/*
* Copyright (C) 2012 The Guava Authors
*
* Licensed 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 com.google.common.util.concurrent;
import static com.google.common.truth.Truth.assertThat;
import static java.util.Arrays.asList;
import static java.util.concurrent.TimeUnit.SECONDS;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Lists;
import com.google.common.collect.Sets;
import com.google.common.testing.NullPointerTester;
import com.google.common.testing.TestLogHandler;
import com.google.common.util.concurrent.Service.State;
import com.google.common.util.concurrent.ServiceManager.Listener;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import java.util.Set;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.logging.Formatter;
import java.util.logging.Level;
import java.util.logging.LogRecord;
import java.util.logging.Logger;
import junit.framework.TestCase;
/**
* Tests for {@link ServiceManager}.
*
* @author Luke Sandberg
* @author Chris Nokleberg
*/
public class ServiceManagerTest extends TestCase {
private static class NoOpService extends AbstractService {
@Override protected void doStart() {
notifyStarted();
}
@Override protected void doStop() {
notifyStopped();
}
}
/*
* A NoOp service that will delay the startup and shutdown notification for a configurable amount
* of time.
*/
private static class NoOpDelayedService extends NoOpService {
private long delay;
public NoOpDelayedService(long delay) {
this.delay = delay;
}
@Override protected void doStart() {
new Thread() {
@Override public void run() {
Uninterruptibles.sleepUninterruptibly(delay, TimeUnit.MILLISECONDS);
notifyStarted();
}
}.start();
}
@Override protected void doStop() {
new Thread() {
@Override public void run() {
Uninterruptibles.sleepUninterruptibly(delay, TimeUnit.MILLISECONDS);
notifyStopped();
}
}.start();
}
}
private static class FailStartService extends NoOpService {
@Override protected void doStart() {
notifyFailed(new IllegalStateException("start failure"));
}
}
private static class FailRunService extends NoOpService {
@Override protected void doStart() {
super.doStart();
notifyFailed(new IllegalStateException("run failure"));
}
}
private static class FailStopService extends NoOpService {
@Override protected void doStop() {
notifyFailed(new IllegalStateException("stop failure"));
}
}
public void testServiceStartupTimes() {
Service a = new NoOpDelayedService(150);
Service b = new NoOpDelayedService(353);
ServiceManager serviceManager = new ServiceManager(asList(a, b));
serviceManager.startAsync().awaitHealthy();
ImmutableMap<Service, Long> startupTimes = serviceManager.startupTimes();
assertEquals(2, startupTimes.size());
// TODO(kak): Use assertThat(startupTimes.get(a)).isAtLeast(150);
assertTrue(startupTimes.get(a) >= 150);
// TODO(kak): Use assertThat(startupTimes.get(b)).isAtLeast(353);
assertTrue(startupTimes.get(b) >= 353);
}
public void testServiceStartupTimes_selfStartingServices() {
// This tests to ensure that:
// 1. service times are accurate when the service is started by the manager
// 2. service times are recorded when the service is not started by the manager (but they may
// not be accurate).
final Service b = new NoOpDelayedService(353) {
@Override protected void doStart() {
super.doStart();
// This will delay service listener execution at least 150 milliseconds
Uninterruptibles.sleepUninterruptibly(150, TimeUnit.MILLISECONDS);
}
};
Service a = new NoOpDelayedService(150) {
@Override protected void doStart() {
b.startAsync();
super.doStart();
}
};
ServiceManager serviceManager = new ServiceManager(asList(a, b));
serviceManager.startAsync().awaitHealthy();
ImmutableMap<Service, Long> startupTimes = serviceManager.startupTimes();
assertEquals(2, startupTimes.size());
// TODO(kak): Use assertThat(startupTimes.get(a)).isAtLeast(150);
assertTrue(startupTimes.get(a) >= 150);
// Service b startup takes at least 353 millis, but starting the timer is delayed by at least
// 150 milliseconds. so in a perfect world the timing would be 353-150=203ms, but since either
// of our sleep calls can be arbitrarily delayed we should just assert that there is a time
// recorded.
assertThat(startupTimes.get(b)).isNotNull();
}
public void testServiceStartStop() {
Service a = new NoOpService();
Service b = new NoOpService();
ServiceManager manager = new ServiceManager(asList(a, b));
RecordingListener listener = new RecordingListener();
manager.addListener(listener);
assertState(manager, Service.State.NEW, a, b);
assertFalse(manager.isHealthy());
manager.startAsync().awaitHealthy();
assertState(manager, Service.State.RUNNING, a, b);
assertTrue(manager.isHealthy());
assertTrue(listener.healthyCalled);
assertFalse(listener.stoppedCalled);
assertTrue(listener.failedServices.isEmpty());
manager.stopAsync().awaitStopped();
assertState(manager, Service.State.TERMINATED, a, b);
assertFalse(manager.isHealthy());
assertTrue(listener.stoppedCalled);
assertTrue(listener.failedServices.isEmpty());
}
public void testFailStart() throws Exception {
Service a = new NoOpService();
Service b = new FailStartService();
Service c = new NoOpService();
Service d = new FailStartService();
Service e = new NoOpService();
ServiceManager manager = new ServiceManager(asList(a, b, c, d, e));
RecordingListener listener = new RecordingListener();
manager.addListener(listener);
assertState(manager, Service.State.NEW, a, b, c, d, e);
try {
manager.startAsync().awaitHealthy();
fail();
} catch (IllegalStateException expected) {
}
assertFalse(listener.healthyCalled);
assertState(manager, Service.State.RUNNING, a, c, e);
assertEquals(ImmutableSet.of(b, d), listener.failedServices);
assertState(manager, Service.State.FAILED, b, d);
assertFalse(manager.isHealthy());
manager.stopAsync().awaitStopped();
assertFalse(manager.isHealthy());
assertFalse(listener.healthyCalled);
assertTrue(listener.stoppedCalled);
}
public void testFailRun() throws Exception {
Service a = new NoOpService();
Service b = new FailRunService();
ServiceManager manager = new ServiceManager(asList(a, b));
RecordingListener listener = new RecordingListener();
manager.addListener(listener);
assertState(manager, Service.State.NEW, a, b);
try {
manager.startAsync().awaitHealthy();
fail();
} catch (IllegalStateException expected) {
}
assertTrue(listener.healthyCalled);
assertEquals(ImmutableSet.of(b), listener.failedServices);
manager.stopAsync().awaitStopped();
assertState(manager, Service.State.FAILED, b);
assertState(manager, Service.State.TERMINATED, a);
assertTrue(listener.stoppedCalled);
}
public void testFailStop() throws Exception {
Service a = new NoOpService();
Service b = new FailStopService();
Service c = new NoOpService();
ServiceManager manager = new ServiceManager(asList(a, b, c));
RecordingListener listener = new RecordingListener();
manager.addListener(listener);
manager.startAsync().awaitHealthy();
assertTrue(listener.healthyCalled);
assertFalse(listener.stoppedCalled);
manager.stopAsync().awaitStopped();
assertTrue(listener.stoppedCalled);
assertEquals(ImmutableSet.of(b), listener.failedServices);
assertState(manager, Service.State.FAILED, b);
assertState(manager, Service.State.TERMINATED, a, c);
}
public void testToString() throws Exception {
Service a = new NoOpService();
Service b = new FailStartService();
ServiceManager manager = new ServiceManager(asList(a, b));
String toString = manager.toString();
assertThat(toString).contains("NoOpService");
assertThat(toString).contains("FailStartService");
}
public void testTimeouts() throws Exception {
Service a = new NoOpDelayedService(50);
ServiceManager manager = new ServiceManager(asList(a));
manager.startAsync();
try {
manager.awaitHealthy(1, TimeUnit.MILLISECONDS);
fail();
} catch (TimeoutException expected) {
}
manager.awaitHealthy(5, SECONDS); // no exception thrown
manager.stopAsync();
try {
manager.awaitStopped(1, TimeUnit.MILLISECONDS);
fail();
} catch (TimeoutException expected) {
}
manager.awaitStopped(5, SECONDS); // no exception thrown
}
/**
* This covers a case where if the last service to stop failed then the stopped callback would
* never be called.
*/
public void testSingleFailedServiceCallsStopped() {
Service a = new FailStartService();
ServiceManager manager = new ServiceManager(asList(a));
RecordingListener listener = new RecordingListener();
manager.addListener(listener);
try {
manager.startAsync().awaitHealthy();
fail();
} catch (IllegalStateException expected) {
}
assertTrue(listener.stoppedCalled);
}
/**
* This covers a bug where listener.healthy would get called when a single service failed during
* startup (it occurred in more complicated cases also).
*/
public void testFailStart_singleServiceCallsHealthy() {
Service a = new FailStartService();
ServiceManager manager = new ServiceManager(asList(a));
RecordingListener listener = new RecordingListener();
manager.addListener(listener);
try {
manager.startAsync().awaitHealthy();
fail();
} catch (IllegalStateException expected) {
}
assertFalse(listener.healthyCalled);
}
/**
* This covers a bug where if a listener was installed that would stop the manager if any service
* fails and something failed during startup before service.start was called on all the services,
* then awaitStopped would deadlock due to an IllegalStateException that was thrown when trying to
* stop the timer(!).
*/
public void testFailStart_stopOthers() throws TimeoutException {
Service a = new FailStartService();
Service b = new NoOpService();
final ServiceManager manager = new ServiceManager(asList(a, b));
manager.addListener(new Listener() {
@Override public void failure(Service service) {
manager.stopAsync();
}});
manager.startAsync();
manager.awaitStopped(10, TimeUnit.MILLISECONDS);
}
private static void assertState(
ServiceManager manager, Service.State state, Service... services) {
Collection<Service> managerServices = manager.servicesByState().get(state);
for (Service service : services) {
assertEquals(service.toString(), state, service.state());
assertEquals(service.toString(), service.isRunning(), state == Service.State.RUNNING);
assertTrue(managerServices + " should contain " + service, managerServices.contains(service));
}
}
/**
* This is for covering a case where the ServiceManager would behave strangely if constructed
* with no service under management. Listeners would never fire because the ServiceManager was
* healthy and stopped at the same time. This test ensures that listeners fire and isHealthy
* makes sense.
*/
public void testEmptyServiceManager() {
Logger logger = Logger.getLogger(ServiceManager.class.getName());
logger.setLevel(Level.FINEST);
TestLogHandler logHandler = new TestLogHandler();
logger.addHandler(logHandler);
ServiceManager manager = new ServiceManager(Arrays.<Service>asList());
RecordingListener listener = new RecordingListener();
manager.addListener(listener);
manager.startAsync().awaitHealthy();
assertTrue(manager.isHealthy());
assertTrue(listener.healthyCalled);
assertFalse(listener.stoppedCalled);
assertTrue(listener.failedServices.isEmpty());
manager.stopAsync().awaitStopped();
assertFalse(manager.isHealthy());
assertTrue(listener.stoppedCalled);
assertTrue(listener.failedServices.isEmpty());
// check that our NoOpService is not directly observable via any of the inspection methods or
// via logging.
assertEquals("ServiceManager{services=[]}", manager.toString());
assertTrue(manager.servicesByState().isEmpty());
assertTrue(manager.startupTimes().isEmpty());
Formatter logFormatter = new Formatter() {
@Override public String format(LogRecord record) {
return formatMessage(record);
}
};
for (LogRecord record : logHandler.getStoredLogRecords()) {
assertThat(logFormatter.format(record)).doesNotContain("NoOpService");
}
}
/**
* Tests that a ServiceManager can be fully shut down if one of its failure listeners is slow or
* even permanently blocked.
*/
public void testListenerDeadlock() throws InterruptedException {
final CountDownLatch failEnter = new CountDownLatch(1);
final CountDownLatch failLeave = new CountDownLatch(1);
final CountDownLatch afterStarted = new CountDownLatch(1);
Service failRunService = new AbstractService() {
@Override protected void doStart() {
new Thread() {
@Override public void run() {
notifyStarted();
// We need to wait for the main thread to leave the ServiceManager.startAsync call to
// ensure that the thread running the failure callbacks is not the main thread.
Uninterruptibles.awaitUninterruptibly(afterStarted);
notifyFailed(new Exception("boom"));
}
}.start();
}
@Override protected void doStop() {
notifyStopped();
}
};
final ServiceManager manager = new ServiceManager(
Arrays.asList(failRunService, new NoOpService()));
manager.addListener(new ServiceManager.Listener() {
@Override public void failure(Service service) {
failEnter.countDown();
// block until after the service manager is shutdown
Uninterruptibles.awaitUninterruptibly(failLeave);
}
});
manager.startAsync();
afterStarted.countDown();
// We do not call awaitHealthy because, due to races, that method may throw an exception. But
// we really just want to wait for the thread to be in the failure callback so we wait for that
// explicitly instead.
failEnter.await();
assertFalse("State should be updated before calling listeners", manager.isHealthy());
// now we want to stop the services.
Thread stoppingThread = new Thread() {
@Override public void run() {
manager.stopAsync().awaitStopped();
}
};
stoppingThread.start();
// this should be super fast since the only non stopped service is a NoOpService
stoppingThread.join(1000);
assertFalse("stopAsync has deadlocked!.", stoppingThread.isAlive());
failLeave.countDown(); // release the background thread
}
/**
* Catches a bug where when constructing a service manager failed, later interactions with the
* service could cause IllegalStateExceptions inside the partially constructed ServiceManager.
* This ISE wouldn't actually bubble up but would get logged by ExecutionQueue. This obfuscated
* the original error (which was not constructing ServiceManager correctly).
*/
public void testPartiallyConstructedManager() {
Logger logger = Logger.getLogger("global");
logger.setLevel(Level.FINEST);
TestLogHandler logHandler = new TestLogHandler();
logger.addHandler(logHandler);
NoOpService service = new NoOpService();
service.startAsync();
try {
new ServiceManager(Arrays.asList(service));
fail();
} catch (IllegalArgumentException expected) {}
service.stopAsync();
// Nothing was logged!
assertEquals(0, logHandler.getStoredLogRecords().size());
}
public void testPartiallyConstructedManager_transitionAfterAddListenerBeforeStateIsReady() {
// The implementation of this test is pretty sensitive to the implementation :( but we want to
// ensure that if weird things happen during construction then we get exceptions.
final NoOpService service1 = new NoOpService();
// This service will start service1 when addListener is called. This simulates service1 being
// started asynchronously.
Service service2 = new Service() {
final NoOpService delegate = new NoOpService();
@Override public final void addListener(Listener listener, Executor executor) {
service1.startAsync();
delegate.addListener(listener, executor);
}
// Delegates from here on down
@Override public final Service startAsync() {
return delegate.startAsync();
}
@Override public final Service stopAsync() {
return delegate.stopAsync();
}
@Override public final void awaitRunning() {
delegate.awaitRunning();
}
@Override public final void awaitRunning(long timeout, TimeUnit unit)
throws TimeoutException {
delegate.awaitRunning(timeout, unit);
}
@Override public final void awaitTerminated() {
delegate.awaitTerminated();
}
@Override public final void awaitTerminated(long timeout, TimeUnit unit)
throws TimeoutException {
delegate.awaitTerminated(timeout, unit);
}
@Override public final boolean isRunning() {
return delegate.isRunning();
}
@Override public final State state() {
return delegate.state();
}
@Override public final Throwable failureCause() {
return delegate.failureCause();
}
};
try {
new ServiceManager(Arrays.asList(service1, service2));
fail();
} catch (IllegalArgumentException expected) {
assertThat(expected.getMessage()).contains("started transitioning asynchronously");
}
}
/**
* This test is for a case where two Service.Listener callbacks for the same service would call
* transitionService in the wrong order due to a race. Due to the fact that it is a race this
* test isn't guaranteed to expose the issue, but it is at least likely to become flaky if the
* race sneaks back in, and in this case flaky means something is definitely wrong.
*
* <p>Before the bug was fixed this test would fail at least 30% of the time.
*/
public void testTransitionRace() throws TimeoutException {
for (int k = 0; k < 1000; k++) {
List<Service> services = Lists.newArrayList();
for (int i = 0; i < 5; i++) {
services.add(new SnappyShutdownService(i));
}
ServiceManager manager = new ServiceManager(services);
manager.startAsync().awaitHealthy();
manager.stopAsync().awaitStopped(1, TimeUnit.SECONDS);
}
}
/**
* This service will shutdown very quickly after stopAsync is called and uses a background thread
* so that we know that the stopping() listeners will execute on a different thread than the
* terminated() listeners.
*/
private static class SnappyShutdownService extends AbstractExecutionThreadService {
final int index;
final CountDownLatch latch = new CountDownLatch(1);
SnappyShutdownService(int index) {
this.index = index;
}
@Override protected void run() throws Exception {
latch.await();
}
@Override protected void triggerShutdown() {
latch.countDown();
}
@Override protected String serviceName() {
return this.getClass().getSimpleName() + "[" + index + "]";
}
}
public void testNulls() {
ServiceManager manager = new ServiceManager(Arrays.<Service>asList());
new NullPointerTester()
.setDefault(ServiceManager.Listener.class, new RecordingListener())
.testAllPublicInstanceMethods(manager);
}
private static final class RecordingListener extends ServiceManager.Listener {
volatile boolean healthyCalled;
volatile boolean stoppedCalled;
final Set<Service> failedServices = Sets.newConcurrentHashSet();
@Override public void healthy() {
healthyCalled = true;
}
@Override public void stopped() {
stoppedCalled = true;
}
@Override public void failure(Service service) {
failedServices.add(service);
}
}
}