org.apache.flink.runtime.checkpoint.ZooKeeperCheckpointIDCounter Maven / Gradle / Ivy
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* 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.checkpoint;
import org.apache.flink.annotation.VisibleForTesting;
import org.apache.flink.api.common.JobStatus;
import org.apache.flink.runtime.jobmanager.HighAvailabilityMode;
import org.apache.flink.runtime.util.ZooKeeperUtils;
import org.apache.flink.util.FlinkException;
import org.apache.flink.util.Preconditions;
import org.apache.flink.util.concurrent.FutureUtils;
import org.apache.flink.shaded.curator5.com.google.common.collect.Sets;
import org.apache.flink.shaded.curator5.org.apache.curator.framework.CuratorFramework;
import org.apache.flink.shaded.curator5.org.apache.curator.framework.api.CuratorEvent;
import org.apache.flink.shaded.curator5.org.apache.curator.framework.api.CuratorEventType;
import org.apache.flink.shaded.curator5.org.apache.curator.framework.recipes.shared.SharedCount;
import org.apache.flink.shaded.curator5.org.apache.curator.framework.recipes.shared.VersionedValue;
import org.apache.flink.shaded.curator5.org.apache.curator.framework.state.ConnectionState;
import org.apache.flink.shaded.zookeeper3.org.apache.zookeeper.KeeperException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.annotation.concurrent.GuardedBy;
import java.io.IOException;
import java.util.Optional;
import java.util.concurrent.CompletableFuture;
import static org.apache.flink.util.Preconditions.checkNotNull;
/**
* {@link CheckpointIDCounter} instances for JobManagers running in {@link
* HighAvailabilityMode#ZOOKEEPER}.
*
* Each counter creates a ZNode:
*
*
* +----O /flink/checkpoint-counter/<job-id> 1 [persistent]
* .
* .
* .
* +----O /flink/checkpoint-counter/<job-id> N [persistent]
*
*
* The checkpoints IDs are required to be ascending (per job). In order to guarantee this in case
* of job manager failures we use ZooKeeper to have a shared counter across job manager instances.
*/
public class ZooKeeperCheckpointIDCounter implements CheckpointIDCounter {
private static final Logger LOG = LoggerFactory.getLogger(ZooKeeperCheckpointIDCounter.class);
/** Curator ZooKeeper client. */
private final CuratorFramework client;
/** Path of the shared count. */
private final String counterPath;
/** Curator recipe for shared counts. */
private final SharedCount sharedCount;
private final LastStateConnectionStateListener connectionStateListener;
private final Object startStopLock = new Object();
@GuardedBy("startStopLock")
private boolean isStarted;
/**
* Creates a {@link ZooKeeperCheckpointIDCounter} instance.
*
* @param client Curator ZooKeeper client
*/
public ZooKeeperCheckpointIDCounter(
CuratorFramework client, LastStateConnectionStateListener connectionStateListener) {
this.client = checkNotNull(client, "Curator client");
this.counterPath = ZooKeeperUtils.getCheckpointIdCounterPath();
this.sharedCount = new SharedCount(client, counterPath, INITIAL_CHECKPOINT_ID);
this.connectionStateListener = connectionStateListener;
}
@Override
public void start() throws Exception {
synchronized (startStopLock) {
if (!isStarted) {
sharedCount.start();
client.getConnectionStateListenable().addListener(connectionStateListener);
isStarted = true;
}
}
}
@Override
public CompletableFuture shutdown(JobStatus jobStatus) {
synchronized (startStopLock) {
if (isStarted) {
LOG.info("Shutting down.");
try {
sharedCount.close();
} catch (IOException e) {
return FutureUtils.completedExceptionally(e);
}
client.getConnectionStateListenable().removeListener(connectionStateListener);
if (jobStatus.isGloballyTerminalState()) {
LOG.info("Removing {} from ZooKeeper", counterPath);
try {
final CompletableFuture deletionFuture = new CompletableFuture<>();
client.delete()
.inBackground(
(curatorFramework, curatorEvent) ->
handleDeletionOfCounterPath(
curatorEvent, deletionFuture))
.forPath(counterPath);
return deletionFuture;
} catch (Exception e) {
return FutureUtils.completedExceptionally(e);
}
}
isStarted = false;
}
}
return FutureUtils.completedVoidFuture();
}
private void handleDeletionOfCounterPath(
CuratorEvent curatorEvent, CompletableFuture deletionFuture) {
Preconditions.checkArgument(
curatorEvent.getType() == CuratorEventType.DELETE,
"An unexpected CuratorEvent was monitored: " + curatorEvent.getType());
Preconditions.checkArgument(
counterPath.endsWith(curatorEvent.getPath()),
"An unexpected path was selected for deletion: " + curatorEvent.getPath());
final KeeperException.Code eventCode =
KeeperException.Code.get(curatorEvent.getResultCode());
if (Sets.immutableEnumSet(KeeperException.Code.OK, KeeperException.Code.NONODE)
.contains(eventCode)) {
deletionFuture.complete(null);
} else {
final String namespacedCounterPath =
ZooKeeperUtils.generateZookeeperPath(client.getNamespace(), counterPath);
deletionFuture.completeExceptionally(
new FlinkException(
String.format(
"An error occurred while shutting down the CheckpointIDCounter in path '%s'.",
namespacedCounterPath),
KeeperException.create(eventCode, namespacedCounterPath)));
}
}
@Override
public long getAndIncrement() throws Exception {
while (true) {
checkConnectionState();
VersionedValue current = sharedCount.getVersionedValue();
int newCount = current.getValue() + 1;
if (newCount < 0) {
// overflow and wrap around
throw new Exception(
"Checkpoint counter overflow. ZooKeeper checkpoint counter only supports "
+ "checkpoints Ids up to "
+ Integer.MAX_VALUE);
}
if (sharedCount.trySetCount(current, newCount)) {
return current.getValue();
}
}
}
@Override
public long get() {
checkConnectionState();
return sharedCount.getVersionedValue().getValue();
}
@Override
public void setCount(long newId) throws Exception {
checkConnectionState();
if (newId > Integer.MAX_VALUE) {
throw new IllegalArgumentException(
"ZooKeeper checkpoint counter only supports "
+ "checkpoints Ids up to "
+ Integer.MAX_VALUE
+ ", but given value is"
+ newId);
}
sharedCount.setCount((int) newId);
}
private void checkConnectionState() {
final Optional optionalLastState = connectionStateListener.getLastState();
optionalLastState.ifPresent(
lastState -> {
if (lastState != ConnectionState.CONNECTED
&& lastState != ConnectionState.RECONNECTED) {
throw new IllegalStateException("Connection state: " + lastState);
}
});
}
@VisibleForTesting
String getPath() {
return counterPath;
}
}