[grid] Add a command to run the message bus as a standalone component

java/server/src/org/openqa/selenium/grid/commands/MessageBusCommand.java

@@ -0,0 +1,131 @@
+// Licensed to the Software Freedom Conservancy (SFC) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The SFC 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.openqa.selenium.grid.commands;
+
+import com.beust.jcommander.JCommander;
+import com.beust.jcommander.ParameterException;
+import com.google.auto.service.AutoService;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.net.MediaType;
+import org.openqa.selenium.BuildInfo;
+import org.openqa.selenium.cli.CliCommand;
+import org.openqa.selenium.events.EventBus;
+import org.openqa.selenium.grid.config.AnnotatedConfig;
+import org.openqa.selenium.grid.config.CompoundConfig;
+import org.openqa.selenium.grid.config.ConcatenatingConfig;
+import org.openqa.selenium.grid.config.Config;
+import org.openqa.selenium.grid.config.EnvConfig;
+import org.openqa.selenium.grid.config.MapConfig;
+import org.openqa.selenium.grid.log.LoggingOptions;
+import org.openqa.selenium.grid.server.BaseServerFlags;
+import org.openqa.selenium.grid.server.BaseServerOptions;
+import org.openqa.selenium.grid.server.EventBusFlags;
+import org.openqa.selenium.grid.server.EventBusOptions;
+import org.openqa.selenium.grid.server.HelpFlags;
+import org.openqa.selenium.grid.server.Server;
+import org.openqa.selenium.netty.server.NettyServer;
+import org.openqa.selenium.remote.http.Contents;
+import org.openqa.selenium.remote.http.HttpResponse;
+import org.openqa.selenium.remote.http.Route;
+
+import java.util.logging.Logger;
+
+@AutoService(CliCommand.class)
+public class MessageBusCommand implements CliCommand {
+  private static final Logger LOG = Logger.getLogger(MessageBusCommand.class.getName());
+
+  @Override
+  public String getName() {
+    return "message-bus";
+  }
+
+  @Override
+  public String getDescription() {
+    return "Standalone instance of the message bus.";
+  }
+
+  @Override
+  public boolean isShown() {
+    return false;
+  }
+
+  @Override
+  public Executable configure(String... args) {
+    HelpFlags help = new HelpFlags();
+    BaseServerFlags baseFlags = new BaseServerFlags(5557);
+    EventBusFlags eventBusFlags = new EventBusFlags();
+
+    JCommander commander = JCommander.newBuilder()
+      .programName("standalone")
+      .addObject(baseFlags)
+      .addObject(eventBusFlags)
+      .addObject(help)
+      .build();
+
+    return () -> {
+      try {
+        commander.parse(args);
+      } catch (ParameterException e) {
+        System.err.println(e.getMessage());
+        commander.usage();
+        return;
+      }
+
+      if (help.displayHelp(commander, System.out)) {
+        return;
+      }
+
+      Config config = new CompoundConfig(
+        new EnvConfig(),
+        new ConcatenatingConfig("message-bus", '.', System.getProperties()),
+        new AnnotatedConfig(help),
+        new AnnotatedConfig(eventBusFlags),
+        new AnnotatedConfig(baseFlags),
+        new MapConfig(ImmutableMap.of(
+          "events", ImmutableMap.of(
+            "bind", true,
+            "publish", "tcp://*:4442",
+            "subscribe", "tcp://*:4443"))));
+
+      LoggingOptions loggingOptions = new LoggingOptions(config);
+      loggingOptions.configureLogging();
+
+      EventBusOptions events = new EventBusOptions(config);
+      // We need this reference to stop the bus being garbage collected. Which would be less than ideal.
+      EventBus bus = events.getEventBus();
+
+      BaseServerOptions serverOptions = new BaseServerOptions(config);
+
+      Server<?> server = new NettyServer(
+        serverOptions,
+        Route.get("/status").to(() -> req ->
+          new HttpResponse()
+            .addHeader("Content-Type", MediaType.JSON_UTF_8.toString())
+            .setContent(Contents.asJson(ImmutableMap.of("ready", true, "message", "Event bus running")))));
+      server.start();
+
+      BuildInfo info = new BuildInfo();
+      LOG.info(String.format("Started Selenium message bus %s (revision %s)", info.getReleaseLabel(), info.getBuildRevision()));
+
+      // If we exit, the bus goes out of scope, and it's closed
+      Thread.currentThread().join();
+
+      LOG.info("Shutting down: " + bus);
+    };
+  }
+}