Java Code Examples for org.apache.zookeeper.ZooKeeper#getSessionId()

protected void simulateSessionExpiry(ZkConnection zkConnection)
    throws IOException, InterruptedException {
  ZooKeeper oldZookeeper = zkConnection.getZookeeper();
  LOG.info("Old sessionId = " + oldZookeeper.getSessionId());

  Watcher watcher = new Watcher() {
    @Override
    public void process(WatchedEvent event) {
      LOG.info("In New connection, process event:" + event);
    }
  };

  ZooKeeper newZookeeper =
      new ZooKeeper(zkConnection.getServers(), oldZookeeper.getSessionTimeout(), watcher,
          oldZookeeper.getSessionId(), oldZookeeper.getSessionPasswd());
  LOG.info("New sessionId = " + newZookeeper.getSessionId());
  // Thread.sleep(3000);
  newZookeeper.close();
  Thread.sleep(10000);
  oldZookeeper = zkConnection.getZookeeper();
  LOG.info("After session expiry sessionId = " + oldZookeeper.getSessionId());
}
 

private void expireZkSession(ZKClientService zkClientService) throws Exception {
  ZooKeeper zooKeeper = zkClientService.getZooKeeperSupplier().get();
  final SettableFuture<?> connectFuture = SettableFuture.create();
  Watcher watcher = new Watcher() {
    @Override
    public void process(WatchedEvent event) {
      if (event.getState() == Event.KeeperState.SyncConnected) {
        connectFuture.set(null);
      }
    }
  };

  // Create another Zookeeper session with the same sessionId so that the original one expires.
  ZooKeeper dupZookeeper =
    new ZooKeeper(zkClientService.getConnectString(), zooKeeper.getSessionTimeout(), watcher,
                  zooKeeper.getSessionId(), zooKeeper.getSessionPasswd());
  connectFuture.get(30, TimeUnit.SECONDS);
  Assert.assertEquals("Failed to re-create current session", dupZookeeper.getState(), ZooKeeper.States.CONNECTED);
  dupZookeeper.close();
}
 

/**
 * Kills a Zookeeper client to simulate failure scenarious during testing.
 * Callee will provide the amount of time to wait before it's considered failure
 * to kill a client.
 *
 * @param client that needs to be killed.
 * @param connectionString of Quorum
 * @param maxMs time in millisecond specifying the max time to kill a client.
 * @throws IOException When there is IO error
 * @throws InterruptedException When call has been interrupted.
 */
public static void kill(ZooKeeper client, String connectionString,
                        int maxMs) throws IOException, InterruptedException {
  final CountDownLatch latch = new CountDownLatch(1);
  ZooKeeper zk = new ZooKeeper(connectionString, maxMs, new Watcher() {
    @Override
    public void process(WatchedEvent event) {
      if (event.getState() == Event.KeeperState.SyncConnected) {
        latch.countDown();
      }
    }
  }, client.getSessionId(), client.getSessionPasswd());

  try {
    Preconditions.checkState(latch.await(maxMs, TimeUnit.MILLISECONDS), "Fail to kill ZK connection.");
  } finally {
    zk.close();
  }
}
 

private void expireZooKeeperSession(ZooKeeper zk, int timeout)
        throws IOException, InterruptedException, KeeperException {
    final CountDownLatch latch = new CountDownLatch(1);

    ZooKeeper newZk = new ZooKeeper(zkServers, timeout, new Watcher() {
        @Override
        public void process(WatchedEvent event) {
            if (event.getType() == EventType.None && event.getState() == KeeperState.SyncConnected) {
                latch.countDown();
            }
        }},
        zk.getSessionId(),
        zk.getSessionPasswd());

    if (!latch.await(timeout, TimeUnit.MILLISECONDS)) {
        throw KeeperException.create(KeeperException.Code.CONNECTIONLOSS);
    }

    newZk.close();
}
 

public static String createIfAbsent(ZooKeeper zk, String path, byte[] data, CreateMode createMode, boolean gc)
        throws KeeperException, InterruptedException {
    String pathCreated = null;
    try {
        pathCreated = zk.create(path, data, Ids.OPEN_ACL_UNSAFE, createMode);
    } catch (NodeExistsException e) {
        // OK
        LOG.debug("Create skipped for existing znode: path={}", path);
    }
    // reset if what exists is the ephemeral garbage.
    if (gc && (pathCreated == null) && CreateMode.EPHEMERAL.equals(createMode)) {
        Stat stat = zk.exists(path, false);
        if (stat != null && zk.getSessionId() != stat.getEphemeralOwner()) {
            deleteIfExists(zk, path, -1);
            pathCreated = zk.create(path, data, Ids.OPEN_ACL_UNSAFE, createMode);
        }
    }
    return pathCreated;
}
 

/**
 * Return the current session id
 */
public long getSessionId() {
    long sessionId = 0;
    try {
        ZooKeeper zk = zooKeeper.getZooKeeper();
        if (zk != null) {
            sessionId = zk.getSessionId();
        }
    } catch (Exception e) {
        // Ignore the exception
    }
    return sessionId;
}
 

/**
 * expire zk session asynchronously
 * @param client
 * @throws Exception
 */
public static void asyncExpireSession(RealmAwareZkClient client) throws Exception {
  final ZkClient zkClient = (ZkClient) client;
  ZkConnection connection = ((ZkConnection) zkClient.getConnection());
  ZooKeeper curZookeeper = connection.getZookeeper();
  LOG.info("Before expiry. sessionId: " + Long.toHexString(curZookeeper.getSessionId()));

  Watcher watcher = new Watcher() {
    @Override
    public void process(WatchedEvent event) {
      LOG.info("Process watchEvent: " + event);
    }
  };

  final ZooKeeper dupZookeeper =
      new ZooKeeper(connection.getServers(), curZookeeper.getSessionTimeout(), watcher,
          curZookeeper.getSessionId(), curZookeeper.getSessionPasswd());
  // wait until connected, then close
  while (dupZookeeper.getState() != States.CONNECTED) {
    Thread.sleep(10);
  }
  dupZookeeper.close();

  connection = (ZkConnection) zkClient.getConnection();
  curZookeeper = connection.getZookeeper();

  // System.err.println("zk: " + oldZookeeper);
  LOG.info("After expiry. sessionId: " + Long.toHexString(curZookeeper.getSessionId()));
}
 

@Test(timeout = 60000)
public void testZooKeeperReconnection() throws Exception {
    int sessionTimeoutMs = 100;
    ZooKeeperClient zkc = clientBuilder(sessionTimeoutMs).zkAclId(null).build();
    ZooKeeper zk = zkc.get();
    long sessionId = zk.getSessionId();
    ZooKeeperClientUtils.expireSession(zkc, zkServers, 2 * sessionTimeoutMs);
    ZooKeeper newZk = zkc.get();
    while (!ZooKeeper.States.CONNECTED.equals(newZk.getState())) {
        TimeUnit.MILLISECONDS.sleep(sessionTimeoutMs / 2);
    }
    long newSessionId = newZk.getSessionId();
    assertTrue(newZk == zk);
    assertFalse(sessionId == newSessionId);
}
 

/**
 * expire zk session asynchronously
 * @param client
 * @throws Exception
 */
public static void asyncExpireSession(RealmAwareZkClient client)
    throws Exception {
  final ZkClient zkClient = (ZkClient) client;
  ZkConnection connection = ((ZkConnection) zkClient.getConnection());
  ZooKeeper curZookeeper = connection.getZookeeper();
  LOG.info("Before expiry. sessionId: " + Long.toHexString(curZookeeper.getSessionId()));

  Watcher watcher = new Watcher() {
    @Override
    public void process(WatchedEvent event) {
      LOG.info("Process watchEvent: " + event);
    }
  };

  final ZooKeeper dupZookeeper =
      new ZooKeeper(connection.getServers(), curZookeeper.getSessionTimeout(), watcher,
          curZookeeper.getSessionId(), curZookeeper.getSessionPasswd());
  // wait until connected, then close
  while (dupZookeeper.getState() != States.CONNECTED) {
    Thread.sleep(10);
  }
  dupZookeeper.close();

  connection = (ZkConnection) zkClient.getConnection();
  curZookeeper = connection.getZookeeper();

  // System.err.println("zk: " + oldZookeeper);
  LOG.info("After expiry. sessionId: " + Long.toHexString(curZookeeper.getSessionId()));
}
 

@Test(timeout = 60000)
public void testZooKeeperReconnection() throws Exception {
    int sessionTimeoutMs = 100;
    ZooKeeperClient zkc = clientBuilder(sessionTimeoutMs).zkAclId(null).build();
    ZooKeeper zk = zkc.get();
    long sessionId = zk.getSessionId();
    ZooKeeperClientUtils.expireSession(zkc, zkServers, 2 * sessionTimeoutMs);
    ZooKeeper newZk = zkc.get();
    while (!ZooKeeper.States.CONNECTED.equals(newZk.getState())) {
        TimeUnit.MILLISECONDS.sleep(sessionTimeoutMs / 2);
    }
    long newSessionId = newZk.getSessionId();
    assertTrue(newZk == zk);
    assertFalse(sessionId == newSessionId);
}
 

/**
 * Check if the provided <i>path</i> exists or not and wait it expired if possible.
 *
 * @param zk the zookeeper client instance
 * @param path the zookeeper path
 * @param sessionTimeoutMs session timeout in milliseconds
 * @return true if path exists, otherwise return false
 * @throws KeeperException when failed to access zookeeper
 * @throws InterruptedException interrupted when waiting for znode to be expired
 */
public static boolean checkNodeAndWaitExpired(ZooKeeper zk,
                                              String path,
                                              long sessionTimeoutMs) throws KeeperException, InterruptedException {
    final CountDownLatch prevNodeLatch = new CountDownLatch(1);
    Watcher zkPrevNodeWatcher = watchedEvent -> {
        // check for prev node deletion.
        if (EventType.NodeDeleted == watchedEvent.getType()) {
            prevNodeLatch.countDown();
        }
    };
    Stat stat = zk.exists(path, zkPrevNodeWatcher);
    if (null != stat) {
        // if the ephemeral owner isn't current zookeeper client
        // wait for it to be expired
        if (stat.getEphemeralOwner() != zk.getSessionId()) {
            log.info("Previous znode : {} still exists, so waiting {} ms for znode deletion",
                path, sessionTimeoutMs);
            if (!prevNodeLatch.await(sessionTimeoutMs, TimeUnit.MILLISECONDS)) {
                throw new NodeExistsException(path);
            } else {
                return false;
            }
        }
        return true;
    } else {
        return false;
    }
}
 

@Test
public void testSessionExpire() throws Exception {
  assertArrayEquals(DATA, RO_ZK.get(PATH).get());
  ZooKeeper zk = RO_ZK.zookeeper;
  long sessionId = zk.getSessionId();
  UTIL.getZkCluster().getZooKeeperServers().get(0).closeSession(sessionId);
  // should not reach keep alive so still the same instance
  assertSame(zk, RO_ZK.zookeeper);
  byte[] got = RO_ZK.get(PATH).get();
  assertArrayEquals(DATA, got);
  assertNotNull(RO_ZK.zookeeper);
  assertNotSame(zk, RO_ZK.zookeeper);
  assertNotEquals(sessionId, RO_ZK.zookeeper.getSessionId());
}
 

protected void simulateSessionExpiry(HelixZkClient client)
    throws IOException, InterruptedException, IOException {
  ZkClient zkClient = (ZkClient) client;

  IZkStateListener listener = new IZkStateListener() {
    @Override
    public void handleStateChanged(Watcher.Event.KeeperState state) throws Exception {
      LOG.info("In Old connection, state changed:" + state);
    }

    @Override
    public void handleNewSession(final String sessionId) throws Exception {
      LOG.info("In Old connection, new session: {}.", sessionId);
    }

    @Override
    public void handleSessionEstablishmentError(Throwable var1) throws Exception {
    }
  };
  zkClient.subscribeStateChanges(listener);
  ZkConnection connection = ((ZkConnection) zkClient.getConnection());
  ZooKeeper oldZookeeper = connection.getZookeeper();
  LOG.info("Old sessionId = " + oldZookeeper.getSessionId());

  Watcher watcher = new Watcher() {
    @Override
    public void process(WatchedEvent event) {
      LOG.info("In New connection, process event:" + event);
    }
  };

  ZooKeeper newZookeeper =
      new ZooKeeper(connection.getServers(), oldZookeeper.getSessionTimeout(), watcher,
          oldZookeeper.getSessionId(), oldZookeeper.getSessionPasswd());
  LOG.info("New sessionId = " + newZookeeper.getSessionId());
  // Thread.sleep(3000);
  newZookeeper.close();
  Thread.sleep(10000);
  connection = (ZkConnection) zkClient.getConnection();
  oldZookeeper = connection.getZookeeper();
  LOG.info("After session expiry sessionId = " + oldZookeeper.getSessionId());
}
 

public static void expireSession(RealmAwareZkClient client) throws Exception {
  final CountDownLatch waitNewSession = new CountDownLatch(1);
  final ZkClient zkClient = (ZkClient) client;

  IZkStateListener listener = new IZkStateListener() {
    @Override
    public void handleStateChanged(KeeperState state) throws Exception {
      LOG.info("IZkStateListener#handleStateChanged, state: " + state);
    }

    @Override
    public void handleNewSession(final String sessionId) throws Exception {
      // make sure zkclient is connected again
      zkClient.waitUntilConnected(HelixZkClient.DEFAULT_CONNECTION_TIMEOUT, TimeUnit.SECONDS);

      LOG.info("handleNewSession. sessionId: {}.", sessionId);
      waitNewSession.countDown();
    }

    @Override
    public void handleSessionEstablishmentError(Throwable var1) throws Exception {
    }
  };

  zkClient.subscribeStateChanges(listener);

  ZkConnection connection = ((ZkConnection) zkClient.getConnection());
  ZooKeeper curZookeeper = connection.getZookeeper();
  String oldSessionId = Long.toHexString(curZookeeper.getSessionId());
  LOG.info("Before session expiry. sessionId: " + oldSessionId + ", zk: " + curZookeeper);

  Watcher watcher = new Watcher() {
    @Override
    public void process(WatchedEvent event) {
      LOG.info("Watcher#process, event: " + event);
    }
  };

  final ZooKeeper dupZookeeper =
      new ZooKeeper(connection.getServers(), curZookeeper.getSessionTimeout(), watcher,
          curZookeeper.getSessionId(), curZookeeper.getSessionPasswd());
  // wait until connected, then close
  while (dupZookeeper.getState() != States.CONNECTED) {
    Thread.sleep(10);
  }
  Assert.assertEquals(dupZookeeper.getState(), States.CONNECTED,
      "Fail to connect to zk using current session info");
  dupZookeeper.close();

  // make sure session expiry really happens
  waitNewSession.await();
  zkClient.unsubscribeStateChanges(listener);

  connection = (ZkConnection) zkClient.getConnection();
  curZookeeper = connection.getZookeeper();

  String newSessionId = Long.toHexString(curZookeeper.getSessionId());
  LOG.info("After session expiry. sessionId: " + newSessionId + ", zk: " + curZookeeper);
  Assert.assertFalse(newSessionId.equals(oldSessionId),
      "Fail to expire current session, zk: " + curZookeeper);
}
 

/**
 * Expire current zk session and wait for {@link IZkStateListener#handleNewSession(String)} invoked
 * @param client
 * @throws Exception
 */

public static void disconnectSession(HelixZkClient client) throws Exception {
  final ZkClient zkClient = (ZkClient) client;
  IZkStateListener listener = new IZkStateListener() {
    @Override
    public void handleStateChanged(KeeperState state) throws Exception {
      // System.err.println("disconnectSession handleStateChanged. state: " + state);
    }

    @Override
    public void handleNewSession(final String sessionId) throws Exception {
      // make sure zkclient is connected again
      zkClient.waitUntilConnected(HelixZkClient.DEFAULT_CONNECTION_TIMEOUT, TimeUnit.SECONDS);

      LOG.info("handleNewSession. sessionId: {}.", sessionId);
    }

    @Override
    public void handleSessionEstablishmentError(Throwable var1) throws Exception {
    }
  };

  zkClient.subscribeStateChanges(listener);
  ZkConnection connection = (ZkConnection) zkClient.getConnection();
  ZooKeeper curZookeeper = connection.getZookeeper();
  LOG.info("Before expiry. sessionId: " + Long.toHexString(curZookeeper.getSessionId()));

  Watcher watcher = new Watcher() {
    @Override
    public void process(WatchedEvent event) {
      LOG.info("Process watchEvent: " + event);
    }
  };

  final ZooKeeper dupZookeeper =
      new ZooKeeper(connection.getServers(), curZookeeper.getSessionTimeout(), watcher,
          curZookeeper.getSessionId(), curZookeeper.getSessionPasswd());
  // wait until connected, then close
  while (dupZookeeper.getState() != States.CONNECTED) {
    Thread.sleep(10);
  }
  dupZookeeper.close();

  connection = (ZkConnection) zkClient.getConnection();
  curZookeeper = connection.getZookeeper();
  zkClient.unsubscribeStateChanges(listener);

  // System.err.println("zk: " + oldZookeeper);
  LOG.info("After expiry. sessionId: " + Long.toHexString(curZookeeper.getSessionId()));
}
 

public static void expireSession(RealmAwareZkClient client)
    throws Exception {
  final CountDownLatch waitNewSession = new CountDownLatch(1);
  final ZkClient zkClient = (ZkClient) client;

  IZkStateListener listener = new IZkStateListener() {
    @Override
    public void handleStateChanged(KeeperState state)
        throws Exception {
      LOG.info("IZkStateListener#handleStateChanged, state: " + state);
    }

    @Override
    public void handleNewSession(final String sessionId)
        throws Exception {
      // make sure zkclient is connected again
      zkClient.waitUntilConnected(HelixZkClient.DEFAULT_CONNECTION_TIMEOUT, TimeUnit.SECONDS);

      LOG.info("handleNewSession. sessionId: {}.", sessionId);
      waitNewSession.countDown();
    }

    @Override
    public void handleSessionEstablishmentError(Throwable var1)
        throws Exception {
    }
  };

  zkClient.subscribeStateChanges(listener);

  ZkConnection connection = ((ZkConnection) zkClient.getConnection());
  ZooKeeper curZookeeper = connection.getZookeeper();
  String oldSessionId = Long.toHexString(curZookeeper.getSessionId());
  LOG.info("Before session expiry. sessionId: " + oldSessionId + ", zk: " + curZookeeper);

  Watcher watcher = new Watcher() {
    @Override
    public void process(WatchedEvent event) {
      LOG.info("Watcher#process, event: " + event);
    }
  };

  final ZooKeeper dupZookeeper =
      new ZooKeeper(connection.getServers(), curZookeeper.getSessionTimeout(), watcher,
          curZookeeper.getSessionId(), curZookeeper.getSessionPasswd());
  // wait until connected, then close
  while (dupZookeeper.getState() != States.CONNECTED) {
    Thread.sleep(10);
  }
  Assert.assertEquals(dupZookeeper.getState(), States.CONNECTED,
      "Fail to connect to zk using current session info");
  dupZookeeper.close();

  // make sure session expiry really happens
  waitNewSession.await();
  zkClient.unsubscribeStateChanges(listener);

  connection = (ZkConnection) zkClient.getConnection();
  curZookeeper = connection.getZookeeper();

  String newSessionId = Long.toHexString(curZookeeper.getSessionId());
  LOG.info("After session expiry. sessionId: " + newSessionId + ", zk: " + curZookeeper);
  Assert.assertFalse(newSessionId.equals(oldSessionId),
      "Fail to expire current session, zk: " + curZookeeper);
}
 

/**
 * Expire a ZooKeeper session as recommended in ZooKeeper documentation
 * http://hbase.apache.org/book.html#trouble.zookeeper
 * There are issues when doing this:
 * [1] http://www.mail-archive.com/[email protected]/msg01942.html
 * [2] https://issues.apache.org/jira/browse/ZOOKEEPER-1105
 *
 * @param nodeZK - the ZK watcher to expire
 * @param checkStatus - true to check if we can create a Table with the
 *                    current configuration.
 */
public void expireSession(ZKWatcher nodeZK, boolean checkStatus)
  throws Exception {
  Configuration c = new Configuration(this.conf);
  String quorumServers = ZKConfig.getZKQuorumServersString(c);
  ZooKeeper zk = nodeZK.getRecoverableZooKeeper().getZooKeeper();
  byte[] password = zk.getSessionPasswd();
  long sessionID = zk.getSessionId();

  // Expiry seems to be asynchronous (see comment from P. Hunt in [1]),
  //  so we create a first watcher to be sure that the
  //  event was sent. We expect that if our watcher receives the event
  //  other watchers on the same machine will get is as well.
  // When we ask to close the connection, ZK does not close it before
  //  we receive all the events, so don't have to capture the event, just
  //  closing the connection should be enough.
  ZooKeeper monitor = new ZooKeeper(quorumServers,
    1000, new org.apache.zookeeper.Watcher(){
    @Override
    public void process(WatchedEvent watchedEvent) {
      LOG.info("Monitor ZKW received event="+watchedEvent);
    }
  } , sessionID, password);

  // Making it expire
  ZooKeeper newZK = new ZooKeeper(quorumServers,
      1000, EmptyWatcher.instance, sessionID, password);

  //ensure that we have connection to the server before closing down, otherwise
  //the close session event will be eaten out before we start CONNECTING state
  long start = System.currentTimeMillis();
  while (newZK.getState() != States.CONNECTED
       && System.currentTimeMillis() - start < 1000) {
     Thread.sleep(1);
  }
  newZK.close();
  LOG.info("ZK Closed Session 0x" + Long.toHexString(sessionID));

  // Now closing & waiting to be sure that the clients get it.
  monitor.close();

  if (checkStatus) {
    getConnection().getTable(TableName.META_TABLE_NAME).close();
  }
}
 

@Override
public Long getSessionId() {
  ZooKeeper zk = zooKeeper.get();
  return zk == null ? null : zk.getSessionId();
}
 

@Override
public Long getSessionId() {
  ZooKeeper zk = zooKeeper.get();
  return zk == null ? null : zk.getSessionId();
}
 

/**
 * Expire current zk session and wait for {@link IZkStateListener#handleNewSession(String)} invoked
 * @param client
 * @throws Exception
 */
public static void disconnectSession(HelixZkClient client)
    throws Exception {
  final ZkClient zkClient = (ZkClient) client;
  IZkStateListener listener = new IZkStateListener() {
    @Override
    public void handleStateChanged(KeeperState state)
        throws Exception {
      // System.err.println("disconnectSession handleStateChanged. state: " + state);
    }

    @Override
    public void handleNewSession(final String sessionId)
        throws Exception {
      // make sure zkclient is connected again
      zkClient.waitUntilConnected(HelixZkClient.DEFAULT_CONNECTION_TIMEOUT, TimeUnit.SECONDS);

      LOG.info("handleNewSession. sessionId: {}.", sessionId);
    }

    @Override
    public void handleSessionEstablishmentError(Throwable var1)
        throws Exception {
    }
  };

  zkClient.subscribeStateChanges(listener);
  ZkConnection connection = (ZkConnection) zkClient.getConnection();
  ZooKeeper curZookeeper = connection.getZookeeper();
  LOG.info("Before expiry. sessionId: " + Long.toHexString(curZookeeper.getSessionId()));

  Watcher watcher = new Watcher() {
    @Override
    public void process(WatchedEvent event) {
      LOG.info("Process watchEvent: " + event);
    }
  };

  final ZooKeeper dupZookeeper =
      new ZooKeeper(connection.getServers(), curZookeeper.getSessionTimeout(), watcher,
          curZookeeper.getSessionId(), curZookeeper.getSessionPasswd());
  // wait until connected, then close
  while (dupZookeeper.getState() != States.CONNECTED) {
    Thread.sleep(10);
  }
  dupZookeeper.close();

  connection = (ZkConnection) zkClient.getConnection();
  curZookeeper = connection.getZookeeper();
  zkClient.unsubscribeStateChanges(listener);

  // System.err.println("zk: " + oldZookeeper);
  LOG.info("After expiry. sessionId: " + Long.toHexString(curZookeeper.getSessionId()));
}