/*
* Copyright (C) 2010-2101 Alibaba Group Holding Limited.
*
* 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.alibaba.otter.shared.common.utils.zookeeper;
import java.io.IOException;
import java.lang.reflect.Field;
import java.net.InetSocketAddress;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import org.I0Itec.zkclient.IZkConnection;
import org.I0Itec.zkclient.exception.ZkException;
import org.apache.commons.lang.StringUtils;
import org.apache.zookeeper.ClientCnxn;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.ZooDefs.Ids;
import org.apache.zookeeper.ZooKeeper.States;
import org.apache.zookeeper.client.ConnectStringParser;
import org.apache.zookeeper.client.HostProvider;
import org.apache.zookeeper.client.StaticHostProvider;
import org.apache.zookeeper.data.Stat;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.ReflectionUtils;
/**
* 封装了ZooKeeper，使其支持节点的优先顺序，比如美国机房的节点会优先加载美国对应的zk集群列表，都失败后才会选择加载杭州的zk集群列表 *
*
* @author jianghang 2012-7-10 下午02:31:42
* @version 4.1.0
*/
public class ZooKeeperx implements IZkConnection {
private static final String SERVER_COMMA = ";";
private static final Logger logger = LoggerFactory.getLogger(ZooKeeperx.class);
private static final Field clientCnxnField = ReflectionUtils.findField(ZooKeeper.class, "cnxn");
private static final Field hostProviderField = ReflectionUtils.findField(ClientCnxn.class, "hostProvider");
private static final Field serverAddressesField = ReflectionUtils.findField(StaticHostProvider.class,
"serverAddresses");
private static final int DEFAULT_SESSION_TIMEOUT = 90000;
private ZooKeeper _zk = null;
private Lock _zookeeperLock = new ReentrantLock();
private final List<String> _servers;
private final int _sessionTimeOut;
public ZooKeeperx(String zkServers){
this(zkServers, DEFAULT_SESSION_TIMEOUT);
}
public ZooKeeperx(String zkServers, int sessionTimeOut){
_servers = Arrays.asList(StringUtils.split(zkServers, SERVER_COMMA));
_sessionTimeOut = sessionTimeOut;
}
@Override
public void connect(Watcher watcher) {
_zookeeperLock.lock();
try {
if (_zk != null) {
throw new IllegalStateException("zk client has already been started");
}
try {
logger.debug("Creating new ZookKeeper instance to connect to " + _servers + ".");
_zk = new ZooKeeper(_servers.get(0), _sessionTimeOut, watcher);
configMutliCluster(_zk);
} catch (IOException e) {
throw new ZkException("Unable to connect to " + _servers, e);
}
} finally {
_zookeeperLock.unlock();
}
}
public void close() throws InterruptedException {
_zookeeperLock.lock();
try {
if (_zk != null) {
logger.debug("Closing ZooKeeper connected to " + _servers);
_zk.close();
_zk = null;
}
} finally {
_zookeeperLock.unlock();
}
}
public String create(String path, byte[] data, CreateMode mode) throws KeeperException, InterruptedException {
return _zk.create(path, data, Ids.OPEN_ACL_UNSAFE, mode);
}
public void delete(String path) throws InterruptedException, KeeperException {
_zk.delete(path, -1);
}
public boolean exists(String path, boolean watch) throws KeeperException, InterruptedException {
return _zk.exists(path, watch) != null;
}
public List<String> getChildren(final String path, final boolean watch) throws KeeperException,
InterruptedException {
return _zk.getChildren(path, watch);
}
public byte[] readData(String path, Stat stat, boolean watch) throws KeeperException, InterruptedException {
return _zk.getData(path, watch, stat);
}
public void writeData(String path, byte[] data) throws KeeperException, InterruptedException {
writeData(path, data, -1);
}
public void writeData(String path, byte[] data, int version) throws KeeperException, InterruptedException {
_zk.setData(path, data, version);
}
public States getZookeeperState() {
return _zk != null ? _zk.getState() : null;
}
public ZooKeeper getZookeeper() {
return _zk;
}
public long getCreateTime(String path) throws KeeperException, InterruptedException {
Stat stat = _zk.exists(path, false);
if (stat != null) {
return stat.getCtime();
}
return -1;
}
public String getServers() {
return StringUtils.join(_servers, SERVER_COMMA);
}
// ===============================
public void configMutliCluster(ZooKeeper zk) {
if (_servers.size() == 1) {
return;
}
String cluster1 = _servers.get(0);
try {
if (_servers.size() > 1) {
// 强制的声明accessible
ReflectionUtils.makeAccessible(clientCnxnField);
ReflectionUtils.makeAccessible(hostProviderField);
ReflectionUtils.makeAccessible(serverAddressesField);
// 添加第二组集群列表
for (int i = 1; i < _servers.size(); i++) {
String cluster = _servers.get(i);
// 强制获取zk中的地址信息
ClientCnxn cnxn = (ClientCnxn) ReflectionUtils.getField(clientCnxnField, zk);
HostProvider hostProvider = (HostProvider) ReflectionUtils.getField(hostProviderField, cnxn);
List<InetSocketAddress> serverAddrs = (List<InetSocketAddress>) ReflectionUtils.getField(serverAddressesField,
hostProvider);
// 添加第二组集群列表
serverAddrs.addAll(new ConnectStringParser(cluster).getServerAddresses());
}
}
} catch (Exception e) {
try {
if (zk != null) {
zk.close();
}
} catch (InterruptedException ie) {
// ignore interrupt
}
throw new ZkException("zookeeper_create_error, serveraddrs=" + cluster1, e);
}
}
}