = null;
while (allThreads == null) {
allThreads = new Thread[Thread.activeCount()];
if (Thread.enumerate(allThreads) > allThreads.length) {
// we didn't make enough space, retry
allThreads = null;
}
}
boolean liveThreadsFound = false;
final String nodeThreadNamePart = "[" + node + "]";
for (Thread thread : allThreads) {
if (thread == null) {
continue;
}
String name = thread.getName();
if (name.contains(nodeThreadNamePart)) {
if (thread.isAlive() && nodeThreads.add(thread)) {
liveThreadsFound = true;
logger.trace("stopping thread [{}]", name);
thread.suspend();
// double check the thread is not in a shared resource like logging. If so, let it go and come back..
boolean safe = true;
safe:
for (StackTraceElement stackElement : thread.getStackTrace()) {
String className = stackElement.getClassName();
for (Pattern unsafePattern : getUnsafeClasses()) {
if (unsafePattern.matcher(className).find()) {
safe = false;
break safe;
}
}
}
if (!safe) {
logger.trace("resuming thread [{}] as it is in a critical section", name);
thread.resume();
nodeThreads.remove(thread);
}
}
}
}
return liveThreadsFound;
}
// for testing
protected Pattern[] getUnsafeClasses() {
return unsafeClasses;
}
// for testing
protected long getStoppingTimeoutInMillis() {
return TimeValue.timeValueSeconds(30).getMillis();
}
@SuppressWarnings("deprecation") // stops/resumes threads intentionally
@SuppressForbidden(reason = "stops/resumes threads intentionally")
protected void resumeThreads(Set threads) {
for (Thread thread : threads) {
thread.resume();
}
}
}
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