Examples with PathChildrenCache org.apache.curator.framework.recipes.cache.PathChildrenCache used on opensource projects

Example 41 with PathChildrenCache

use of org.apache.curator.framework.recipes.cache.PathChildrenCache in project druid by druid-io.

the class RemoteTaskRunner method addWorker.

/**
   * When a new worker appears, listeners are registered for status changes associated with tasks assigned to
   * the worker. Status changes indicate the creation or completion of a task.
   * The RemoteTaskRunner updates state according to these changes.
   *
   * @param worker contains metadata for a worker that has appeared in ZK
   *
   * @return future that will contain a fully initialized worker
   */
private ListenableFuture<ZkWorker> addWorker(final Worker worker) {
    log.info("Worker[%s] reportin' for duty!", worker.getHost());
    try {
        cancelWorkerCleanup(worker.getHost());
        final String workerStatusPath = JOINER.join(indexerZkConfig.getStatusPath(), worker.getHost());
        final PathChildrenCache statusCache = workerStatusPathChildrenCacheFactory.make(cf, workerStatusPath);
        final SettableFuture<ZkWorker> retVal = SettableFuture.create();
        final ZkWorker zkWorker = new ZkWorker(worker, statusCache, jsonMapper);
        // Add status listener to the watcher for status changes
        zkWorker.addListener(new PathChildrenCacheListener() {

            @Override
            public void childEvent(CuratorFramework client, PathChildrenCacheEvent event) throws Exception {
                final String taskId;
                final RemoteTaskRunnerWorkItem taskRunnerWorkItem;
                synchronized (statusLock) {
                    try {
                        switch(event.getType()) {
                            case CHILD_ADDED:
                            case CHILD_UPDATED:
                                taskId = ZKPaths.getNodeFromPath(event.getData().getPath());
                                final TaskAnnouncement announcement = jsonMapper.readValue(event.getData().getData(), TaskAnnouncement.class);
                                log.info("Worker[%s] wrote %s status for task [%s] on [%s]", zkWorker.getWorker().getHost(), announcement.getTaskStatus().getStatusCode(), taskId, announcement.getTaskLocation());
                                // Synchronizing state with ZK
                                statusLock.notifyAll();
                                final RemoteTaskRunnerWorkItem tmp;
                                if ((tmp = runningTasks.get(taskId)) != null) {
                                    taskRunnerWorkItem = tmp;
                                } else {
                                    final RemoteTaskRunnerWorkItem newTaskRunnerWorkItem = new RemoteTaskRunnerWorkItem(taskId, zkWorker.getWorker(), TaskLocation.unknown());
                                    final RemoteTaskRunnerWorkItem existingItem = runningTasks.putIfAbsent(taskId, newTaskRunnerWorkItem);
                                    if (existingItem == null) {
                                        log.warn("Worker[%s] announced a status for a task I didn't know about, adding to runningTasks: %s", zkWorker.getWorker().getHost(), taskId);
                                        taskRunnerWorkItem = newTaskRunnerWorkItem;
                                    } else {
                                        taskRunnerWorkItem = existingItem;
                                    }
                                }
                                if (!announcement.getTaskLocation().equals(taskRunnerWorkItem.getLocation())) {
                                    taskRunnerWorkItem.setLocation(announcement.getTaskLocation());
                                    TaskRunnerUtils.notifyLocationChanged(listeners, taskId, announcement.getTaskLocation());
                                }
                                if (announcement.getTaskStatus().isComplete()) {
                                    taskComplete(taskRunnerWorkItem, zkWorker, announcement.getTaskStatus());
                                    runPendingTasks();
                                }
                                break;
                            case CHILD_REMOVED:
                                taskId = ZKPaths.getNodeFromPath(event.getData().getPath());
                                taskRunnerWorkItem = runningTasks.remove(taskId);
                                if (taskRunnerWorkItem != null) {
                                    log.info("Task[%s] just disappeared!", taskId);
                                    taskRunnerWorkItem.setResult(TaskStatus.failure(taskId));
                                    TaskRunnerUtils.notifyStatusChanged(listeners, taskId, TaskStatus.failure(taskId));
                                } else {
                                    log.info("Task[%s] went bye bye.", taskId);
                                }
                                break;
                            case INITIALIZED:
                                if (zkWorkers.putIfAbsent(worker.getHost(), zkWorker) == null) {
                                    retVal.set(zkWorker);
                                } else {
                                    final String message = String.format("WTF?! Tried to add already-existing worker[%s]", worker.getHost());
                                    log.makeAlert(message).addData("workerHost", worker.getHost()).addData("workerIp", worker.getIp()).emit();
                                    retVal.setException(new IllegalStateException(message));
                                }
                                runPendingTasks();
                        }
                    } catch (Exception e) {
                        log.makeAlert(e, "Failed to handle new worker status").addData("worker", zkWorker.getWorker().getHost()).addData("znode", event.getData().getPath()).emit();
                    }
                }
            }
        });
        zkWorker.start();
        return retVal;
    } catch (Exception e) {
        throw Throwables.propagate(e);
    }
}

Example 42 with PathChildrenCache

use of org.apache.curator.framework.recipes.cache.PathChildrenCache in project druid by druid-io.

the class DruidCoordinatorTest method setUp.

@Before
public void setUp() throws Exception {
    taskMaster = EasyMock.createMock(LoadQueueTaskMaster.class);
    druidServer = EasyMock.createMock(DruidServer.class);
    serverInventoryView = EasyMock.createMock(SingleServerInventoryView.class);
    databaseSegmentManager = EasyMock.createNiceMock(MetadataSegmentManager.class);
    metadataRuleManager = EasyMock.createNiceMock(MetadataRuleManager.class);
    configManager = EasyMock.createNiceMock(JacksonConfigManager.class);
    EasyMock.expect(configManager.watch(EasyMock.anyString(), EasyMock.anyObject(Class.class), EasyMock.anyObject())).andReturn(new AtomicReference(new CoordinatorDynamicConfig.Builder().build())).anyTimes();
    EasyMock.replay(configManager);
    setupServerAndCurator();
    curator.start();
    curator.blockUntilConnected();
    curator.create().creatingParentsIfNeeded().forPath(LOADPATH);
    objectMapper = new DefaultObjectMapper();
    druidCoordinatorConfig = new TestDruidCoordinatorConfig(new Duration(COORDINATOR_START_DELAY), new Duration(COORDINATOR_PERIOD), null, null, new Duration(COORDINATOR_PERIOD), null, 10, null, false, false, new Duration("PT0s"));
    pathChildrenCache = new PathChildrenCache(curator, LOADPATH, true, true, Execs.singleThreaded("coordinator_test_path_children_cache-%d"));
    loadQueuePeon = new LoadQueuePeon(curator, LOADPATH, objectMapper, Execs.scheduledSingleThreaded("coordinator_test_load_queue_peon_scheduled-%d"), Execs.singleThreaded("coordinator_test_load_queue_peon-%d"), druidCoordinatorConfig);
    loadQueuePeon.start();
    druidNode = new DruidNode("hey", "what", 1234);
    loadManagementPeons = new MapMaker().makeMap();
    scheduledExecutorFactory = new ScheduledExecutorFactory() {

        @Override
        public ScheduledExecutorService create(int corePoolSize, final String nameFormat) {
            return Executors.newSingleThreadScheduledExecutor();
        }
    };
    leaderAnnouncerLatch = new CountDownLatch(1);
    leaderUnannouncerLatch = new CountDownLatch(1);
    coordinator = new DruidCoordinator(druidCoordinatorConfig, new ZkPathsConfig() {

        @Override
        public String getBase() {
            return "druid";
        }
    }, configManager, databaseSegmentManager, serverInventoryView, metadataRuleManager, curator, new NoopServiceEmitter(), scheduledExecutorFactory, null, taskMaster, new NoopServiceAnnouncer() {

        @Override
        public void announce(DruidNode node) {
            // count down when this coordinator becomes the leader
            leaderAnnouncerLatch.countDown();
        }

        @Override
        public void unannounce(DruidNode node) {
            leaderUnannouncerLatch.countDown();
        }
    }, druidNode, loadManagementPeons, null, new CostBalancerStrategyFactory());
}

Example 43 with PathChildrenCache

use of org.apache.curator.framework.recipes.cache.PathChildrenCache in project druid by druid-io.

the class LoadQueuePeonTest method setUp.

@Before
public void setUp() throws Exception {
    setupServerAndCurator();
    curator.start();
    curator.blockUntilConnected();
    curator.create().creatingParentsIfNeeded().forPath(LOAD_QUEUE_PATH);
    loadQueueCache = new PathChildrenCache(curator, LOAD_QUEUE_PATH, true, true, Execs.singleThreaded("load_queue_cache-%d"));
}

Example 44 with PathChildrenCache

use of org.apache.curator.framework.recipes.cache.PathChildrenCache in project druid by druid-io.

the class Announcer method announce.

/**
   * Announces the provided bytes at the given path.  Announcement means that it will create an ephemeral node
   * and monitor it to make sure that it always exists until it is unannounced or this object is closed.
   *
   * @param path                  The path to announce at
   * @param bytes                 The payload to announce
   * @param removeParentIfCreated remove parent of "path" if we had created that parent
   */
public void announce(String path, byte[] bytes, boolean removeParentIfCreated) {
    synchronized (toAnnounce) {
        if (!started) {
            toAnnounce.add(new Announceable(path, bytes, removeParentIfCreated));
            return;
        }
    }
    final ZKPaths.PathAndNode pathAndNode = ZKPaths.getPathAndNode(path);
    final String parentPath = pathAndNode.getPath();
    boolean buildParentPath = false;
    ConcurrentMap<String, byte[]> subPaths = announcements.get(parentPath);
    if (subPaths == null) {
        try {
            if (curator.checkExists().forPath(parentPath) == null) {
                buildParentPath = true;
            }
        } catch (Exception e) {
            log.debug(e, "Problem checking if the parent existed, ignoring.");
        }
        // I don't have a watcher on this path yet, create a Map and start watching.
        announcements.putIfAbsent(parentPath, new MapMaker().<String, byte[]>makeMap());
        // Guaranteed to be non-null, but might be a map put in there by another thread.
        final ConcurrentMap<String, byte[]> finalSubPaths = announcements.get(parentPath);
        // Synchronize to make sure that I only create a listener once.
        synchronized (finalSubPaths) {
            if (!listeners.containsKey(parentPath)) {
                final PathChildrenCache cache = factory.make(curator, parentPath);
                cache.getListenable().addListener(new PathChildrenCacheListener() {

                    private final AtomicReference<Set<String>> pathsLost = new AtomicReference<Set<String>>(null);

                    @Override
                    public void childEvent(CuratorFramework client, PathChildrenCacheEvent event) throws Exception {
                        log.debug("Path[%s] got event[%s]", parentPath, event);
                        switch(event.getType()) {
                            case CHILD_REMOVED:
                                final ChildData child = event.getData();
                                final ZKPaths.PathAndNode childPath = ZKPaths.getPathAndNode(child.getPath());
                                final byte[] value = finalSubPaths.get(childPath.getNode());
                                if (value != null) {
                                    log.info("Node[%s] dropped, reinstating.", child.getPath());
                                    createAnnouncement(child.getPath(), value);
                                }
                                break;
                            case CONNECTION_LOST:
                                // Lost connection, which means session is broken, take inventory of what has been seen.
                                // This is to protect from a race condition in which the ephemeral node could have been
                                // created but not actually seen by the PathChildrenCache, which means that it won't know
                                // that it disappeared and thus will not generate a CHILD_REMOVED event for us.  Under normal
                                // circumstances, this can only happen upon connection loss; but technically if you have
                                // an adversary in the system, they could also delete the ephemeral node before the cache sees
                                // it.  This does not protect from that case, so don't have adversaries.
                                Set<String> pathsToReinstate = Sets.newHashSet();
                                for (String node : finalSubPaths.keySet()) {
                                    String path = ZKPaths.makePath(parentPath, node);
                                    log.info("Node[%s] is added to reinstate.", path);
                                    pathsToReinstate.add(path);
                                }
                                if (!pathsToReinstate.isEmpty() && !pathsLost.compareAndSet(null, pathsToReinstate)) {
                                    log.info("Already had a pathsLost set!?[%s]", parentPath);
                                }
                                break;
                            case CONNECTION_RECONNECTED:
                                final Set<String> thePathsLost = pathsLost.getAndSet(null);
                                if (thePathsLost != null) {
                                    for (String path : thePathsLost) {
                                        log.info("Reinstating [%s]", path);
                                        final ZKPaths.PathAndNode split = ZKPaths.getPathAndNode(path);
                                        createAnnouncement(path, announcements.get(split.getPath()).get(split.getNode()));
                                    }
                                }
                                break;
                        }
                    }
                });
                synchronized (toAnnounce) {
                    if (started) {
                        if (buildParentPath) {
                            createPath(parentPath, removeParentIfCreated);
                        }
                        startCache(cache);
                        listeners.put(parentPath, cache);
                    }
                }
            }
        }
        subPaths = finalSubPaths;
    }
    boolean created = false;
    synchronized (toAnnounce) {
        if (started) {
            byte[] oldBytes = subPaths.putIfAbsent(pathAndNode.getNode(), bytes);
            if (oldBytes == null) {
                created = true;
            } else if (!Arrays.equals(oldBytes, bytes)) {
                throw new IAE("Cannot reannounce different values under the same path");
            }
        }
    }
    if (created) {
        try {
            createAnnouncement(path, bytes);
        } catch (Exception e) {
            throw Throwables.propagate(e);
        }
    }
}

Example 45 with PathChildrenCache

use of org.apache.curator.framework.recipes.cache.PathChildrenCache in project BRFS by zhangnianli.

the class ZookeeperFileCoordinator method watchSink.

private void watchSink() throws Exception {
    sinkWatcher = new PathChildrenCache(client, ZKPaths.makePath(COORDINATOR_ROOT, COORDINATOR_SINK, selfService.getServiceId()), false);
    sinkWatcher.getListenable().addListener(new FileNodeListener());
    sinkWatcher.start();
}