Adding HelloWorld example to grpc-java repo.

nmittler · nmittler · commit 87daf0e0dc5a · 2015-02-25T10:56:51.000-08:00
diff --git a/examples/README.md b/examples/README.md
@@ -1,16 +1,20 @@
 grpc Examples
 ==============================================
 
-In order to run the examples simply execute one of the gradle tasks `routeGuideServer` or
-`routeGuideClient`.
+In order to run the examples simply execute one of the gradle tasks `routeGuideServer`,
+`routeGuideClient`, `helloWorldServer`, or `helloWorldClient`.
 
-Assuming you are in the grpc-java root folder you would first start the server by running
+For example, say you want to play around with the route guide examples. First you want to start
+the server and then have the client connect to it and let the good times roll.
+
+Assuming you are in the grpc-java root folder you would first start the route guide server
+by running
 
 ```
 $ ./gradlew :grpc-examples:routeGuideServer
 ```
 
-and in a different terminal window then run the client by typing
+and in a different terminal window then run the route guide client by typing
 
 ```
 $ ./gradlew :grpc-examples:routeGuideClient
diff --git a/examples/build.gradle b/examples/build.gradle
@@ -34,3 +34,15 @@ task routeGuideClient(type: JavaExec) {
     description = "Executes the route guide client."
     classpath = sourceSets.main.runtimeClasspath
 }
+
+task helloWorldServer(type: JavaExec) {
+    main = "io.grpc.examples.HelloWorldServer"
+    description = "Executes the hello world server."
+    classpath = sourceSets.main.runtimeClasspath
+}
+
+task helloWorldClient(type: JavaExec) {
+    main = "io.grpc.examples.HelloWorldClient"
+    description = "Executes the hello world client."
+    classpath = sourceSets.main.runtimeClasspath
+}
diff --git a/examples/src/main/java/io/grpc/examples/HelloWorldClient.java b/examples/src/main/java/io/grpc/examples/HelloWorldClient.java
@@ -0,0 +1,58 @@
+package io.grpc.examples;
+
+import io.grpc.ChannelImpl;
+import io.grpc.examples.Helloworld.HelloReply;
+import io.grpc.examples.Helloworld.HelloRequest;
+import io.grpc.transport.netty.NegotiationType;
+import io.grpc.transport.netty.NettyChannelBuilder;
+
+import java.util.concurrent.TimeUnit;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * A simple client that requests a greeting from the {@link HelloWorldServer}.
+ */
+public class HelloWorldClient {
+  private static final Logger logger = Logger.getLogger(HelloWorldClient.class.getName());
+
+  private final ChannelImpl channel;
+  private final GreeterGrpc.GreeterBlockingStub blockingStub;
+
+  public HelloWorldClient(String host, int port) {
+    channel =
+        NettyChannelBuilder.forAddress(host, port).negotiationType(NegotiationType.PLAINTEXT)
+            .build();
+    blockingStub = GreeterGrpc.newBlockingStub(channel);
+  }
+
+  public void shutdown() throws InterruptedException {
+    channel.shutdown().awaitTerminated(5, TimeUnit.SECONDS);
+  }
+
+  public void greet(String name) {
+    try {
+      logger.info("Will try to greet " + name + " ...");
+      HelloRequest req = HelloRequest.newBuilder().setName(name).build();
+      HelloReply reply = blockingStub.sayHello(req);
+      logger.info("Greeting: " + reply.getMessage());
+    } catch (RuntimeException e) {
+      logger.log(Level.WARNING, "RPC failed", e);
+      return;
+    }
+  }
+
+  public static void main(String[] args) throws Exception {
+    HelloWorldClient client = new HelloWorldClient("localhost", 50051);
+    try {
+      /* Access a service running on the local machine on port 50051 */
+      String user = "world";
+      if (args.length > 0) {
+        user = args[0]; /* Use the arg as the name to greet if provided */
+      }
+      client.greet(user);
+    } finally {
+      client.shutdown();
+    }
+  }
+}
diff --git a/examples/src/main/java/io/grpc/examples/HelloWorldServer.java b/examples/src/main/java/io/grpc/examples/HelloWorldServer.java
@@ -0,0 +1,60 @@
+package io.grpc.examples;
+
+import io.grpc.ServerImpl;
+import io.grpc.examples.Helloworld.HelloReply;
+import io.grpc.examples.Helloworld.HelloRequest;
+import io.grpc.stub.StreamObserver;
+import io.grpc.transport.netty.NettyServerBuilder;
+
+import java.util.logging.Logger;
+
+/**
+ * Server that manages startup/shutdown of a {@code Greeter} server.
+ */
+public class HelloWorldServer {
+  private static final Logger logger = Logger.getLogger(HelloWorldServer.class.getName());
+
+  /* The port on which the server should run */
+  private int port = 50051;
+  private ServerImpl server;
+
+  private void start() throws Exception {
+    server = NettyServerBuilder.forPort(port)
+        .addService(GreeterGrpc.bindService(new GreeterImpl()))
+        .build().start();
+    logger.info("Server started, listening on " + port);
+    Runtime.getRuntime().addShutdownHook(new Thread() {
+      @Override
+      public void run() {
+        // Use stderr here since the logger may has been reset by its JVM shutdown hook.
+        System.err.println("*** shutting down gRPC server since JVM is shutting down");
+        HelloWorldServer.this.stop();
+        System.err.println("*** server shut down");
+      }
+    });
+  }
+
+  private void stop() {
+    if (server != null) {
+      server.shutdown();
+    }
+  }
+
+  /**
+   * Main launches the server from the command line.
+   */
+  public static void main(String[] args) throws Exception {
+    final HelloWorldServer server = new HelloWorldServer();
+    server.start();
+  }
+
+  private class GreeterImpl implements GreeterGrpc.Greeter {
+
+    @Override
+    public void sayHello(HelloRequest req, StreamObserver<HelloReply> responseObserver) {
+      HelloReply reply = HelloReply.newBuilder().setMessage("Hello " + req.getName()).build();
+      responseObserver.onValue(reply);
+      responseObserver.onCompleted();
+    }
+  }
+}
diff --git a/examples/src/main/java/io/grpc/examples/RouteGuideServer.java b/examples/src/main/java/io/grpc/examples/RouteGuideServer.java
@@ -88,8 +88,6 @@ public void start() {
         .addService(RouteGuideGrpc.bindService(new RouteGuideService(features)))
         .build().start();
     logger.info("Server started, listening on " + port);
-    // TODO(simonma): gRPC server should register JVM shutdown hook to shutdown itself, remove this
-    // after we support that.
     Runtime.getRuntime().addShutdownHook(new Thread() {
       @Override
       public void run() {
diff --git a/examples/src/main/proto/helloworld.proto b/examples/src/main/proto/helloworld.proto
@@ -0,0 +1,50 @@
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+syntax = "proto3";
+
+option java_package = "io.grpc.examples";
+
+package helloworld;
+
+// The greeting service definition.
+service Greeter {
+  // Sends a greeting
+  rpc SayHello (HelloRequest) returns (HelloReply) {}
+}
+
+// The request message containing the user's name.
+message HelloRequest {
+  string name = 1;
+}
+
+// The response message containing the greetings
+message HelloReply {
+  string message = 1;
+}
