一、Master.java
package com.dayw.zk;
import java.io.IOException;
import java.util.Random;
import org.apache.zookeeper.AsyncCallback.DataCallback;
import org.apache.zookeeper.AsyncCallback.StringCallback;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.KeeperException.Code;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooDefs;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.Stat;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class Master implements Watcher {
static final Logger LOG = LoggerFactory.getLogger(Master.class);
ZooKeeper zk;
static String hostPort;
public Master(String host) {
super();
this.hostPort = host;
}
void startZK(String host) {
try {
zk = new ZooKeeper(host, 15000, this);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
void stopZK() {
try {
zk.close();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void process(WatchedEvent e) {
System.out.println(e);
}
Random ran = new Random();
String serverId = Integer.toHexString(ran.nextInt());
static boolean isLeader = false;
StringCallback masterCreateCallback = new StringCallback() {
@Override
public void processResult(int rc, String path, Object ctx, String name) {
switch (Code.get(rc)) {
case CONNECTIONLOSS:
checkMaster();
return;
case OK:
isLeader = true;
break;
default:
isLeader = false;
break;
}
System.out.println("I'm " + (isLeader ? "" : "not ") +
"the leader");
}
};
DataCallback masterCheckCallback = new DataCallback() {
@Override
public void processResult(int rc, String path, Object ctx, byte[] data, Stat stat) {
switch (Code.get(rc)) {
case CONNECTIONLOSS:
checkMaster();
return;
case NONODE:
try {
runForMaster();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return;
default:
break;
}
}
};
void checkMaster() {
zk.getData("/master", false, masterCheckCallback, null);
/**
* 同步
* while (true) {
Stat stat = new Stat();
try {
byte data[] = zk.getData("/master", false, stat);
isLeader = new String(data).equals(serverId);
return true;
} catch (KeeperException e) {
return false;
} catch (InterruptedException e) {
}
} */
}
void runForMaster() throws InterruptedException {
/** 异步 */
zk.create("/master", serverId.getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL, masterCreateCallback, null);
/** 同步
* while (true) {
try {
zk.create("/master", serverId.getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL);
isLeader = true;
break;
} catch (NodeExistsException e) {
isLeader = false;
break;
}
catch (KeeperException e) {
}
if (checkMaster())
break;
} */
}
public void bootstrap() {
createParent("/workers", new byte[0]);
createParent("/assign", new byte[0]);
createParent("/tasks", new byte[0]);
createParent("/status", new byte[0]);
}
StringCallback createParentCallback = new StringCallback() {
@Override
public void processResult(int rc, String path, Object ctx, String name) {
switch (Code.get(rc)) {
case CONNECTIONLOSS:
createParent(path, (byte[]) ctx);
break;
case OK:
LOG.info("Parent created");
break;
case NODEEXISTS:
LOG.warn("Parent already registerd: " + path);
break;
default:
LOG.error("Something went wrong: " + KeeperException.create(Code.get(rc), path));
break;
}
}
};
void createParent(String path, byte[] data) {
zk.create(path, data, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT, createParentCallback, data);
}
public static void main(String[] args) throws Exception {
Master z = new Master("172.16.16.176,2181");
z.startZK(hostPort);
z.runForMaster();
if (isLeader) {
System.out.println("I'm the leader");
Thread.sleep(60000);
} else {
System.out.println("Someone else is the leader");
}
z.stopZK();
}
}
二、Worker.java
package com.dayw.zk;
import java.io.IOException;
import java.util.Random;
import org.apache.zookeeper.AsyncCallback.StatCallback;
import org.apache.zookeeper.AsyncCallback.StringCallback;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.KeeperException.Code;
import org.apache.zookeeper.data.Stat;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooDefs;
import org.apache.zookeeper.ZooKeeper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class Worker implements Watcher {
private static final Logger LOG = LoggerFactory.getLogger(Worker.class);
ZooKeeper zk;
String hostPort;
String status;
String serverId = Integer.toHexString(new Random().nextInt());
public Worker(String hostPort) {
this.hostPort = hostPort;
}
void startZK() throws IOException {
zk = new ZooKeeper(hostPort, 1500, this);
}
@Override
public void process(WatchedEvent event) {
LOG.info(event.toString() + ", " + hostPort);
}
StringCallback createWorkerCallback = new StringCallback() {
@Override
public void processResult(int rc, String path, Object ctx, String name) {
switch (Code.get(rc)) {
case CONNECTIONLOSS:
register();
break;
case OK:
LOG.info("Registered successfully:" + serverId);
break;
case NODEEXISTS:
LOG.warn("Already registered:" + serverId);
break;
default:
LOG.error("Something went wrong:" + KeeperException.create(Code.get(rc), path));
break;
}
}
};
void register() {
zk.create("/workers/worker-" + serverId,
"Idle".getBytes(),
ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL, createWorkerCallback, null);
}
/** setStatus */
StatCallback statusUpdateCallback = new StatCallback() {
@Override
public void processResult(int rc, String path, Object ctx, Stat stat) {
switch (Code.get(rc)) {
case CONNECTIONLOSS:
updateStatus("test" , (String)ctx);
return;
default:
break;
}
}
};
synchronized private void updateStatus(String name, String status) {
if (status == this.status) {
zk.setData("/workers" + name, status.getBytes(), -1, statusUpdateCallback, status);
}
}
public void setStatus(String status) {
this.status = status;
updateStatus("test", status);
}
public static void main(String[] args) throws Exception {
Worker w = new Worker(args[0]);
w.startZK();
w.register();
Thread.sleep(30000);
}
}
三、Client.java
package com.dayw.zk;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.KeeperException.ConnectionLossException;
import org.apache.zookeeper.KeeperException.NodeExistsException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooDefs;
import org.apache.zookeeper.ZooKeeper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class Client implements Watcher {
private static final Logger LOG = LoggerFactory.getLogger(Client.class);
ZooKeeper zk;
String hostPort;
Client(String hostPort) {
this.hostPort = hostPort;
}
void startZK() throws Exception {
zk = new ZooKeeper(hostPort, 15000, this);
}
String queueCommand(String command) throws KeeperException {
String name = null;
while (true) {
try {
name = zk.create("/tasks/task-",
command.getBytes(),
ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT_SEQUENTIAL);
return name;
} catch (NodeExistsException e) {
LOG.error(name + " already appears to be running");
} catch (ConnectionLossException e) {
} catch (InterruptedException e) {
// TODO: handle exception
}
}
}
@Override
public void process(WatchedEvent event) {
// TODO Auto-generated method stub
}
}
四、AdminClient.java
package com.dayw.zk;
import java.util.Date;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.KeeperException.NoNodeException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.Stat;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class AdminClient implements Watcher {
private static final Logger LOG = LoggerFactory.getLogger(AdminClient.class);
ZooKeeper zk;
String hostPort;
AdminClient(String hostPort) {
this.hostPort = hostPort;
}
void start() throws Exception {
zk = new ZooKeeper(hostPort, 15000, this);
}
void listState() throws KeeperException, InterruptedException {
/** master */
try {
Stat stat = new Stat();
byte masterData[] = zk.getData("/master", false, stat);
Date startDate = new Date(stat.getCtime());
System.out.println("Master: " + new String(masterData) + " since " + startDate);
} catch (NoNodeException e) {
System.out.println("No Master");
}
/** Workers */
System.out.println("Workers:");
for (String w : zk.getChildren("/workers", false)) {
byte data[] = zk.getData("/workers/" + w, false, null);
String state = new String(data);
System.out.println("\t" + w + ": " + state);
}
/** Tasks */
System.out.println("Tasks:");
for (String t : zk.getChildren("/assign", false)) {
System.out.println("\t" + t);
}
}
@Override
public void process(WatchedEvent event) {
System.out.println(event);
}
public static void main(String args[]) throws Exception {
AdminClient c = new AdminClient(args[0]);
c.start();
c.listState();
}
}
