vjagadish1989 commented on a change in pull request #938: SAMZA-1531: Support run.id in standalone for batch processing. URL: https://github.com/apache/samza/pull/938#discussion_r286714672
########## File path: samza-core/src/main/java/org/apache/samza/coordinator/RunIdGenerator.java ########## @@ -0,0 +1,110 @@ +/* + * 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.coordinator; + +import com.google.common.base.Preconditions; +import java.io.UnsupportedEncodingException; +import java.time.Duration; +import java.util.Optional; +import java.util.UUID; +import org.apache.samza.SamzaException; +import org.apache.samza.metadatastore.MetadataStore; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + + +/** + * Generates RunId for Standalone use case + * If there is only one processor in the quorum (registered with ClusterMembership) then create new runid and add to store + * Else read runid from the store + * + * Steps to generate: + * 1. acquire lock + * 2. add self to quorum (register itself with ClusterMembership) + * 3. get number of processors in quorum + * 4. if qurorum size is 1 (only self) then create new runid and write to store + * 5. if quorum size if greater than 1 then read runid from store + * 6. unlock + */ +public class RunIdGenerator { + private static final Logger LOG = LoggerFactory.getLogger(RunIdGenerator.class); + + private final CoordinationUtils coordinationUtils; + private final MetadataStore metadataStore; + private final ClusterMembership clusterMembership; + private String processorId = null; + private volatile boolean closed = false; + + public RunIdGenerator(CoordinationUtils coordinationUtils, MetadataStore metadataStore) { + Preconditions.checkNotNull(coordinationUtils, "CoordinationUtils cannot be null"); + Preconditions.checkNotNull(metadataStore, "MetadataStore cannot be null"); + this.coordinationUtils = coordinationUtils; + this.metadataStore = metadataStore; + this.clusterMembership = coordinationUtils.getClusterMembership(); + Preconditions.checkNotNull(this.clusterMembership, "Failed to create utils for run id generation"); + } + + public Optional<String> getRunId() { + DistributedLock runIdLock; + String runId = null; + + runIdLock = coordinationUtils.getLock(CoordinationConstants.RUNID_LOCK_ID); + if (runIdLock == null) { + throw new SamzaException("Failed to create utils for run id generation"); + } + + try { + // acquire lock to write or read run.id + if (runIdLock.lock(Duration.ofMillis(CoordinationConstants.LOCK_TIMEOUT_MS))) { + LOG.info("lock acquired for run.id generation by this processor"); + processorId = clusterMembership.registerProcessor(); + int numberOfActiveProcessors = clusterMembership.getNumberOfProcessors(); + if (numberOfActiveProcessors == 0) { + String msg = String.format("Processor failed to fetch number of processors for run.id generation"); + throw new SamzaException(msg); + } + if (numberOfActiveProcessors == 1) { + runId = + String.valueOf(System.currentTimeMillis()) + "-" + UUID.randomUUID().toString().substring(0, 8); + LOG.info("Writing the run id for this run as {}", runId); + metadataStore.put(CoordinationConstants.RUNID_STORE_KEY, runId.getBytes("UTF-8")); + } else { + runId = new String(metadataStore.get(CoordinationConstants.RUNID_STORE_KEY)); + LOG.info("Read the run id for this run as {}", runId); + } + runIdLock.unlock(); + } else { + throw new SamzaException("Processor timed out waiting to acquire lock for run.id generation"); + } + } catch (UnsupportedEncodingException e) { + throw new SamzaException("Processor could not serialize/deserialize string for run.id generation", e); + } + return Optional.ofNullable(runId); Review comment: Can you either return a runId or throw a SamzaException if you can't generate run-id? would be nice to not use optionals ---------------------------------------------------------------- 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: [email protected] With regards, Apache Git Services
