StateWatcher watches and reports changed Pipeline State

runners/prism/java/build.gradle

@@ -26,11 +26,13 @@ description = "Apache Beam :: Runners :: Prism :: Java"
 ext.summary = "Support for executing a pipeline on Prism."
 
 dependencies {
+    implementation project(path: ":model:job-management", configuration: "shadow")
     implementation project(path: ":sdks:java:core", configuration: "shadow")
     implementation project(":runners:portability:java")
 
     implementation library.java.joda_time
     implementation library.java.slf4j_api
+    implementation library.java.vendored_grpc_1_60_1
     implementation library.java.vendored_guava_32_1_2_jre
 
     testImplementation library.java.junit

runners/prism/java/src/main/java/org/apache/beam/runners/prism/StateListener.java

@@ -0,0 +1,27 @@
+/*
+ * 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.runners.prism;
+
+import org.apache.beam.sdk.PipelineResult;
+
+/** Listens for {@link PipelineResult.State} changes reported by the {@link StateWatcher}. */
+interface StateListener {
+
+  /** Callback invoked when {@link StateWatcher} discovers a {@link PipelineResult.State} change. */
+  void onStateChanged(PipelineResult.State state);
+}

runners/prism/java/src/main/java/org/apache/beam/runners/prism/StateWatcher.java

@@ -0,0 +1,146 @@
+/*
+ * 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.runners.prism;
+
+import com.google.auto.value.AutoValue;
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Optional;
+import java.util.concurrent.TimeUnit;
+import org.apache.beam.model.jobmanagement.v1.JobApi;
+import org.apache.beam.model.jobmanagement.v1.JobServiceGrpc;
+import org.apache.beam.sdk.PipelineResult;
+import org.apache.beam.vendor.grpc.v1p60p1.io.grpc.ChannelCredentials;
+import org.apache.beam.vendor.grpc.v1p60p1.io.grpc.InsecureChannelCredentials;
+import org.apache.beam.vendor.grpc.v1p60p1.io.grpc.ManagedChannel;
+import org.apache.beam.vendor.grpc.v1p60p1.io.grpc.netty.NettyChannelBuilder;
+import org.apache.beam.vendor.grpc.v1p60p1.io.grpc.stub.StreamObserver;
+import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.net.HostAndPort;
+
+/**
+ * {@link StateWatcher} {@link #watch}es for and reports {@link PipelineResult.State} changes to
+ * {@link StateListener}s.
+ */
+@AutoValue
+abstract class StateWatcher implements AutoCloseable {
+
+  private Optional<PipelineResult.State> latestState = Optional.empty();
+
+  /**
+   * Instantiates a {@link StateWatcher} with {@link InsecureChannelCredentials}. {@link
+   * StateWatcher} will report to each {@link StateListener} of {@param listeners} of any changed
+   * {@link PipelineResult.State}.
+   */
+  static StateWatcher insecure(String endpoint, StateListener... listeners) {
+    return StateWatcher.builder()
+        .setEndpoint(HostAndPort.fromString(endpoint))
+        .setCredentials(InsecureChannelCredentials.create())
+        .setListeners(Arrays.asList(listeners))
+        .build();
+  }
+
+  /**
+   * Watch for a Job's {@link PipelineResult.State} change. A {@link
+   * org.apache.beam.model.jobmanagement.v1.JobApi.GetJobStateRequest} identifies a Job to watch via
+   * its {@link JobApi.GetJobStateRequest#getJobId()}. The method is blocking until the {@link
+   * JobApi.JobStateEvent} {@link StreamObserver#onCompleted()}.
+   */
+  void watch(String jobId) {
+    JobApi.GetJobStateRequest request =
+        JobApi.GetJobStateRequest.newBuilder().setJobId(jobId).build();
+    Iterator<JobApi.JobStateEvent> iterator = getJobServiceBlockingStub().getStateStream(request);
+    while (iterator.hasNext()) {
+      JobApi.JobStateEvent event = iterator.next();
+      PipelineResult.State state = PipelineResult.State.valueOf(event.getState().name());
+      publish(state);
+    }
+  }
+
+  private void publish(PipelineResult.State state) {
+    if (latestState.isPresent() && latestState.get().equals(state)) {
+      return;
+    }
+    latestState = Optional.of(state);
+    for (StateListener listener : getListeners()) {
+      listener.onStateChanged(state);
+    }
+  }
+
+  static Builder builder() {
+    return new AutoValue_StateWatcher.Builder();
+  }
+
+  abstract HostAndPort getEndpoint();
+
+  abstract ChannelCredentials getCredentials();
+
+  abstract List<StateListener> getListeners();
+
+  abstract ManagedChannel getManagedChannel();
+
+  abstract JobServiceGrpc.JobServiceBlockingStub getJobServiceBlockingStub();
+
+  @Override
+  public void close() {
+    getManagedChannel().shutdown();
+    try {
+      getManagedChannel().awaitTermination(3000L, TimeUnit.MILLISECONDS);
+    } catch (InterruptedException ignored) {
+    }
+  }
+
+  @AutoValue.Builder
+  abstract static class Builder {
+
+    abstract Builder setEndpoint(HostAndPort endpoint);
+
+    abstract Optional<HostAndPort> getEndpoint();
+
+    abstract Builder setCredentials(ChannelCredentials credentials);
+
+    abstract Optional<ChannelCredentials> getCredentials();
+
+    abstract Builder setListeners(List<StateListener> listeners);
+
+    abstract Builder setManagedChannel(ManagedChannel managedChannel);
+
+    abstract Builder setJobServiceBlockingStub(
+        JobServiceGrpc.JobServiceBlockingStub jobServiceBlockingStub);
+
+    abstract StateWatcher autoBuild();
+
+    final StateWatcher build() {
+      if (!getEndpoint().isPresent()) {
+        throw new IllegalStateException("missing endpoint");
+      }
+      if (!getCredentials().isPresent()) {
+        throw new IllegalStateException("missing credentials");
+      }
+      HostAndPort endpoint = getEndpoint().get();
+      ManagedChannel channel =
+          NettyChannelBuilder.forAddress(
+                  endpoint.getHost(), endpoint.getPort(), getCredentials().get())
+              .build();
+      setManagedChannel(channel);
+      setJobServiceBlockingStub(JobServiceGrpc.newBlockingStub(channel));
+
+      return autoBuild();
+    }
+  }
+}

runners/prism/java/src/test/java/org/apache/beam/runners/prism/StateWatcherTest.java

@@ -0,0 +1,136 @@
+/*
+ * 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.runners.prism;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import org.apache.beam.model.jobmanagement.v1.JobApi;
+import org.apache.beam.model.jobmanagement.v1.JobServiceGrpc;
+import org.apache.beam.sdk.PipelineResult;
+import org.apache.beam.vendor.grpc.v1p60p1.io.grpc.Grpc;
+import org.apache.beam.vendor.grpc.v1p60p1.io.grpc.InsecureServerCredentials;
+import org.apache.beam.vendor.grpc.v1p60p1.io.grpc.Server;
+import org.apache.beam.vendor.grpc.v1p60p1.io.grpc.stub.StreamObserver;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+@RunWith(JUnit4.class)
+public class StateWatcherTest {
+
+  @Test
+  public void givenSingleListener_watches() {
+    Server server = serverOf(PipelineResult.State.RUNNING, PipelineResult.State.DONE);
+    TestStateListener listener = new TestStateListener();
+    try (StateWatcher underTest = StateWatcher.insecure("0.0.0.0:" + server.getPort(), listener)) {
+      underTest.watch("job-001");
+      assertThat(listener.states)
+          .containsExactly(PipelineResult.State.RUNNING, PipelineResult.State.DONE);
+      shutdown(server);
+    }
+  }
+
+  @Test
+  public void givenMultipleListeners_watches() {
+    Server server = serverOf(PipelineResult.State.RUNNING, PipelineResult.State.DONE);
+    TestStateListener listenerA = new TestStateListener();
+    TestStateListener listenerB = new TestStateListener();
+    try (StateWatcher underTest =
+        StateWatcher.insecure("0.0.0.0:" + server.getPort(), listenerA, listenerB)) {
+      underTest.watch("job-001");
+      assertThat(listenerA.states)
+          .containsExactly(PipelineResult.State.RUNNING, PipelineResult.State.DONE);
+      assertThat(listenerB.states)
+          .containsExactly(PipelineResult.State.RUNNING, PipelineResult.State.DONE);
+      shutdown(server);
+    }
+  }
+
+  @Test
+  public void publishesOnlyChangedState() {
+    Server server =
+        serverOf(
+            PipelineResult.State.RUNNING,
+            PipelineResult.State.RUNNING,
+            PipelineResult.State.RUNNING,
+            PipelineResult.State.RUNNING,
+            PipelineResult.State.RUNNING,
+            PipelineResult.State.RUNNING,
+            PipelineResult.State.RUNNING,
+            PipelineResult.State.DONE);
+    TestStateListener listener = new TestStateListener();
+    try (StateWatcher underTest = StateWatcher.insecure("0.0.0.0:" + server.getPort(), listener)) {
+      underTest.watch("job-001");
+      assertThat(listener.states)
+          .containsExactly(PipelineResult.State.RUNNING, PipelineResult.State.DONE);
+      shutdown(server);
+    }
+  }
+
+  private static class TestStateListener implements StateListener {
+    private final List<PipelineResult.State> states = new ArrayList<>();
+
+    @Override
+    public void onStateChanged(PipelineResult.State state) {
+      states.add(state);
+    }
+  }
+
+  private static class TestJobServiceStateStream extends JobServiceGrpc.JobServiceImplBase {
+    private final List<PipelineResult.State> states;
+
+    TestJobServiceStateStream(PipelineResult.State... states) {
+      this.states = Arrays.asList(states);
+    }
+
+    @Override
+    public void getStateStream(
+        JobApi.GetJobStateRequest request, StreamObserver<JobApi.JobStateEvent> responseObserver) {
+      for (PipelineResult.State state : states) {
+        responseObserver.onNext(
+            JobApi.JobStateEvent.newBuilder()
+                .setState(JobApi.JobState.Enum.valueOf(state.name()))
+                .build());
+      }
+      responseObserver.onCompleted();
+    }
+  }
+
+  private static Server serverOf(PipelineResult.State... states) {
+    try {
+      return Grpc.newServerBuilderForPort(0, InsecureServerCredentials.create())
+          .addService(new TestJobServiceStateStream(states))
+          .build()
+          .start();
+    } catch (IOException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  private static void shutdown(Server server) {
+    server.shutdownNow();
+    try {
+      server.awaitTermination();
+    } catch (InterruptedException ignored) {
+    }
+  }
+}