narendly commented on a change in pull request #796: WIP: Add
SharedZkClient/InnerSharedZkClient implementation
URL: https://github.com/apache/helix/pull/796#discussion_r382935050
##########
File path:
zookeeper-api/src/main/java/org/apache/helix/zookeeper/impl/client/SharedZkClient.java
##########
@@ -37,79 +51,549 @@
* HelixZkClient that uses shared ZkConnection.
* A SharedZkClient won't manipulate the shared ZkConnection directly.
*/
-public class SharedZkClient extends ZkClient implements HelixZkClient {
+public class SharedZkClient implements RealmAwareZkClient {
private static Logger LOG = LoggerFactory.getLogger(SharedZkClient.class);
- /*
- * Since we cannot really disconnect the ZkConnection, we need a dummy
ZkConnection placeholder.
- * This is to ensure connection field is never null even the shared
RealmAwareZkClient instance is closed so as to avoid NPE.
- */
- private final static ZkConnection IDLE_CONNECTION = new
ZkConnection("Dummy_ZkServers");
- private final OnCloseCallback _onCloseCallback;
- private final ZkConnectionManager _connectionManager;
-
- public interface OnCloseCallback {
- /**
- * Triggered after the RealmAwareZkClient is closed.
- */
- void onClose();
- }
-
- /**
- * Construct a shared RealmAwareZkClient that uses a shared ZkConnection.
- *
- * @param connectionManager The manager of the shared ZkConnection.
- * @param clientConfig ZkClientConfig details to create the shared
RealmAwareZkClient.
- * @param callback Clean up logic when the shared
RealmAwareZkClient is closed.
- */
- public SharedZkClient(ZkConnectionManager connectionManager, ZkClientConfig
clientConfig,
- OnCloseCallback callback) {
- super(connectionManager.getConnection(), 0,
clientConfig.getOperationRetryTimeout(),
- clientConfig.getZkSerializer(), clientConfig.getMonitorType(),
clientConfig.getMonitorKey(),
- clientConfig.getMonitorInstanceName(),
clientConfig.isMonitorRootPathOnly());
- _connectionManager = connectionManager;
- // Register to the base dedicated RealmAwareZkClient
- _connectionManager.registerWatcher(this);
- _onCloseCallback = callback;
+
+ private final HelixZkClient _innerSharedZkClient;
+ private final String _zkRealmShardingKey;
+
+ public SharedZkClient(RealmAwareZkClient.RealmAwareZkConnectionConfig
connectionConfig,
+ RealmAwareZkClient.RealmAwareZkClientConfig clientConfig,
+ MetadataStoreRoutingData metadataStoreRoutingData) {
+
+ if (connectionConfig == null) {
+ throw new IllegalArgumentException("RealmAwareZkConnectionConfig cannot
be null!");
+ }
+ _zkRealmShardingKey = connectionConfig.getZkRealmShardingKey();
+
+ // TODO: use _zkRealmShardingKey to generate zkRealmAddress. This can done
the same way of pull 765 once @hunter check it in.
+ // Get the ZkRealm address based on the ZK path sharding key
+ String zkRealmAddress = null;
+ zkRealmAddress =
metadataStoreRoutingData.getMetadataStoreRealm(_zkRealmShardingKey);
+
+ // Create an InnerSharedZkClient to actually serve ZK requests
+ // TODO: Rename HelixZkClient in the future or remove it entirely - this
will be a backward-compatibility breaking change because HelixZkClient is being
used by Helix users.
+
+ // Note, here delegate _innerSharedZkClient would share the same
connectionManager. Once the close() API of
+ // SharedZkClient is invoked, we can just call the close() API of delegate
_innerSharedZkClient. This would follow
+ // exactly the pattern of innerSharedZkClient closing logic, which would
close the connectionManager when the last
+ // sharedInnerZkClient is closed.
+ HelixZkClient.ZkConnectionConfig zkConnectionConfig =
+ new HelixZkClient.ZkConnectionConfig(zkRealmAddress)
+ .setSessionTimeout(connectionConfig.getSessionTimeout());
+ HelixZkClient.ZkClientConfig zkClientConfig = new
HelixZkClient.ZkClientConfig();
+ zkClientConfig.setZkSerializer(clientConfig.getZkSerializer())
+ .setConnectInitTimeout(clientConfig.getConnectInitTimeout())
+ .setOperationRetryTimeout(clientConfig.getOperationRetryTimeout())
+ .setMonitorInstanceName(clientConfig.getMonitorInstanceName())
+ .setMonitorKey(clientConfig.getMonitorKey())
+ .setMonitorType(clientConfig.getMonitorType())
+ .setMonitorRootPathOnly(clientConfig.isMonitorRootPathOnly());
+ _innerSharedZkClient = SharedZkClientFactory.getInstance()
+ .buildZkClient(zkConnectionConfig, zkClientConfig);
}
@Override
- public void close() {
- super.close();
- if (isClosed()) {
- // Note that if register is not done while constructing, these private
fields may not be init yet.
- if (_connectionManager != null) {
- _connectionManager.unregisterWatcher(this);
+ public List<String> subscribeChildChanges(String path, IZkChildListener
listener) {
+ if (!checkIfPathBelongsToZkRealm(path)) {
+ throw new IllegalArgumentException(
+ "The given path does not map to the ZK realm for this
DedicatedZkClient! Path: " + path
+ + " ZK realm sharding key: " + _zkRealmShardingKey);
+ }
+ return _innerSharedZkClient.subscribeChildChanges(path, listener);
+ }
+
+ @Override
+ public void unsubscribeChildChanges(String path, IZkChildListener listener) {
+ if (!checkIfPathBelongsToZkRealm(path)) {
+ throw new IllegalArgumentException(
+ "The given path does not map to the ZK realm for this
DedicatedZkClient! Path: " + path
+ + " ZK realm sharding key: " + _zkRealmShardingKey);
+ }
Review comment:
Please review my comment above on making the check simpler and apply them to
all methods overriden in SharedZkClient. Thanks :)
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