Sanil15 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_r366608737
########## 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: WIll be exposed by external tool when some user needs to perform manual cleaning ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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