Java Code Examples for org.apache.curator.framework.recipes.leader.LeaderLatch#start()

@Override
public void run(String... strings) throws Exception {
    LeaderLatch leaderLatch = new LeaderLatch(client, path);
    leaderLatch.addListener(new LeaderLatchListener() {
        @Override
        public void isLeader() {
            MasterInfo.setIsMaster(true);
            refreshLeaderIp();
            scheduler.start();
        }

        @Override
        public void notLeader() {
            MasterInfo.setIsMaster(false);
            scheduler.stop();
            EventQueue.clear();
        }
    });
    leaderLatch.start();
}
 

@Override
public void elect() throws Exception {
	
	zkClient.createContainers(ctx.getLeaderElectionZKPath());
	
	latch = new LeaderLatch(zkClient, ctx.getLeaderElectionZKPath(), ctx.getLeaderElectionID());
	latch.addListener(new LeaderLatchListener() {

		@Override
		public void notLeader() {
		}

		@Override
		public void isLeader() {
		}
	});

	latch.start();
	logger.info("[elect]{}", ctx);
}
 

protected void startAgent(String baseUrl, String group) {
  try {
    BaragonAgentMetadata agentMetadata = new BaragonAgentMetadata(
        baseUrl,
        UUID.randomUUID().toString(),
        Optional.absent(),
        null,
        Optional.absent(),
        null,
        true);
    LeaderLatch leaderLatch = loadBalancerDatastore.createLeaderLatch(group, agentMetadata);
    String id = leaderLatch.getId();
    leaderLatch.start();
    activeLeaderLatch.add(leaderLatch);
    while (leaderLatch.getParticipants().stream().map(Participant::getId).noneMatch(id::equals)) {
      Thread.sleep(5);
    }
  } catch (Throwable t) {
    throw new RuntimeException(t);
  }
}
 

public synchronized void registerLeaderLatch() throws Exception {
    if (zkClient.checkExists().forPath(getLeaderPath()) == null) {
        zkClient.create().forPath(getLeaderPath());
    }
    leaderLatch = new LeaderLatch(zkClient, getLeaderPath(), hostName);
    leaderLatch.start();

    log.info("leaderLatch start");
}
 

public synchronized void registerLeaderLatch() throws Exception {
    if (zkClient.checkExists().forPath(getLeaderPath()) == null) {
        zkClient.create().forPath(getLeaderPath());
    }
    leaderLatch = new LeaderLatch(zkClient, getLeaderPath(), hostName);
    leaderLatch.start();

    log.info("leaderLatch start");
}
 

private void init(){
	CuratorFramework client = CuratorFrameworkFactory.newClient(zooKeeperUrl, new RetryForever(1000));
	leaderLatch = new LeaderLatch(client, "/EasyTransMasterSelector"+"/" + applicationName);
	try {
		client.start();
		leaderLatch.start();
	} catch (Exception e) {
		throw new RuntimeException(e);
	}
}
 

@SuppressWarnings("resource")
@Override
public void process() {
    try {
        CuratorFramework _curator = CuratorContainer.getInstance().getCurator();
        ZkVo conf = HeartBeatConfigContainer.getInstance().getZkConf();
        CuratorContainer.getInstance().createZkNode(conf.getLeaderPath());

        // 获取进程ID和服务器hostName
        final BrokerInfoVo brokerInfo = new BrokerInfoVo();
        String name = ManagementFactory.getRuntimeMXBean().getName();
        String[] pidAndHostName = StringUtils.split(name, "@");
        brokerInfo.setPid(pidAndHostName[0]);
        brokerInfo.setHostName(pidAndHostName[1]);
        brokerInfo.setIp(InetAddress.getLocalHost().getHostAddress());
        LeaderLatch ll = new LeaderLatch(_curator, conf.getLeaderPath(), JsonUtil.toJson(brokerInfo));

        ll.addListener(new LeaderLatchListener() {
            @Override
            public void notLeader() {
                LoggerFactory.getLogger().error("本机现在切换到非leader状态,准备终止当前进程PID:{}", brokerInfo.getPid());
                System.exit(-1);
            }

            @Override
            public void isLeader() {
                LoggerFactory.getLogger().info("本机现在切换到leader状态.");
            }
        });

        ll.start();
        ll.await();
    } catch (Exception e) {
        throw new RuntimeException("选举leader时发生错误!", e);
    }
}
 

/**
 * 阻塞式的初始化和Zookeeper的连接，这个方法在一个容器生命周期中只允许允许一次。
 * <p/>
 * 和zookeeper之间的连接遵循每实例一个ZkClientProvider的方式，这样当实例内部有多个同步线程的时候，
 * 可以共享一个ZkClientProvider，状态都是一致的，避免有些线程是leader，有些是standby的情况。
 * <p/>
 * 改方法是全异步的，如果zookeeper连接不上，也会返回。但是一般上层应用拿不到leader latch，不会成为leader。
 * 而且<code>apache.zookeeper.ClientCnxn</code>包的日志会打印如下：
 * <pre>
 *     Unable to read additional data from server sessionid 0x0, likely server has closed socket, closing socket
 *     connection and attempting reconnect
 * </pre>
 * 参数<code>name</code>标示同步线程的名称，默认的话只有一个可以初始化好和zk的连接，其他的都不再重复初始化了。
 */
@Override
public void init(String name) {
    if (!state.compareAndSet(State.LATENT, State.STARTED)) {
        logger.debug("ZkHaGuard can only be initialized once because LeaderLatch should be singleton");
        return;
    }

    if (zkClientProvider == null) {
        throw new IllegalStateException("ZkClientProvider should not be null");
    }
    logger.info("LeaderLatch will start soon by " + name);
    zkClientProvider.init();
    leaderLatch = new LeaderLatch(zkClientProvider.provideClient(), latchPath, NetUtils.getLocalHostIP());
    leaderLatch.addListener(new LeaderLatchListener() {
        @Override
        public void isLeader() {
            logger.info("This instance is leader");
        }

        @Override
        public void notLeader() {
            logger.warn("This instance is NOT leader");
        }
    });
    try {
        leaderLatch.start();
    } catch (Exception e) {
        throw new RuntimeException("Leader latch init failed", e);
    }
    logger.info("LeaderLatch starts by " + name + " asynchronously");
}
 

public void start() throws Exception {
    client.start();
    client.getZookeeperClient().blockUntilConnectedOrTimedOut();
    leaderLatch = new LeaderLatch(client, latchpath, id);

    ClusterSyncManagerLeaderListener listener = new ClusterSyncManagerLeaderListener(failOverTask, getNode());
    leaderLatch.addListener(listener);

    leaderLatch.start();
}
 

private synchronized LeaderLatch startLeaderLatch() throws InterruptedException {
    LeaderLatch latch = _latch; // Read the volatile once
    // Assert not started already.  initLeaderLatch() and closeLeaderLatch() leave the latch in the latent state.
    checkState(latch.getState() == LeaderLatch.State.LATENT);
    try {
        latch.start();
    } catch (InterruptedException ie) {
        throw ie;
    } catch (Throwable t) {
        LOG.error("Exception attempting to acquire leadership: {}", getId(), t);
    }
    return latch;
}
 

public void start() throws Exception {
    client.start();
    client.getZookeeperClient().blockUntilConnectedOrTimedOut();
    leaderLatch = new LeaderLatch(client, latchpath, id);
    leaderLatch.start();
}
 

public synchronized void start() throws Exception {
  if (started) {
    throw new IllegalStateException();
  }

  curatorFramework = CuratorUtil.newAppCurator(env.getConfiguration());
  curatorFramework.getConnectionStateListenable().addListener(cnxnListener);
  curatorFramework.start();

  while (!cnxnListener.isConnected()) {
    UtilWaitThread.sleep(200);
  }

  final InetSocketAddress addr = startServer();

  String leaderId = HostUtil.getHostName() + ":" + addr.getPort();
  leaderLatch = new LeaderLatch(curatorFramework, ZookeeperPath.ORACLE_SERVER, leaderId);
  log.info("Leader ID = " + leaderId);
  execService = Executors.newSingleThreadExecutor(new FluoThreadFactory("Oracle Server Worker"));
  leaderLatch.addListener(new LeaderLatchListener() {
    @Override
    public void notLeader() {
      isLeader = false;

      if (started) {
        // if we stopped the server manually, we shouldn't halt
        Halt.halt("Oracle has lost leadership unexpectedly and is now halting.");
      }
    }

    @Override
    public void isLeader() {
      assumeLeadership();
    }
  }, execService);
  leaderLatch.start();

  pathChildrenCache = new PathChildrenCache(curatorFramework, oraclePath, true);
  pathChildrenCache.getListenable().addListener(this);
  pathChildrenCache.start();

  while (!cnxnListener.isConnected()) {
    UtilWaitThread.sleep(200);
  }

  log.info("Listening " + addr);

  started = true;
}