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trohrmann pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/flink.git
commit ccf27ff845836d74bcb94a9b5baf4bc171ea2ff3
Author: Till Rohrmann <trohrm...@apache.org>
AuthorDate: Thu Mar 7 17:28:33 2019 +0100
[FLINK-11855] Fix race condition in
EmbeddedLeaderService#GrantLeadershipCall
Fix the race condition between executing
EmbeddedLeaderService#GrantLeadershipCall
and a concurrent shutdown of the leader service by making
GrantLeadershipCall not
accessing mutable state outside of a lock.
This closes #7935.
---
.../nonha/embedded/EmbeddedLeaderService.java | 46 +++++----
.../nonha/embedded/EmbeddedHaServicesTest.java | 44 +--------
.../nonha/embedded/EmbeddedLeaderServiceTest.java | 103 +++++++++++++++++++++
.../nonha/embedded/TestingLeaderContender.java | 87 +++++++++++++++++
4 files changed, 221 insertions(+), 59 deletions(-)
diff --git
a/flink-runtime/src/main/java/org/apache/flink/runtime/highavailability/nonha/embedded/EmbeddedLeaderService.java
b/flink-runtime/src/main/java/org/apache/flink/runtime/highavailability/nonha/embedded/EmbeddedLeaderService.java
index 97b80dc..e3e98e1 100644
---
a/flink-runtime/src/main/java/org/apache/flink/runtime/highavailability/nonha/embedded/EmbeddedLeaderService.java
+++
b/flink-runtime/src/main/java/org/apache/flink/runtime/highavailability/nonha/embedded/EmbeddedLeaderService.java
@@ -102,6 +102,13 @@ public class EmbeddedLeaderService {
}
}
+ @VisibleForTesting
+ public boolean isShutdown() {
+ synchronized (lock) {
+ return shutdown;
+ }
+ }
+
private void fatalError(Throwable error) {
LOG.error("Embedded leader election service encountered a fatal
error. Shutting down service.", error);
@@ -171,7 +178,11 @@ public class EmbeddedLeaderService {
service.contender = contender;
service.running = true;
- updateLeader();
+ updateLeader().whenComplete((aVoid, throwable)
-> {
+ if (throwable != null) {
+ fatalError(throwable);
+ }
+ });
}
catch (Throwable t) {
fatalError(t);
@@ -210,7 +221,11 @@ public class EmbeddedLeaderService {
currentLeaderSessionId = null;
}
- updateLeader();
+ updateLeader().whenComplete((aVoid, throwable)
-> {
+ if (throwable != null) {
+ fatalError(throwable);
+ }
+ });
}
catch (Throwable t) {
fatalError(t);
@@ -280,11 +295,12 @@ public class EmbeddedLeaderService {
currentLeaderSessionId = leaderSessionId;
currentLeaderProposed = leaderService;
+ currentLeaderProposed.isLeader = true;
LOG.info("Proposing leadership to contender {}
@ {}",
leaderService.contender,
leaderService.contender.getAddress());
- return execute(new
GrantLeadershipCall(leaderService, leaderSessionId, LOG));
+ return execute(new
GrantLeadershipCall(leaderService.contender, leaderSessionId, LOG));
}
} else {
return CompletableFuture.completedFuture(null);
@@ -373,7 +389,8 @@ public class EmbeddedLeaderService {
}
LOG.info("Revoking leadership of {}.",
leaderService.contender);
- CompletableFuture<Void>
revokeLeadershipCallFuture = execute(new RevokeLeadershipCall(leaderService));
+ leaderService.isLeader = false;
+ CompletableFuture<Void>
revokeLeadershipCallFuture = execute(new
RevokeLeadershipCall(leaderService.contender));
CompletableFuture<Void>
notifyAllListenersFuture = notifyAllListeners(null, null);
@@ -506,33 +523,28 @@ public class EmbeddedLeaderService {
private static class GrantLeadershipCall implements Runnable {
- private final EmbeddedLeaderElectionService
leaderElectionService;
+ private final LeaderContender contender;
private final UUID leaderSessionId;
private final Logger logger;
GrantLeadershipCall(
- EmbeddedLeaderElectionService
leaderElectionService,
+ LeaderContender contender,
UUID leaderSessionId,
Logger logger) {
- this.leaderElectionService =
checkNotNull(leaderElectionService);
+ this.contender = checkNotNull(contender);
this.leaderSessionId = checkNotNull(leaderSessionId);
this.logger = checkNotNull(logger);
}
@Override
public void run() {
- leaderElectionService.isLeader = true;
-
- final LeaderContender contender =
leaderElectionService.contender;
-
try {
contender.grantLeadership(leaderSessionId);
}
catch (Throwable t) {
logger.warn("Error granting leadership to
contender", t);
contender.handleError(t instanceof Exception ?
(Exception) t : new Exception(t));
- leaderElectionService.isLeader = false;
}
}
}
@@ -540,17 +552,15 @@ public class EmbeddedLeaderService {
private static class RevokeLeadershipCall implements Runnable {
@Nonnull
- private final EmbeddedLeaderElectionService
leaderElectionService;
+ private final LeaderContender contender;
- RevokeLeadershipCall(@Nonnull EmbeddedLeaderElectionService
leaderElectionService) {
- this.leaderElectionService = leaderElectionService;
+ RevokeLeadershipCall(@Nonnull LeaderContender contender) {
+ this.contender = contender;
}
@Override
public void run() {
- leaderElectionService.isLeader = false;
-
- leaderElectionService.contender.revokeLeadership();
+ contender.revokeLeadership();
}
}
}
diff --git
a/flink-runtime/src/test/java/org/apache/flink/runtime/highavailability/nonha/embedded/EmbeddedHaServicesTest.java
b/flink-runtime/src/test/java/org/apache/flink/runtime/highavailability/nonha/embedded/EmbeddedHaServicesTest.java
index 2455bf0..7f06d60 100644
---
a/flink-runtime/src/test/java/org/apache/flink/runtime/highavailability/nonha/embedded/EmbeddedHaServicesTest.java
+++
b/flink-runtime/src/test/java/org/apache/flink/runtime/highavailability/nonha/embedded/EmbeddedHaServicesTest.java
@@ -24,7 +24,6 @@ import
org.apache.flink.runtime.leaderelection.LeaderContender;
import org.apache.flink.runtime.leaderelection.LeaderElectionService;
import org.apache.flink.runtime.leaderretrieval.LeaderRetrievalListener;
import org.apache.flink.runtime.leaderretrieval.LeaderRetrievalService;
-import org.apache.flink.util.ExceptionUtils;
import org.apache.flink.util.TestLogger;
import org.junit.After;
@@ -33,9 +32,6 @@ import org.junit.Test;
import org.mockito.ArgumentCaptor;
import java.util.UUID;
-import java.util.concurrent.ArrayBlockingQueue;
-import java.util.concurrent.BlockingQueue;
-import java.util.concurrent.atomic.AtomicReference;
import static junit.framework.TestCase.assertTrue;
import static org.hamcrest.Matchers.is;
@@ -179,12 +175,11 @@ public class EmbeddedHaServicesTest extends TestLogger {
@Test
public void testConcurrentLeadershipOperations() throws Exception {
final LeaderElectionService dispatcherLeaderElectionService =
embeddedHaServices.getDispatcherLeaderElectionService();
- final ArrayBlockingQueue<UUID> offeredSessionIds = new
ArrayBlockingQueue<>(2);
- final TestingLeaderContender leaderContender = new
TestingLeaderContender(offeredSessionIds);
+ final TestingLeaderContender leaderContender = new
TestingLeaderContender();
dispatcherLeaderElectionService.start(leaderContender);
- final UUID oldLeaderSessionId = offeredSessionIds.take();
+ final UUID oldLeaderSessionId =
leaderContender.getLeaderSessionFuture().get();
assertThat(dispatcherLeaderElectionService.hasLeadership(oldLeaderSessionId),
is(true));
@@ -192,7 +187,7 @@ public class EmbeddedHaServicesTest extends TestLogger {
assertThat(dispatcherLeaderElectionService.hasLeadership(oldLeaderSessionId),
is(false));
embeddedHaServices.getDispatcherLeaderService().grantLeadership();
- final UUID newLeaderSessionId = offeredSessionIds.take();
+ final UUID newLeaderSessionId =
leaderContender.getLeaderSessionFuture().get();
assertThat(dispatcherLeaderElectionService.hasLeadership(newLeaderSessionId),
is(true));
@@ -204,37 +199,4 @@ public class EmbeddedHaServicesTest extends TestLogger {
leaderContender.tryRethrowException();
}
- private static final class TestingLeaderContender implements
LeaderContender {
-
- private final BlockingQueue<UUID> offeredSessionIds;
-
- private final AtomicReference<Exception> occurredException;
-
- private TestingLeaderContender(BlockingQueue<UUID>
offeredSessionIds) {
- this.offeredSessionIds = offeredSessionIds;
- occurredException = new AtomicReference<>(null);
- }
-
- @Override
- public void grantLeadership(UUID leaderSessionID) {
- offeredSessionIds.offer(leaderSessionID);
- }
-
- @Override
- public void revokeLeadership() {}
-
- @Override
- public String getAddress() {
- return "foobar";
- }
-
- @Override
- public void handleError(Exception exception) {
- occurredException.compareAndSet(null, exception);
- }
-
- public void tryRethrowException() throws Exception {
-
ExceptionUtils.tryRethrowException(occurredException.get());
- }
- }
}
diff --git
a/flink-runtime/src/test/java/org/apache/flink/runtime/highavailability/nonha/embedded/EmbeddedLeaderServiceTest.java
b/flink-runtime/src/test/java/org/apache/flink/runtime/highavailability/nonha/embedded/EmbeddedLeaderServiceTest.java
new file mode 100644
index 0000000..6ecc967
--- /dev/null
+++
b/flink-runtime/src/test/java/org/apache/flink/runtime/highavailability/nonha/embedded/EmbeddedLeaderServiceTest.java
@@ -0,0 +1,103 @@
+/*
+ * 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.flink.runtime.highavailability.nonha.embedded;
+
+import org.apache.flink.runtime.leaderelection.LeaderElectionService;
+import org.apache.flink.runtime.testingUtils.TestingUtils;
+import org.apache.flink.util.TestLogger;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+
+import static org.hamcrest.Matchers.is;
+
+/**
+ * Tests for the {@link EmbeddedLeaderService}.
+ */
+public class EmbeddedLeaderServiceTest extends TestLogger {
+
+ /**
+ * Tests that the {@link EmbeddedLeaderService} can handle a concurrent
grant
+ * leadership call and a shutdown.
+ */
+ @Test
+ public void testConcurrentGrantLeadershipAndShutdown() throws Exception
{
+ final EmbeddedLeaderService embeddedLeaderService = new
EmbeddedLeaderService(TestingUtils.defaultExecutor());
+
+ try {
+ final LeaderElectionService leaderElectionService =
embeddedLeaderService.createLeaderElectionService();
+
+ final TestingLeaderContender contender = new
TestingLeaderContender();
+
+ leaderElectionService.start(contender);
+ leaderElectionService.stop();
+
+ try {
+ // check that no exception occurred
+ contender.getLeaderSessionFuture().get(10L,
TimeUnit.MILLISECONDS);
+ } catch (TimeoutException ignored) {
+ // we haven't participated in the leader
election
+ }
+
+ // the election service should still be running
+ Assert.assertThat(embeddedLeaderService.isShutdown(),
is(false));
+ } finally {
+ embeddedLeaderService.shutdown();
+ }
+ }
+
+ /**
+ * Tests that the {@link EmbeddedLeaderService} can handle a concurrent
revoke
+ * leadership call and a shutdown.
+ */
+ @Test
+ public void testConcurrentRevokeLeadershipAndShutdown() throws
Exception {
+ final EmbeddedLeaderService embeddedLeaderService = new
EmbeddedLeaderService(TestingUtils.defaultExecutor());
+
+ try {
+ final LeaderElectionService leaderElectionService =
embeddedLeaderService.createLeaderElectionService();
+
+ final TestingLeaderContender contender = new
TestingLeaderContender();
+
+ leaderElectionService.start(contender);
+
+ // wait for the leadership
+ contender.getLeaderSessionFuture().get();
+
+ final CompletableFuture<Void> revokeLeadershipFuture =
embeddedLeaderService.revokeLeadership();
+ leaderElectionService.stop();
+
+ try {
+ // check that no exception occurred
+ revokeLeadershipFuture.get(10L,
TimeUnit.MILLISECONDS);
+ } catch (TimeoutException ignored) {
+ // the leader election service has been stopped
before revoking could be executed
+ }
+
+ // the election service should still be running
+ Assert.assertThat(embeddedLeaderService.isShutdown(),
is(false));
+ } finally {
+ embeddedLeaderService.shutdown();
+ }
+ }
+}
diff --git
a/flink-runtime/src/test/java/org/apache/flink/runtime/highavailability/nonha/embedded/TestingLeaderContender.java
b/flink-runtime/src/test/java/org/apache/flink/runtime/highavailability/nonha/embedded/TestingLeaderContender.java
new file mode 100644
index 0000000..0b28671
--- /dev/null
+++
b/flink-runtime/src/test/java/org/apache/flink/runtime/highavailability/nonha/embedded/TestingLeaderContender.java
@@ -0,0 +1,87 @@
+/*
+ * 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.flink.runtime.highavailability.nonha.embedded;
+
+import org.apache.flink.runtime.concurrent.FutureUtils;
+import org.apache.flink.runtime.leaderelection.LeaderContender;
+
+import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
+
+/**
+ * {@link LeaderContender} implementation for testing purposes.
+ */
+final class TestingLeaderContender implements LeaderContender {
+
+ private final Object lock = new Object();
+
+ private CompletableFuture<UUID> leaderSessionFuture;
+
+ TestingLeaderContender() {
+ leaderSessionFuture = new CompletableFuture<>();
+ }
+
+ @Override
+ public void grantLeadership(UUID leaderSessionID) {
+ synchronized (lock) {
+ if (!leaderSessionFuture.isCompletedExceptionally()) {
+ if
(!leaderSessionFuture.complete(leaderSessionID)) {
+ leaderSessionFuture =
CompletableFuture.completedFuture(leaderSessionID);
+ }
+ }
+ }
+ }
+
+ @Override
+ public void revokeLeadership() {
+ synchronized (lock) {
+ if (leaderSessionFuture.isDone() &&
!leaderSessionFuture.isCompletedExceptionally()) {
+ leaderSessionFuture = new CompletableFuture<>();
+ }
+ }
+ }
+
+ @Override
+ public String getAddress() {
+ return "foobar";
+ }
+
+ @Override
+ public void handleError(Exception exception) {
+ synchronized (lock) {
+ if (!(leaderSessionFuture.isCompletedExceptionally() ||
leaderSessionFuture.completeExceptionally(exception))) {
+ leaderSessionFuture =
FutureUtils.completedExceptionally(exception);
+ }
+ }
+ }
+
+ public void tryRethrowException() {
+ synchronized (lock) {
+ if (leaderSessionFuture.isCompletedExceptionally()) {
+ leaderSessionFuture.getNow(null);
+ }
+ }
+ }
+
+ CompletableFuture<UUID> getLeaderSessionFuture() {
+ synchronized (lock) {
+ return leaderSessionFuture;
+ }
+ }
+}
