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

Example 36 with Watcher

use of org.apache.zookeeper.Watcher in project lucene-solr by apache.

the class ZkStateReader method createClusterStateWatchersAndUpdate.

public synchronized void createClusterStateWatchersAndUpdate() throws KeeperException, InterruptedException {
    // We need to fetch the current cluster state and the set of live nodes
    LOG.debug("Updating cluster state from ZooKeeper... ");
    // Sanity check ZK structure.
    if (!zkClient.exists(CLUSTER_STATE, true)) {
        throw new SolrException(ErrorCode.SERVICE_UNAVAILABLE, "Cannot connect to cluster at " + zkClient.getZkServerAddress() + ": cluster not found/not ready");
    }
    // on reconnect of SolrZkClient force refresh and re-add watches.
    loadClusterProperties();
    refreshLiveNodes(new LiveNodeWatcher());
    refreshLegacyClusterState(new LegacyClusterStateWatcher());
    refreshStateFormat2Collections();
    refreshCollectionList(new CollectionsChildWatcher());
    synchronized (ZkStateReader.this.getUpdateLock()) {
        constructState(Collections.emptySet());
        zkClient.exists(ALIASES, new Watcher() {

            @Override
            public void process(WatchedEvent event) {
                // session events are not change events, and do not remove the watcher
                if (EventType.None.equals(event.getType())) {
                    return;
                }
                try {
                    synchronized (ZkStateReader.this.getUpdateLock()) {
                        LOG.debug("Updating aliases... ");
                        // remake watch
                        final Watcher thisWatch = this;
                        final Stat stat = new Stat();
                        final byte[] data = zkClient.getData(ALIASES, thisWatch, stat, true);
                        ZkStateReader.this.aliases = ClusterState.load(data);
                        LOG.debug("New alias definition is: " + ZkStateReader.this.aliases.toString());
                    }
                } catch (KeeperException.ConnectionLossException | KeeperException.SessionExpiredException e) {
                    LOG.warn("ZooKeeper watch triggered, but Solr cannot talk to ZK: [{}]", e.getMessage());
                } catch (KeeperException e) {
                    LOG.error("A ZK error has occurred", e);
                    throw new ZooKeeperException(SolrException.ErrorCode.SERVER_ERROR, "A ZK error has occurred", e);
                } catch (InterruptedException e) {
                    // Restore the interrupted status
                    Thread.currentThread().interrupt();
                    LOG.warn("Interrupted", e);
                }
            }
        }, true);
    }
    updateAliases();
    if (securityNodeListener != null) {
        addSecuritynodeWatcher(pair -> {
            ConfigData cd = new ConfigData();
            cd.data = pair.first() == null || pair.first().length == 0 ? EMPTY_MAP : Utils.getDeepCopy((Map) fromJSON(pair.first()), 4, false);
            cd.version = pair.second() == null ? -1 : pair.second().getVersion();
            securityData = cd;
            securityNodeListener.run();
        });
        securityData = getSecurityProps(true);
    }
}

Example 37 with Watcher

use of org.apache.zookeeper.Watcher in project lucene-solr by apache.

the class ZkStateReader method addSecuritynodeWatcher.

private void addSecuritynodeWatcher(final Callable<Pair<byte[], Stat>> callback) throws KeeperException, InterruptedException {
    zkClient.exists(SOLR_SECURITY_CONF_PATH, new Watcher() {

        @Override
        public void process(WatchedEvent event) {
            // session events are not change events, and do not remove the watcher
            if (EventType.None.equals(event.getType())) {
                return;
            }
            try {
                synchronized (ZkStateReader.this.getUpdateLock()) {
                    LOG.debug("Updating [{}] ... ", SOLR_SECURITY_CONF_PATH);
                    // remake watch
                    final Watcher thisWatch = this;
                    final Stat stat = new Stat();
                    final byte[] data = getZkClient().getData(SOLR_SECURITY_CONF_PATH, thisWatch, stat, true);
                    try {
                        callback.call(new Pair<>(data, stat));
                    } catch (Exception e) {
                        LOG.error("Error running collections node listener", e);
                    }
                }
            } catch (KeeperException.ConnectionLossException | KeeperException.SessionExpiredException e) {
                LOG.warn("ZooKeeper watch triggered, but Solr cannot talk to ZK: [{}]", e.getMessage());
            } catch (KeeperException e) {
                LOG.error("A ZK error has occurred", e);
                throw new ZooKeeperException(ErrorCode.SERVER_ERROR, "", e);
            } catch (InterruptedException e) {
                // Restore the interrupted status
                Thread.currentThread().interrupt();
                LOG.warn("Interrupted", e);
            }
        }
    }, true);
}

Example 38 with Watcher

use of org.apache.zookeeper.Watcher in project lucene-solr by apache.

the class ZkStateReader method waitForState.

/**
   * Block until a CollectionStatePredicate returns true, or the wait times out
   *
   * Note that the predicate may be called again even after it has returned true, so
   * implementors should avoid changing state within the predicate call itself.
   *
   * @param collection the collection to watch
   * @param wait       how long to wait
   * @param unit       the units of the wait parameter
   * @param predicate  the predicate to call on state changes
   * @throws InterruptedException on interrupt
   * @throws TimeoutException on timeout
   */
public void waitForState(final String collection, long wait, TimeUnit unit, CollectionStatePredicate predicate) throws InterruptedException, TimeoutException {
    final CountDownLatch latch = new CountDownLatch(1);
    CollectionStateWatcher watcher = (n, c) -> {
        boolean matches = predicate.matches(n, c);
        if (matches)
            latch.countDown();
        return matches;
    };
    registerCollectionStateWatcher(collection, watcher);
    try {
        // wait for the watcher predicate to return true, or time out
        if (!latch.await(wait, unit))
            throw new TimeoutException();
    } finally {
        removeCollectionStateWatcher(collection, watcher);
    }
}

Example 39 with Watcher

use of org.apache.zookeeper.Watcher in project cdap by caskdata.

the class ResourceCoordinatorClient method watchAssignment.

/**
   * Starts watching ZK for ResourceAssignment changes for the given service.
   */
private void watchAssignment(final String serviceName) {
    final String zkPath = CoordinationConstants.ASSIGNMENTS_PATH + "/" + serviceName;
    // Watch for both getData() and exists() call
    Watcher watcher = wrapWatcher(new AssignmentWatcher(serviceName, EnumSet.of(Watcher.Event.EventType.NodeDataChanged, Watcher.Event.EventType.NodeDeleted)));
    Futures.addCallback(zkClient.getData(zkPath, watcher), wrapCallback(new FutureCallback<NodeData>() {

        @Override
        public void onSuccess(NodeData result) {
            try {
                ResourceAssignment assignment = CoordinationConstants.RESOURCE_ASSIGNMENT_CODEC.decode(result.getData());
                LOG.debug("Received resource assignment for {}. {}", serviceName, assignment.getAssignments());
                handleAssignmentChange(serviceName, assignment);
            } catch (Exception e) {
                LOG.error("Failed to decode ResourceAssignment {}", Bytes.toStringBinary(result.getData()), e);
            }
        }

        @Override
        public void onFailure(Throwable t) {
            if (t instanceof KeeperException.NoNodeException) {
                // Treat it as assignment has been removed. If the node doesn't exists for the first time fetch data,
                // there will be no oldAssignment, hence the following call would be a no-op.
                handleAssignmentChange(serviceName, new ResourceAssignment(serviceName));
                // Watch for exists if it still interested
                synchronized (ResourceCoordinatorClient.this) {
                    if (changeListeners.containsKey(serviceName)) {
                        watchAssignmentOnExists(serviceName);
                    }
                }
            } else {
                LOG.error("Failed to getData on ZK {}{}", zkClient.getConnectString(), zkPath, t);
                doNotifyFailed(t);
            }
        }
    }), Threads.SAME_THREAD_EXECUTOR);
}

Example 40 with Watcher

use of org.apache.zookeeper.Watcher in project zookeeper by apache.

the class InstanceContainer method processResult.

@Override
public void processResult(int rc, String path, Object ctx, List<String> children) {
    if (rc != KeeperException.Code.OK.intValue()) {
        // try it again
        zk.getChildren(assignmentsNode, true, this, null);
        return;
    }
    Map<String, Instance> newList = new HashMap<String, Instance>();
    // check for differences
    Stat stat = new Stat();
    for (String child : children) {
        Instance i = instances.remove(child);
        if (i == null) {
            // Start up a new instance
            byte[] data = null;
            String myNode = assignmentsNode + '/' + child;
            while (true) {
                try {
                    data = zk.getData(myNode, true, stat);
                    break;
                } catch (NoNodeException e) {
                    // The node doesn't exist anymore, so skip it
                    break;
                } catch (KeeperException e) {
                    e.printStackTrace();
                } catch (InterruptedException e) {
                    return;
                }
            }
            if (data != null) {
                String instanceSpec = new String(data);
                int spaceIndex = instanceSpec.indexOf(' ');
                String clazz;
                String conf;
                if (spaceIndex == -1) {
                    clazz = instanceSpec;
                    conf = null;
                } else {
                    clazz = instanceSpec.substring(0, spaceIndex);
                    conf = instanceSpec.substring(spaceIndex + 1);
                }
                try {
                    Class<?> c = Class.forName(clazz);
                    i = (Instance) c.newInstance();
                    Reporter reporter = new MyReporter(child);
                    i.setReporter(reporter);
                    i.configure(conf);
                    i.start();
                    newList.put(child, i);
                    int ver = stat.getVersion();
                    Instance myInstance = i;
                    DataCallback dc = new MyDataCallback(myNode, myInstance, ver);
                    Watcher watcher = new MyWatcher(myNode, dc);
                    zk.getData(myNode, watcher, dc, watcher);
                } catch (Exception e) {
                    LOG.warn("Skipping " + child, e);
                    if (e.getCause() != null) {
                        LOG.warn("Caused by", e.getCause());
                    }
                }
            }
        } else {
            // just move it to the new list
            newList.put(child, i);
        }
    }
    // kill anything that was removed for the children
    for (Map.Entry<String, Instance> i : instances.entrySet()) {
        i.getValue().stop();
        try {
            rmnod(reportsNode + '/' + i.getKey());
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
        } catch (KeeperException e) {
            e.printStackTrace();
        }
    }
    instances = newList;
}