Examples with IZkDataListener org.apache.helix.zookeeper.zkclient.IZkDataListener used on opensource projects

Example 1 with IZkDataListener

use of org.apache.helix.zookeeper.zkclient.IZkDataListener in project ambry by linkedin.

the class HelixClusterManager method initializeHelixManagerAndPropertyStoreInLocalDC.

/**
 * Initialize HelixManager in local datacenter and complete subscription of HelixPropertyStore to listen for
 * PartitionOverride zNode. This needs to happen before other datacenters are initialized so that any partition
 * overrides can be properly honored.
 * @param dataCenterToZkAddress the map mapping each datacenter to its corresponding ZkAddress.
 * @param instanceName the String representation of the instance associated with this manager.
 * @param helixFactory the factory class to construct and get a reference to a {@link HelixManager}.
 * @return the HelixManager of local datacenter, or {@code null} if the local datacenter is
 *         {@link ReplicaType#CLOUD_BACKED}, as we currently do not support getting cluster state from Helix for cloud
 *         datacenters.
 * @throws Exception
 */
private HelixManager initializeHelixManagerAndPropertyStoreInLocalDC(Map<String, DcZkInfo> dataCenterToZkAddress, String instanceName, HelixFactory helixFactory) throws Exception {
    DcZkInfo dcZkInfo = dataCenterToZkAddress.get(clusterMapConfig.clusterMapDatacenterName);
    if (dcZkInfo.getReplicaType() == ReplicaType.CLOUD_BACKED) {
        return null;
    }
    // For now, the first ZK endpoint (if there are more than one endpoints) will be adopted by default. Note that, Ambry
    // doesn't support multiple HelixClusterManagers(spectators) on same node.
    String zkConnectStr = dcZkInfo.getZkConnectStrs().get(0);
    HelixManager manager = helixFactory.getZkHelixManagerAndConnect(clusterName, instanceName, InstanceType.SPECTATOR, zkConnectStr);
    helixPropertyStoreInLocalDc = manager.getHelixPropertyStore();
    logger.info("HelixPropertyStore from local datacenter {} is: {}", dcZkInfo.getDcName(), helixPropertyStoreInLocalDc);
    IZkDataListener dataListener = new IZkDataListener() {

        @Override
        public void handleDataChange(String dataPath, Object data) {
            logger.info("Received data change notification for: {}", dataPath);
        }

        @Override
        public void handleDataDeleted(String dataPath) {
            logger.info("Received data delete notification for: {}", dataPath);
        }
    };
    logger.info("Subscribing data listener to HelixPropertyStore.");
    helixPropertyStoreInLocalDc.subscribeDataChanges(PARTITION_OVERRIDE_ZNODE_PATH, dataListener);
    logger.info("Getting PartitionOverride ZNRecord from HelixPropertyStore");
    ZNRecord zNRecord = helixPropertyStoreInLocalDc.get(PARTITION_OVERRIDE_ZNODE_PATH, null, AccessOption.PERSISTENT);
    if (clusterMapConfig.clusterMapEnablePartitionOverride) {
        if (zNRecord != null) {
            partitionOverrideInfoMap.putAll(zNRecord.getMapFields());
            logger.info("partitionOverrideInfoMap is initialized!");
        } else {
            logger.warn("ZNRecord from HelixPropertyStore is NULL, the partitionOverrideInfoMap is empty.");
        }
    }
    return manager;
}