package rpc.impl;
import java.io.IOException;
import java.util.List;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher.Event.EventType;
import org.apache.zookeeper.Watcher.Event.KeeperState;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooKeeper;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import rpc.NotifyListener;
import rpc.Registry;
import rpc.URL;
import rpc.model.ConsumerConstants;
import rpc.model.ProviderConstants;
/**
* ZK节点格式：
* ZK
* |
* appKey1 appKey2...
* |
* service1 service2...
* |
* consumers providers
* | |
* ip1 ip2... ip1 ip2...
*
* @author bird
*
*/
public class ZookeeperRegistry implements Registry{
/**
* zk连接超时时间
*/
private static final int ZK_CONNECT_TIMEOUT = 1000;
/**
* zookeeper客户端
*/
private ZooKeeper zk;
/**
* zk注册中心全局锁
*/
private final Lock mutex = new ReentrantLock();
/**
* 连接状态锁
*/
private final Condition connCondition = mutex.newCondition();
/**
* 注册中心url
*/
private final URL registryUrl;
/**
* 标识zookeeper连接中心是否可用
*/
private volatile boolean isAvailable;
public ZookeeperRegistry(URL registryUrl) throws IOException {
Preconditions.checkNotNull(registryUrl);
this.registryUrl = registryUrl;
// 初始化zk注册中心
init();
}
/**
* 初始化注册中心
* @throws IOException zookeeper连接异常
*/
private void init() throws IOException {
// 获取zookeeper连接IP
String connectString = registryUrl.connectString();
Preconditions.checkNotNull(connectString);
mutex.lock();
try {
// 新建zookeeper连接
zk = new ZooKeeper(connectString, ZK_CONNECT_TIMEOUT, new ConnectionWatcher());
// 等待连接完成,超时时间设置为2倍zk连接超时时间
connCondition.await(ZK_CONNECT_TIMEOUT << 1, TimeUnit.MILLISECONDS);
// 设置初始状态
this.isAvailable = true;
} catch (InterruptedException e) {
e.printStackTrace();
}finally {
mutex.unlock();
}
}
private class ConnectionWatcher implements Watcher{
/*
* 当连接成功时，供回调
*/
@Override
public void process(WatchedEvent event) {
// 传来NONE类型事件，一般是连接事件等
if(event.getType() == EventType.None) {
// 事件状态为：连接中
if(event.getState() == KeeperState.SyncConnected) {
// 唤醒等待连接成功的线程
mutex.lock();
try {
// 唤醒等待连接成功的线程
connCondition.signalAll();
} finally {
mutex.unlock();
}
}
}
}
}
private class ChildrenWatcher implements Watcher{
/**
* 监视器所监视的zk路径
*/
private String path;
/**
* url列表的监听器
*/
private NotifyListener listener;
public ChildrenWatcher(String path, NotifyListener listener){
this.path = path;
this.listener = listener;
}
@Override
public void process(WatchedEvent event) {
// 如果和zk服务器保持连接中
if(event.getState() == KeeperState.SyncConnected) {
switch(event.getType()) {
// providers子节点发生改变，更新服务列表
case NodeChildrenChanged:{
try {
// 获取发生变动的列表，重置监听器
List<String> paths = zk.getChildren(path, this);
// 通知listener
doNotify(listener, paths);
} catch (KeeperException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
default :{
//TODO
}
}
}
}
}
@Override
public URL getUrl() {
return registryUrl;
}
@Override
public boolean isAvailable() {
return isAvailable;
}
@Override
public void destroy() {
// TODO Auto-generated method stub
}
@Override
public void register(URL url) throws Exception {
Preconditions.checkNotNull(url);
Preconditions.checkNotNull(url.getPath());
// 获取url对应的zk路径
String providerPath = getProviderPath(url);
// 在zk服务器上建立相应路径
zk.create(providerPath, "".getBytes(), null, CreateMode.EPHEMERAL);
}
@Override
public void unregister(URL url) throws Exception {
Preconditions.checkNotNull(url);
Preconditions.checkNotNull(url.getPath());
// 获取url对应的zk路径
String providerPath = getProviderPath(url);
// 在zk服务器上删除相应路径
zk.delete(providerPath, -1);
}
/**
* zookeeper操作：
* 1. getChildren /appKey/service/providers/, watcher 获取IP节点列表
* 2. create /appKey/service/consumers/IP 注册信息到IP节点
*
* watcher监视IP节点列表的变化
* @param url service url
* @param listener
* @throws Exception
*/
@Override
public void subscribe(URL url, NotifyListener listener) throws Exception {
Preconditions.checkNotNull(url);
Preconditions.checkNotNull(url.getPath());
Preconditions.checkNotNull(listener);
// 生成provider路径
String providerPath = getProviderPath(url);
// 获取IP节点列表
// 新建watcher监听节点目录变化
Watcher watcher = new ChildrenWatcher(providerPath, listener);
// 获取IP节点列表
List<String> paths = zk.getChildren(providerPath, watcher);
// 通知listener
doNotify(listener, paths);
// 注册信息到IP节点
// 生成consumer路径
String consumerPath = getConsumerPath(url);
// 创建consumer节点
zk.create(consumerPath, "".getBytes(), null, CreateMode.EPHEMERAL);
}
/**
* 实际执行listener回调
* @param listener
* @param paths 获取的zk路径信息
*/
private void doNotify(NotifyListener listener, List<String> paths) {
// 新建不可变url列表的builder
ImmutableList.Builder<URL> listBuilder = ImmutableList.builder();
// 将所有获取的path全部转化成url并放入列表
paths.forEach(p -> {
URL u = URL.builder().str(p).build();
listBuilder.add(u);
});
// 新建url缓存
List<URL> urls = listBuilder.build();
// 回调监听器
listener.notify(urls);
}
/**
* zookeeper操作:
* 1. delete /appkey/service/consumer/IP
* @param url service url
* @param listener
* @throws Exception
*/
@Override
public void unsubscribe(URL url, NotifyListener listener) throws Exception {
Preconditions.checkNotNull(url);
Preconditions.checkNotNull(url.getPath());
Preconditions.checkNotNull(listener);
// 生成consumer路径
String consumerPath = getConsumerPath(url);
// TODO 版本问题 删除zk上的路径
zk.delete(consumerPath, -1);
// 传入空列表，回调监听器
listener.notify(ImmutableList.of());
}
/**
* zookeeper操作：
* 1. getChildren /appKey/service/providers/
* @param url
* @return
* @throws Exception
*/
@Override
public List<URL> lookup(URL url) throws Exception {
Preconditions.checkNotNull(url);
Preconditions.checkNotNull(url.getPath());
// 生成provider路径
String providerPath = getProviderPath(url);
// 获取IP节点列表
List<String> paths = zk.getChildren(providerPath, false);
// 新建不可变url列表的builder
ImmutableList.Builder<URL> listBuilder = ImmutableList.builder();
// 将所有获取的path全部转化成url并放入列表
paths.forEach(p -> {
URL u = URL.builder().str(p).build();
listBuilder.add(u);
});
// 新建url缓存
List<URL> urls = listBuilder.build();
return urls;
}
/**
* 形如: /appKey/service/providers/IP
* @param url
* @return
*/
private String getProviderPath(URL url) {
Preconditions.checkNotNull(url);
// 获取path
String path = url.getPath();
// path必须存在且以providers结尾
Preconditions.checkNotNull(path);
Preconditions.checkArgument(path.endsWith(ProviderConstants.PROVIDERS));;
// 正确格式 /appKey/service/providers/ 至少有三个分隔
StringBuilder builder = new StringBuilder(path);
// 组装/appKey/service/providers/IP格式
builder.append(URL.PATH_SPLIT)
.append(url.connectString());
return builder.toString();
}
/**
* 形如: /appKey/service/consumers/IP
* @param url
* @return
*/
private String getConsumerPath(URL url) {
Preconditions.checkNotNull(url);
// 获取path
String path = url.getPath();
// path必须存在且以consumes结尾
Preconditions.checkNotNull(path);
Preconditions.checkArgument(path.endsWith(ConsumerConstants.CONSUMERS));;
// 正确格式 /appKey/service/consumers/ 至少有三个分隔
StringBuilder builder = new StringBuilder(path);
// 组装/appKey/service/consumers/IP格式
builder.append(URL.PATH_SPLIT)
.append(url.connectString());
return builder.toString();
}
}
