content: /*
   * 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.beam.sdk.loadtests;
  
  import static java.lang.String.format;
  
  import java.io.IOException;
  import java.util.Optional;
  import org.apache.beam.sdk.io.synthetic.SyntheticStep;
  import org.apache.beam.sdk.options.Default;
  import org.apache.beam.sdk.options.Description;
  import org.apache.beam.sdk.testutils.metrics.ByteMonitor;
  import org.apache.beam.sdk.transforms.DoFn;
  import org.apache.beam.sdk.transforms.GroupByKey;
  import org.apache.beam.sdk.transforms.ParDo;
  import org.apache.beam.sdk.values.KV;
  import org.apache.beam.sdk.values.PCollection;
  
  /**
   * Load test for {@link GroupByKey} operation.
   *
   * <p>The purpose of this test is to measure {@link GroupByKey}'s behaviour in stressful conditions.
   * It uses synthetic sources and {@link SyntheticStep} which both can be parametrized to generate
   * keys and values of various size, impose delay (sleep or cpu burnout) in various moments during
   * the pipeline execution and provide some other performance challenges.
   *
   * <p>In addition, this test allows to: - fanout: produce one input (using Synthetic Source) and
   * process it with multiple sessions performing the same set of operations - reiterate produced
   * PCollection multiple times
   *
   * <p>To run it manually, use the following command:
   *
   * <pre>
   *    ./gradlew :sdks:java:testing:load-tests:run -PloadTest.args='
   *      --fanout=1
   *      --iterations=1
   *      --sourceOptions={"numRecords":1000,...}
   *      --stepOptions={"outputRecordsPerInputRecord":2...}'
   *      -PloadTest.mainClass="org.apache.beam.sdk.loadtests.GroupByKeyLoadTest"
   * </pre>
   */
  public class GroupByKeyLoadTest extends LoadTest<GroupByKeyLoadTest.Options> {
  
    private static final String METRICS_NAMESPACE = "gbk";
  
    /** Pipeline options for the test. */
    public interface Options extends LoadTestOptions {
  
      @Description("The number of GroupByKey operations to perform in parallel (fanout)")
      @Default.Integer(1)
      Integer getFanout();
  
      void setFanout(Integer fanout);
  
      @Description("Number of reiterations over per-key-grouped values to perform.")
      @Default.Integer(1)
      Integer getIterations();
  
      void setIterations(Integer iterations);
    }
  
    private GroupByKeyLoadTest(String[] args) throws IOException {
      super(args, Options.class, METRICS_NAMESPACE);
    }
  
    @Override
    void loadTest() throws IOException {
      Optional<SyntheticStep> syntheticStep = createStep(options.getStepOptions());
  
      PCollection<KV<byte[], byte[]>> input =
          pipeline
              .apply("Read input", readFromSource(sourceOptions))
              .apply("Collect start time metrics", ParDo.of(runtimeMonitor))
              .apply(
                  "Total bytes monitor",
                  ParDo.of(new ByteMonitor(METRICS_NAMESPACE, "totalBytes.count")));
  
      input = applyWindowing(input);
  
      for (int branch = 0; branch < options.getFanout(); branch++) {
        applyStepIfPresent(input, format("Synthetic step (%s)", branch), syntheticStep)
            .apply(format("Group by key (%s)", branch), GroupByKey.create())
            .apply(
                format("Ungroup and reiterate (%s)", branch),
                ParDo.of(new UngroupAndReiterate(options.getIterations())))
            .apply(format("Collect end time metrics (%s)", branch), ParDo.of(runtimeMonitor));
      }
    }
  
    private static class UngroupAndReiterate
        extends DoFn<KV<byte[], Iterable<byte[]>>, KV<byte[], byte[]>> {
  
      private int iterations;
  
      UngroupAndReiterate(int iterations) {
        this.iterations = iterations;
      }
  
      @ProcessElement
      public void processElement(ProcessContext c) {
        byte[] key = c.element().getKey();
  
        // reiterate "iterations" times, emit output only once
        for (int i = 0; i < iterations; i++) {
          for (byte[] value : c.element().getValue()) {
  
            if (i == iterations - 1) {
              c.output(KV.of(key, value));
            }
          }
        }
      }
    }
  
    public static void main(String[] args) throws IOException {
      new GroupByKeyLoadTest(args).run();
    }
  }
  