rmatharu commented on a change in pull request #1227: SAMZA-2404: [SEP-22] 
Container Placement Handler for dispatching container placement messages 
between metastore and JobCoordinator
URL: https://github.com/apache/samza/pull/1227#discussion_r366510342
 
 

 ##########
 File path: 
samza-core/src/main/java/org/apache/samza/clustermanager/container/placement/ContainerPlacementUtil.java
 ##########
 @@ -0,0 +1,273 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.samza.clustermanager.container.placement;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Preconditions;
+import java.io.IOException;
+import java.time.Duration;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import java.util.UUID;
+import org.apache.commons.lang3.ArrayUtils;
+import org.apache.samza.SamzaException;
+import org.apache.samza.container.placement.ContainerPlacementMessage;
+import org.apache.samza.container.placement.ContainerPlacementRequestMessage;
+import org.apache.samza.container.placement.ContainerPlacementResponseMessage;
+import 
org.apache.samza.coordinator.metadatastore.NamespaceAwareCoordinatorStreamStore;
+import org.apache.samza.metadatastore.MetadataStore;
+import org.codehaus.jackson.map.ObjectMapper;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Entity managing read writes to the metastore for {@link 
org.apache.samza.container.placement.ContainerPlacementRequestMessage}
+ * and {@link 
org.apache.samza.container.placement.ContainerPlacementResponseMessage}
+ *
+ * ContainerPlacement control messages are written to {@link MetadataStore} as 
a KV under the namespace CONTAINER_PLACEMENT_STORE_NAMESPACE
+ * Key is combination of {@link UUID} and message type (either {@link 
ContainerPlacementRequestMessage} or {@link ContainerPlacementResponseMessage})
+ * and the value is the actual request or response message
+ */
+public class ContainerPlacementUtil {
+
+  private static final Logger LOG = 
LoggerFactory.getLogger(ContainerPlacementUtil.class);
+
+  private static final Integer VERSION = 1;
+  public static final String CONTAINER_PLACEMENT_STORE_NAMESPACE = 
"samza-place-container-v" + VERSION;
+
+  private final NamespaceAwareCoordinatorStreamStore 
containerPlacementMessageStore;
+  private final ObjectMapper objectMapper = 
ContainerPlacementMessageObjectMapper.getObjectMapper();
+
+  private boolean stopped = true;
+
+  public ContainerPlacementUtil(MetadataStore containerPlacementMessageStore) {
+    Preconditions.checkNotNull(containerPlacementMessageStore, "MetadataStore 
cannot be null");
+    this.containerPlacementMessageStore =
+        new 
NamespaceAwareCoordinatorStreamStore(containerPlacementMessageStore, 
CONTAINER_PLACEMENT_STORE_NAMESPACE);
+  }
+
+  /**
+   * Perform startup operations. Method is idempotent.
+   */
+  public void start() {
+    if (stopped) {
+      LOG.info("Starting ContainerPlacementStore");
+      containerPlacementMessageStore.init();
+      stopped = false;
+    } else {
+      LOG.warn("already started");
+    }
+  }
+
+  /**
+   * Perform teardown operations. Method is idempotent.
+   */
+  public void stop() {
+    if (!stopped) {
+      LOG.info("stopping");
+      containerPlacementMessageStore.close();
+      stopped = true;
+    } else {
+      LOG.warn("already stopped");
+    }
+  }
+
+  /**
+   * Checks if ContainerPlacementUtil is running
+   */
+  public boolean isRunning() {
+    return !stopped;
+  }
+
+  /**
+   * Writes a {@link ContainerPlacementRequestMessage} to the underlying 
metastore. This method should be used by external controllers
+   * to issue a request to JobCoordinator
+   *
+   * @param deploymentId identifier of the deployment
+   * @param processorId logical id of the samza container 0,1,2
+   * @param destinationHost host where the container is desired to move
+   * @param requestExpiry optional per request expiry timeout for requests to 
cluster manager
+   * @param timestamp timestamp of the request
+   * @return uuid generated for the request
+   */
+  public UUID writeContainerPlacementRequestMessage(String deploymentId, 
String processorId, String destinationHost,
+      Duration requestExpiry, long timestamp) {
+    Preconditions.checkState(!stopped, "Underlying metadata store not 
available");
+    Preconditions.checkNotNull(deploymentId, "deploymentId should not be 
null");
+    Preconditions.checkNotNull(processorId, "processorId not be null");
+    Preconditions.checkNotNull(destinationHost, "destinationHost should not be 
null");
+    Preconditions.checkNotNull(timestamp, "timestamp should not be null");
+    UUID uuid = UUID.randomUUID();
+    ContainerPlacementRequestMessage message =
+        new ContainerPlacementRequestMessage(uuid, deploymentId, processorId, 
destinationHost, requestExpiry,
+            timestamp);
+    try {
+      
containerPlacementMessageStore.put(toContainerPlacementMessageKey(message.getUuid(),
 message.getClass()),
+          objectMapper.writeValueAsBytes(message));
+    } catch (Exception ex) {
+      throw new SamzaException(
+          String.format("ContainerPlacementRequestMessage might have been not 
written to metastore %s", message), ex);
+    }
+    return uuid;
+  }
+
+  /**
+   * Writes a {@link ContainerPlacementResponseMessage} to the underlying 
metastore. This method should be used by Job Coordinator
+   * only to write responses to Container Placement Action
+   * @param message
+   */
+  void 
writeContainerPlacementResponseMessage(ContainerPlacementResponseMessage 
message) {
+    Preconditions.checkState(!stopped, "Underlying metadata store not 
available");
+    Preconditions.checkNotNull(message);
+    try {
+      
containerPlacementMessageStore.put(toContainerPlacementMessageKey(message.getUuid(),
 message.getClass()),
+          objectMapper.writeValueAsBytes(message));
+    } catch (Exception ex) {
+      throw new SamzaException(
+          String.format("ContainerPlacementResponseMessage might have been not 
written to metastore %s", message), ex);
+    }
+  }
+
+  /**
+   * Reads a {@link ContainerPlacementRequestMessage} from the underlying 
metastore
+   * @param uuid uuid of the request
+   * @return ContainerPlacementRequestMessage if present
+   */
+  public Optional<ContainerPlacementRequestMessage> 
readContainerPlacementRequestMessage(UUID uuid) {
+    Preconditions.checkState(!stopped, "Underlying metadata store not 
available");
+    Preconditions.checkNotNull(uuid, "uuid cannot be null");
+
+    byte[] messageBytes = containerPlacementMessageStore.get(
+        toContainerPlacementMessageKey(uuid, 
ContainerPlacementRequestMessage.class));
+    if (ArrayUtils.isNotEmpty(messageBytes)) {
+      try {
+        ContainerPlacementRequestMessage requestMessage =
+            (ContainerPlacementRequestMessage) 
objectMapper.readValue(messageBytes, ContainerPlacementMessage.class);
+        return Optional.of(requestMessage);
+      } catch (IOException e) {
+        throw new SamzaException(
+            String.format("Error reading the ContainerPlacementResponseMessage 
for uuid {}", uuid), e);
+      }
+    }
+    return Optional.empty();
+  }
+
+  /**
+   * Reads a {@link ContainerPlacementResponseMessage} from the underlying 
metastore
+   * @param uuid uuid of the response message
+   * @return ContainerPlacementResponseMessage if present
+   */
+  public Optional<ContainerPlacementResponseMessage> 
readContainerPlacementResponseMessage(UUID uuid) {
+    Preconditions.checkState(!stopped, "Underlying metadata store not 
available");
+    Preconditions.checkNotNull(uuid, "uuid cannot be null");
+
+    byte[] messageBytes = containerPlacementMessageStore.get(
+        toContainerPlacementMessageKey(uuid, 
ContainerPlacementResponseMessage.class));
+    if (ArrayUtils.isNotEmpty(messageBytes)) {
+      try {
+        ContainerPlacementResponseMessage requestMessage =
+            (ContainerPlacementResponseMessage) 
objectMapper.readValue(messageBytes, ContainerPlacementMessage.class);
+        return Optional.of(requestMessage);
+      } catch (IOException e) {
+        throw new SamzaException(
+            String.format("Error reading the ContainerPlacementResponseMessage 
for uuid {}", uuid), e);
+      }
+    }
+    return Optional.empty();
+  }
+
+  /**
+   * Deletes a {@link ContainerPlacementRequestMessage} if present identified 
by the key {@code uuid}
+   * @param uuid uuid of the request
+   */
+  public void deleteContainerPlacementRequestMessage(UUID uuid) {
+    Preconditions.checkState(!stopped, "Underlying metadata store not 
available");
+    Preconditions.checkNotNull(uuid, "uuid cannot be null");
+    containerPlacementMessageStore.delete(toContainerPlacementMessageKey(uuid, 
ContainerPlacementRequestMessage.class));
+  }
+
+  /**
+   * Deletes a {@link ContainerPlacementResponseMessage} if present identified 
by the key {@code processorId}
+   * @param uuid uuid of the request
+   */
+  public void deleteContainerPlacementResponseMessage(UUID uuid) {
+    Preconditions.checkState(!stopped, "Underlying metadata store not 
available");
+    Preconditions.checkNotNull(uuid, "uuid cannot be null");
+    containerPlacementMessageStore.delete(toContainerPlacementMessageKey(uuid, 
ContainerPlacementResponseMessage.class));
+  }
+
+  /**
+   * Deletes both {@link ContainerPlacementRequestMessage} and {@link 
ContainerPlacementResponseMessage} identified by
+   * uuid
+   * @param uuid uuid of request and response message
+   */
+  public void deleteAllContainerPlacementMessages(UUID uuid) {
+    deleteContainerPlacementRequestMessage(uuid);
+    deleteContainerPlacementResponseMessage(uuid);
+  }
+
+  /**
+   * Deletes all {@link ContainerPlacementMessage}
+   */
+  public void deleteAllContainerPlacementMessages() {
 
 Review comment:
   This method is not invoked from anywhere, then why do we need it?

----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
 
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org


With regards,
Apache Git Services

Reply via email to