kaisun2000 commented on a change in pull request #789: Add FederatedZkClient
URL: https://github.com/apache/helix/pull/789#discussion_r384168154
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File path:
zookeeper-api/src/main/java/org/apache/helix/zookeeper/impl/client/FederatedZkClient.java
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@@ -20,344 +20,487 @@
*/
import java.util.List;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.TimeUnit;
+import org.apache.helix.msdcommon.datamodel.MetadataStoreRoutingData;
import org.apache.helix.zookeeper.api.client.RealmAwareZkClient;
+import org.apache.helix.zookeeper.impl.factory.DedicatedZkClientFactory;
import org.apache.helix.zookeeper.zkclient.DataUpdater;
import org.apache.helix.zookeeper.zkclient.IZkChildListener;
import org.apache.helix.zookeeper.zkclient.IZkDataListener;
+import org.apache.helix.zookeeper.zkclient.ZkConnection;
import org.apache.helix.zookeeper.zkclient.callback.ZkAsyncCallbacks;
-import org.apache.helix.zookeeper.zkclient.deprecated.IZkStateListener;
+import org.apache.helix.zookeeper.zkclient.IZkStateListener;
+import org.apache.helix.zookeeper.zkclient.serialize.BasicZkSerializer;
import org.apache.helix.zookeeper.zkclient.serialize.PathBasedZkSerializer;
import org.apache.helix.zookeeper.zkclient.serialize.ZkSerializer;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.Op;
import org.apache.zookeeper.OpResult;
+import org.apache.zookeeper.ZooDefs;
import org.apache.zookeeper.data.ACL;
import org.apache.zookeeper.data.Stat;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+
+/**
+ * Implements and supports all ZK operations defined in interface {@link
RealmAwareZkClient},
+ * except for session-aware operations such as creating ephemeral nodes, for
which
+ * an {@link UnsupportedOperationException} will be thrown.
+ * <p>
+ * It acts as a single ZK client but will automatically route
read/write/change subscription
+ * requests to the corresponding ZkClient with the help of metadata store
directory service.
+ * It could connect to multiple ZK addresses and maintain a {@link ZkClient}
for each ZK address.
+ */
+public class FederatedZkClient implements RealmAwareZkClient {
+ private static final Logger LOG =
LoggerFactory.getLogger(FederatedZkClient.class);
+ private static final String FEDERATED_ZK_CLIENT =
FederatedZkClient.class.getSimpleName();
+ private static final String DEDICATED_ZK_CLIENT_FACTORY =
+ DedicatedZkClientFactory.class.getSimpleName();
+
+ private final MetadataStoreRoutingData _metadataStoreRoutingData;
+ private final RealmAwareZkClient.RealmAwareZkClientConfig _clientConfig;
+
+ // ZK realm -> ZkClient
+ private final Map<String, ZkClient> _zkRealmToZkClientMap;
+
+ private volatile boolean _isClosed;
+ private PathBasedZkSerializer _pathBasedZkSerializer;
+
+ // TODO: support capacity of ZkClient number in one FederatedZkClient and do
garbage collection.
+ public FederatedZkClient(RealmAwareZkClient.RealmAwareZkClientConfig
clientConfig,
+ MetadataStoreRoutingData metadataStoreRoutingData) {
+ if (metadataStoreRoutingData == null) {
+ throw new IllegalArgumentException("MetadataStoreRoutingData cannot be
null!");
+ }
+ if (clientConfig == null) {
+ throw new IllegalArgumentException("Client config cannot be null!");
+ }
+
+ _isClosed = false;
+ _clientConfig = clientConfig;
+ _pathBasedZkSerializer = clientConfig.getZkSerializer();
+ _metadataStoreRoutingData = metadataStoreRoutingData;
+ _zkRealmToZkClientMap = new ConcurrentHashMap<>();
Review comment:
Nit, this can be done in the declaration place and make the
_zkRealmToZkClientMap final.
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