/**
* 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.zookeeper.retry;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.ACL;
import org.apache.zookeeper.data.Stat;
import org.apache.zookeeper.inspector.logger.LoggerFactory;
/**
* A Class which extends {@link ZooKeeper} and will automatically retry calls to
* zookeeper if a {@link KeeperException.ConnectionLossException} occurs
*/
public class ZooKeeperRetry extends ZooKeeper {
private boolean closed = false;
private final Watcher watcher;
private int limit = -1;
/**
* @param connectString
* @param sessionTimeout
* @param watcher
* @throws IOException
*/
public ZooKeeperRetry(String connectString, int sessionTimeout,
Watcher watcher) throws IOException {
super(connectString, sessionTimeout, watcher);
this.watcher = watcher;
}
/**
* @param connectString
* @param sessionTimeout
* @param watcher
* @param sessionId
* @param sessionPasswd
* @throws IOException
*/
public ZooKeeperRetry(String connectString, int sessionTimeout,
Watcher watcher, long sessionId, byte[] sessionPasswd)
throws IOException {
super(connectString, sessionTimeout, watcher, sessionId, sessionPasswd);
this.watcher = watcher;
}
@Override
public synchronized void close() throws InterruptedException {
this.closed = true;
super.close();
}
@Override
public String create(String path, byte[] data, List<ACL> acl,
CreateMode createMode) throws KeeperException, InterruptedException {
int count = 0;
do {
try {
return super.create(path, data, acl, createMode);
} catch (KeeperException.ConnectionLossException e) {
LoggerFactory.getLogger().warn(
"ZooKeeper connection lost. Trying to reconnect.");
if (exists(path, false) != null) {
return path;
}
} catch (KeeperException.NodeExistsException e) {
return path;
}
} while (!closed && (limit == -1 || count++ < limit));
return null;
}
@Override
public void delete(String path, int version) throws InterruptedException,
KeeperException {
int count = 0;
do {
try {
super.delete(path, version);
} catch (KeeperException.ConnectionLossException e) {
LoggerFactory.getLogger().warn(
"ZooKeeper connection lost. Trying to reconnect.");
if (exists(path, false) == null) {
return;
}
} catch (KeeperException.NoNodeException e) {
break;
}
} while (!closed && (limit == -1 || count++ < limit));
}
@Override
public Stat exists(String path, boolean watch) throws KeeperException,
InterruptedException {
int count = 0;
do {
try {
return super.exists(path, watch ? watcher : null);
} catch (KeeperException.ConnectionLossException e) {
LoggerFactory.getLogger().warn(
"ZooKeeper connection lost. Trying to reconnect.");
}
} while (!closed && (limit == -1 || count++ < limit));
return null;
}
@Override
public Stat exists(String path, Watcher watcher) throws KeeperException,
InterruptedException {
int count = 0;
do {
try {
return super.exists(path, watcher);
} catch (KeeperException.ConnectionLossException e) {
LoggerFactory.getLogger().warn(
"ZooKeeper connection lost. Trying to reconnect.");
}
} while (!closed && (limit == -1 || count++ < limit));
return null;
}
@Override
public List<ACL> getACL(String path, Stat stat) throws KeeperException,
InterruptedException {
int count = 0;
do {
try {
return super.getACL(path, stat);
} catch (KeeperException.ConnectionLossException e) {
LoggerFactory.getLogger().warn(
"ZooKeeper connection lost. Trying to reconnect.");
}
} while (!closed && (limit == -1 || count++ < limit));
return null;
}
@Override
public List<String> getChildren(String path, boolean watch)
throws KeeperException, InterruptedException {
int count = 0;
do {
try {
return super.getChildren(path, watch ? watcher : null);
} catch (KeeperException.ConnectionLossException e) {
LoggerFactory.getLogger().warn(
"ZooKeeper connection lost. Trying to reconnect.");
}
} while (!closed && (limit == -1 || count++ < limit));
return new ArrayList<String>();
}
@Override
public List<String> getChildren(String path, Watcher watcher)
throws KeeperException, InterruptedException {
int count = 0;
do {
try {
return super.getChildren(path, watcher);
} catch (KeeperException.ConnectionLossException e) {
LoggerFactory.getLogger().warn(
"ZooKeeper connection lost. Trying to reconnect.");
}
} while (!closed && (limit == -1 || count++ < limit));
return new ArrayList<String>();
}
@Override
public byte[] getData(String path, boolean watch, Stat stat)
throws KeeperException, InterruptedException {
int count = 0;
do {
try {
return super.getData(path, watch ? watcher : null, stat);
} catch (KeeperException.ConnectionLossException e) {
LoggerFactory.getLogger().warn(
"ZooKeeper connection lost. Trying to reconnect.");
}
} while (!closed && (limit == -1 || count++ < limit));
return null;
}
@Override
public byte[] getData(String path, Watcher watcher, Stat stat)
throws KeeperException, InterruptedException {
int count = 0;
do {
try {
return super.getData(path, watcher, stat);
} catch (KeeperException.ConnectionLossException e) {
LoggerFactory.getLogger().warn(
"ZooKeeper connection lost. Trying to reconnect.");
}
} while (!closed && (limit == -1 || count++ < limit));
return null;
}
@Override
public Stat setACL(String path, List<ACL> acl, int version)
throws KeeperException, InterruptedException {
int count = 0;
do {
try {
return super.setACL(path, acl, version);
} catch (KeeperException.ConnectionLossException e) {
LoggerFactory.getLogger().warn(
"ZooKeeper connection lost. Trying to reconnect.");
Stat s = exists(path, false);
if (s != null) {
if (getACL(path, s).equals(acl)) {
return s;
}
} else {
return null;
}
}
} while (!closed && (limit == -1 || count++ < limit));
return null;
}
@Override
public Stat setData(String path, byte[] data, int version)
throws KeeperException, InterruptedException {
int count = 0;
do {
try {
return super.setData(path, data, version);
} catch (KeeperException.ConnectionLossException e) {
LoggerFactory.getLogger().warn(
"ZooKeeper connection lost. Trying to reconnect.");
Stat s = exists(path, false);
if (s != null) {
if (getData(path, false, s) == data) {
return s;
}
} else {
return null;
}
}
} while (!closed && (limit == -1 || count++ < limit));
return null;
}
/**
* @param limit
*/
public void setRetryLimit(int limit) {
this.limit = limit;
}
/**
* @return true if successfully connected to zookeeper
*/
public boolean testConnection() {
int count = 0;
do {
try {
return super.exists("/", null) != null;
} catch (Exception e) {
LoggerFactory.getLogger().warn(
"ZooKeeper connection lost. Trying to reconnect.");
}
} while (count++ < 5);
return false;
}
}