runners/flink/src/main/java/org/apache/beam/runners/flink/translation/functions/FlinkExecutableStageContextFactory.java

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 * distributed with this work for additional information
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 * 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
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package org.apache.beam.runners.flink.translation.functions;

import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import org.apache.beam.runners.core.construction.PipelineOptionsTranslation;
import org.apache.beam.runners.fnexecution.control.DefaultExecutableStageContext.MultiInstanceFactory;
import org.apache.beam.runners.fnexecution.control.ExecutableStageContext;
import org.apache.beam.runners.fnexecution.provisioning.JobInfo;
import org.apache.beam.sdk.options.PortablePipelineOptions;
import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.MoreObjects;
import org.apache.flink.api.java.ExecutionEnvironment;

/** Singleton class that contains one {@link MultiInstanceFactory} per job. */
public class FlinkExecutableStageContextFactory implements ExecutableStageContext.Factory {

  private static final FlinkExecutableStageContextFactory instance =
      new FlinkExecutableStageContextFactory();
  // This map should only ever have a single element, as each job will have its own
  // classloader and therefore its own instance of FlinkExecutableStageContextFactory. This
  // code supports multiple JobInfos in order to provide a sensible implementation of
  // Factory.get(JobInfo), which in theory could be called with different JobInfos.
  private static final ConcurrentMap<String, MultiInstanceFactory> jobFactories =
      new ConcurrentHashMap<>();

  private FlinkExecutableStageContextFactory() {}

  public static FlinkExecutableStageContextFactory getInstance() {
    return instance;
  }

  @Override
  public ExecutableStageContext get(JobInfo jobInfo) {
    MultiInstanceFactory jobFactory =
        jobFactories.computeIfAbsent(
            jobInfo.jobId(),
            k -> {
              PortablePipelineOptions portableOptions =
                  PipelineOptionsTranslation.fromProto(jobInfo.pipelineOptions())
                      .as(PortablePipelineOptions.class);

              return new MultiInstanceFactory(
                  MoreObjects.firstNonNull(portableOptions.getSdkWorkerParallelism(), 1L)
                      .intValue(),
                  // Clean up context immediately if its class is not loaded on Flink parent
                  // classloader.
                  (caller) ->
                      caller.getClass().getClassLoader()
                          != ExecutionEnvironment.class.getClassLoader());
            });

    return jobFactory.get(jobInfo);
  }
}