Examples with WatchedEvent org.apache.zookeeper.WatchedEvent used on opensource projects

Example 36 with WatchedEvent

use of org.apache.zookeeper.WatchedEvent in project pulsar by yahoo.

the class ZooKeeperSessionWatcherTest method testProcess1.

@Test
void testProcess1() {
    WatchedEvent event = new WatchedEvent(EventType.None, KeeperState.Expired, null);
    sessionWatcher.process(event);
    assertTrue(sessionWatcher.isShutdownStarted());
    assertEquals(shutdownService.getExitCode(), -1);
}

Example 37 with WatchedEvent

use of org.apache.zookeeper.WatchedEvent in project pulsar by yahoo.

the class ZooKeeperSessionWatcherTest method testProcess2.

@Test
void testProcess2() {
    WatchedEvent event = new WatchedEvent(EventType.None, KeeperState.Disconnected, null);
    sessionWatcher.process(event);
    assertFalse(sessionWatcher.isShutdownStarted());
    assertEquals(shutdownService.getExitCode(), 0);
}

Example 38 with WatchedEvent

use of org.apache.zookeeper.WatchedEvent in project pulsar by yahoo.

the class ZooKeeperSessionWatcherTest method testProcess3.

@Test
void testProcess3() {
    WatchedEvent event = new WatchedEvent(EventType.NodeCreated, KeeperState.Expired, null);
    sessionWatcher.process(event);
    assertFalse(sessionWatcher.isShutdownStarted());
    assertEquals(shutdownService.getExitCode(), 0);
}

Example 39 with WatchedEvent

use of org.apache.zookeeper.WatchedEvent in project pulsar by yahoo.

the class ZookeeperCacheTest method testGlobalZooKeeperCache.

@Test
void testGlobalZooKeeperCache() throws Exception {
    OrderedSafeExecutor executor = new OrderedSafeExecutor(1, "test");
    ScheduledExecutorService scheduledExecutor = new ScheduledThreadPoolExecutor(1);
    MockZooKeeper zkc = MockZooKeeper.newInstance();
    ZooKeeperClientFactory zkClientfactory = new ZooKeeperClientFactory() {

        @Override
        public CompletableFuture<ZooKeeper> create(String serverList, SessionType sessionType, int zkSessionTimeoutMillis) {
            return CompletableFuture.completedFuture(zkc);
        }
    };
    GlobalZooKeeperCache zkCacheService = new GlobalZooKeeperCache(zkClientfactory, -1, "", executor, scheduledExecutor);
    zkCacheService.start();
    zkClient = (MockZooKeeper) zkCacheService.getZooKeeper();
    ZooKeeperDataCache<String> zkCache = new ZooKeeperDataCache<String>(zkCacheService) {

        @Override
        public String deserialize(String key, byte[] content) throws Exception {
            return new String(content);
        }
    };
    // Create callback counter
    AtomicInteger notificationCount = new AtomicInteger(0);
    ZooKeeperCacheListener<String> counter = (path, data, stat) -> {
        notificationCount.incrementAndGet();
    };
    // Register counter twice and unregister once, so callback should be counted correctly
    zkCache.registerListener(counter);
    zkCache.registerListener(counter);
    zkCache.unregisterListener(counter);
    String value = "test";
    zkClient.create("/my_test", value.getBytes(), null, null);
    assertEquals(zkCache.get("/my_test").get(), value);
    String newValue = "test2";
    // case 1: update and create znode directly and verify that the cache is retrieving the correct data
    assertEquals(notificationCount.get(), 0);
    zkClient.setData("/my_test", newValue.getBytes(), -1);
    zkClient.create("/my_test2", value.getBytes(), null, null);
    // Wait for the watch to be triggered
    while (notificationCount.get() < 1) {
        Thread.sleep(1);
    }
    // retrieve the data from the cache and verify it is the updated/new data
    assertEquals(zkCache.get("/my_test").get(), newValue);
    assertEquals(zkCache.get("/my_test2").get(), value);
    // The callback method should be called just only once
    assertEquals(notificationCount.get(), 1);
    // case 2: force the ZooKeeper session to be expired and verify that the data is still accessible
    zkCacheService.process(new WatchedEvent(Event.EventType.None, KeeperState.Expired, null));
    assertEquals(zkCache.get("/my_test").get(), newValue);
    assertEquals(zkCache.get("/my_test2").get(), value);
    // case 3: update the znode directly while the client session is marked as expired. Verify that the new updates
    // is not seen in the cache
    zkClient.create("/other", newValue.getBytes(), null, null);
    zkClient.failNow(Code.SESSIONEXPIRED);
    assertEquals(zkCache.get("/my_test").get(), newValue);
    assertEquals(zkCache.get("/my_test2").get(), value);
    try {
        zkCache.get("/other");
        fail("shuld have thrown exception");
    } catch (Exception e) {
    // Ok
    }
    // case 4: directly delete the znode while the session is not re-connected yet. Verify that the deletion is not
    // seen by the cache
    zkClient.failAfter(-1, Code.OK);
    zkClient.delete("/my_test2", -1);
    zkCacheService.process(new WatchedEvent(Event.EventType.None, KeeperState.SyncConnected, null));
    assertEquals(zkCache.get("/other").get(), newValue);
    // Make sure that the value is now directly from ZK and deleted
    assertFalse(zkCache.get("/my_test2").isPresent());
    // case 5: trigger a ZooKeeper disconnected event and make sure the cache content is not changed.
    zkCacheService.process(new WatchedEvent(Event.EventType.None, KeeperState.Disconnected, null));
    zkClient.create("/other2", newValue.getBytes(), null, null);
    // case 6: trigger a ZooKeeper SyncConnected event and make sure that the cache content is invalidated s.t. we
    // can see the updated content now
    zkCacheService.process(new WatchedEvent(Event.EventType.None, KeeperState.SyncConnected, null));
    // make sure that we get it
    assertEquals(zkCache.get("/other2").get(), newValue);
    zkCacheService.close();
    executor.shutdown();
    // Update shouldn't happen after the last check
    assertEquals(notificationCount.get(), 1);
}

Example 40 with WatchedEvent

use of org.apache.zookeeper.WatchedEvent in project pulsar by yahoo.

the class LeaderElectionService method elect.

/**
     * We try to get the data in the ELECTION_ROOT node. If the node is present (i.e. leader is present), we store it in
     * the currentLeader and keep a watch on the election node. If we lose the leader, then watch gets triggered and we
     * do the election again. If the node does not exist while getting the data, we get NoNodeException. This means,
     * there is no leader and we create the node at ELECTION_ROOT and write the leader broker's service URL in the node.
     * Once the leader is known, we call the listener method so that leader can take further actions.
     */
private void elect() {
    try {
        byte[] data = zkClient.getData(ELECTION_ROOT, new Watcher() {

            @Override
            public void process(WatchedEvent event) {
                log.warn("Type of the event is [{}] and path is [{}]", event.getType(), event.getPath());
                switch(event.getType()) {
                    case NodeDeleted:
                        log.warn("Election node {} is deleted, attempting re-election...", event.getPath());
                        if (event.getPath().equals(ELECTION_ROOT)) {
                            log.info("This should call elect again...");
                            executor.execute(new Runnable() {

                                @Override
                                public void run() {
                                    // If the node is deleted, attempt the re-election
                                    log.info("Broker [{}] is calling re-election from the thread", pulsar.getWebServiceAddress());
                                    elect();
                                }
                            });
                        }
                        break;
                    default:
                        log.warn("Got something wrong on watch: {}", event);
                        break;
                }
            }
        }, null);
        LeaderBroker leaderBroker = jsonMapper.readValue(data, LeaderBroker.class);
        currentLeader.set(leaderBroker);
        isLeader.set(false);
        leaderListener.brokerIsAFollowerNow();
        // If broker comes here it is a follower. Do nothing, wait for the watch to trigger
        log.info("Broker [{}] is the follower now. Waiting for the watch to trigger...", pulsar.getWebServiceAddress());
    } catch (NoNodeException nne) {
        // There's no leader yet... try to become the leader
        try {
            // Create the root node and add current broker's URL as its contents
            LeaderBroker leaderBroker = new LeaderBroker(pulsar.getWebServiceAddress());
            ZkUtils.createFullPathOptimistic(pulsar.getLocalZkCache().getZooKeeper(), ELECTION_ROOT, jsonMapper.writeValueAsBytes(leaderBroker), Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL);
            // Update the current leader and set the flag to true
            currentLeader.set(new LeaderBroker(leaderBroker.getServiceUrl()));
            isLeader.set(true);
            // Notify the listener that this broker is now the leader so that it can collect usage and start load
            // manager.
            log.info("Broker [{}] is the leader now, notifying the listener...", pulsar.getWebServiceAddress());
            leaderListener.brokerIsTheLeaderNow();
        } catch (NodeExistsException nee) {
            // Re-elect the new leader
            log.warn("Got exception [{}] while creating election node because it already exists. Attempting re-election...", nee.getMessage());
            executor.execute(new Runnable() {

                @Override
                public void run() {
                    elect();
                }
            });
        } catch (Exception e) {
            // Kill the broker because this broker's session with zookeeper might be stale. Killing the broker will
            // make sure that we get the fresh zookeeper session.
            log.error("Got exception [{}] while creating the election node", e.getMessage());
            pulsar.getShutdownService().shutdown(-1);
        }
    } catch (Exception e) {
        // Kill the broker
        log.error("Could not get the content of [{}], got exception [{}]. Shutting down the broker...", ELECTION_ROOT, e);
        pulsar.getShutdownService().shutdown(-1);
    }
}