[Prism]: Enable ExternalWorkerService during Prism Runner lifecycle

runners/prism/java/build.gradle

@@ -27,7 +27,9 @@ ext.summary = "Support for executing a pipeline on Prism."
 
 dependencies {
     implementation project(path: ":model:job-management", configuration: "shadow")
+    implementation project(path: ":model:pipeline", configuration: "shadow")
     implementation project(path: ":sdks:java:core", configuration: "shadow")
+    implementation project(path: ":sdks:java:harness", configuration: "shadow")
     implementation project(":runners:portability:java")
 
     implementation library.java.joda_time

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

@@ -0,0 +1,116 @@
+/*
+ * 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 org.apache.beam.sdk.util.Preconditions.checkStateNotNull;
+
+import org.apache.beam.fn.harness.ExternalWorkerService;
+import org.apache.beam.model.pipeline.v1.Endpoints;
+import org.apache.beam.sdk.PipelineResult;
+import org.apache.beam.sdk.fn.server.GrpcFnServer;
+import org.apache.beam.sdk.options.PortablePipelineOptions;
+import org.apache.beam.vendor.grpc.v1p60p1.io.grpc.Server;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * An {@link ExternalWorkerService} {@link GrpcFnServer} encapsulation that {@link #stop}s when
+ * {@link StateListener#onStateChanged} is invoked with a {@link PipelineResult.State} that is
+ * {@link PipelineResult.State#isTerminal}.
+ */
+class WorkerService implements StateListener {
+
+  private static final Logger LOG = LoggerFactory.getLogger(WorkerService.class);
+
+  private final ExternalWorkerService worker;
+  private @MonotonicNonNull GrpcFnServer<ExternalWorkerService> server;
+
+  WorkerService(PortablePipelineOptions options) {
+    this.worker = new ExternalWorkerService(options);
+  }
+
+  /** Start the {@link ExternalWorkerService}. */
+  void start() throws Exception {
+    if (server != null && !server.getServer().isShutdown()) {
+      return;
+    }
+
+    server = worker.start();
+    LOG.info("Starting worker service at {}", getApiServiceDescriptorUrl());
+  }
+
+  /**
+   * Queries whether the {@link ExternalWorkerService} {@link GrpcFnServer}'s {@link Server} is
+   * running.
+   */
+  boolean isRunning() {
+    if (server == null) {
+      return false;
+    }
+    return !server.getServer().isShutdown();
+  }
+
+  /**
+   * Queries the {@link Endpoints.ApiServiceDescriptor#getUrl} of the {@link ExternalWorkerService}
+   * {@link GrpcFnServer}'s {@link Server}. Throws an exception if the {@link WorkerService} has not
+   * {@link WorkerService#start}ed.
+   */
+  String getApiServiceDescriptorUrl() {
+    return checkStateNotNull(server, "worker service not started")
+        .getApiServiceDescriptor()
+        .getUrl();
+  }
+
+  /**
+   * Updates {@link PortablePipelineOptions#getDefaultEnvironmentConfig} with {@link
+   * #getApiServiceDescriptorUrl}. Throws an exception if the {@link WorkerService} has not {@link
+   * WorkerService#start}ed.
+   */
+  PortablePipelineOptions updateDefaultEnvironmentConfig(PortablePipelineOptions options) {
+    options.setDefaultEnvironmentConfig(getApiServiceDescriptorUrl());
+    return options;
+  }
+
+  /**
+   * Overrides {@link StateListener#onStateChanged}, invoking {@link #stop} when {@link
+   * PipelineResult.State#isTerminal}.
+   */
+  @Override
+  public void onStateChanged(PipelineResult.State state) {
+    if (state.isTerminal()) {
+      stop();
+    }
+  }
+
+  /**
+   * Stops the {@link ExternalWorkerService} {@link GrpcFnServer}'s {@link Server}. If not {@link
+   * WorkerService#isRunning()}, then calling stop is a noop.
+   */
+  void stop() {
+    if (server == null || server.getServer().isShutdown()) {
+      return;
+    }
+    LOG.info("Stopping worker service at {}", getApiServiceDescriptorUrl());
+    try {
+      server.close();
+    } catch (Exception e) {
+      throw new RuntimeException(e);
+    }
+  }
+}

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

@@ -0,0 +1,85 @@
+/*
+ * 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 static org.junit.Assert.assertThrows;
+
+import org.apache.beam.sdk.PipelineResult;
+import org.apache.beam.sdk.options.PipelineOptionsFactory;
+import org.apache.beam.sdk.options.PortablePipelineOptions;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/** Tests for {@link WorkerService}. */
+@RunWith(JUnit4.class)
+public class WorkerServiceTest {
+  @Test
+  public void testStartStop() throws Exception {
+    PortablePipelineOptions options =
+        PipelineOptionsFactory.create().as(PortablePipelineOptions.class);
+    WorkerService underTest = new WorkerService(options);
+    underTest.start();
+    assertThat(underTest.isRunning()).isTrue();
+    assertThat(underTest.getApiServiceDescriptorUrl()).matches("localhost:\\d+");
+    underTest.stop();
+    assertThat(underTest.isRunning()).isFalse();
+  }
+
+  @Test
+  public void givenStarted_updateDefaultEnvironmentConfig() throws Exception {
+    PortablePipelineOptions options =
+        PipelineOptionsFactory.create().as(PortablePipelineOptions.class);
+    assertThat(options.getDefaultEnvironmentConfig()).isNull();
+    WorkerService underTest = new WorkerService(options);
+    underTest.start();
+    options = underTest.updateDefaultEnvironmentConfig(options);
+    assertThat(options.getDefaultEnvironmentConfig())
+        .isEqualTo(underTest.getApiServiceDescriptorUrl());
+    underTest.stop();
+  }
+
+  @Test
+  public void givenNotStarted_updateDefaultEnvironmentConfig_throws() {
+    PortablePipelineOptions options =
+        PipelineOptionsFactory.create().as(PortablePipelineOptions.class);
+    WorkerService underTest = new WorkerService(options);
+    assertThrows(
+        IllegalStateException.class, () -> underTest.updateDefaultEnvironmentConfig(options));
+  }
+
+  @Test
+  public void whenStateIsTerminal_thenStop() throws Exception {
+    PortablePipelineOptions options =
+        PipelineOptionsFactory.create().as(PortablePipelineOptions.class);
+    WorkerService underTest = new WorkerService(options);
+    assertThat(underTest.isRunning()).isFalse();
+    underTest.start();
+    assertThat(underTest.isRunning()).isTrue();
+
+    underTest.onStateChanged(PipelineResult.State.RUNNING);
+    assertThat(underTest.isRunning()).isTrue();
+
+    underTest.onStateChanged(PipelineResult.State.RUNNING);
+    assertThat(underTest.isRunning()).isTrue();
+
+    underTest.onStateChanged(PipelineResult.State.CANCELLED);
+    assertThat(underTest.isRunning()).isFalse();
+  }
+}