examples: Error details example

examples/build.gradle

@@ -252,6 +252,13 @@ task sharingClient(type: CreateStartScripts) {
     classpath = startScripts.classpath
 }
 
+task errorDetails(type: CreateStartScripts) {
+    mainClass = 'io.grpc.examples.errordetails.DetailErrorSample'
+    applicationName = 'error-details'
+    outputDir = new File(project.buildDir, 'tmp/scripts/' + name)
+    classpath = startScripts.classpath
+}
+
 applicationDistribution.into('bin') {
     from(routeGuideServer)
     from(routeGuideClient)
@@ -280,5 +287,6 @@ applicationDistribution.into('bin') {
     from(cancellationServer)
     from(multiplexingServer)
     from(sharingClient)
+    from(errorDetails)
     fileMode = 0755
 }

examples/src/main/java/io/grpc/examples/errordetails/DetailErrorSample.java

@@ -0,0 +1,199 @@
+/*
+ * Copyright 2016 The gRPC Authors
+ *
+ * Licensed 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 io.grpc.examples.errordetails;
+
+import static com.google.common.util.concurrent.MoreExecutors.directExecutor;
+
+import com.google.common.base.Verify;
+import com.google.common.util.concurrent.FutureCallback;
+import com.google.common.util.concurrent.Futures;
+import com.google.common.util.concurrent.ListenableFuture;
+import com.google.common.util.concurrent.Uninterruptibles;
+import com.google.protobuf.Any;
+import com.google.protobuf.InvalidProtocolBufferException;
+import com.google.rpc.Code;
+import com.google.rpc.DebugInfo;
+import com.google.rpc.Status;
+import io.grpc.Grpc;
+import io.grpc.InsecureChannelCredentials;
+import io.grpc.InsecureServerCredentials;
+import io.grpc.ManagedChannel;
+import io.grpc.Metadata;
+import io.grpc.Server;
+import io.grpc.examples.helloworld.GreeterGrpc;
+import io.grpc.examples.helloworld.GreeterGrpc.GreeterBlockingStub;
+import io.grpc.examples.helloworld.GreeterGrpc.GreeterFutureStub;
+import io.grpc.examples.helloworld.GreeterGrpc.GreeterStub;
+import io.grpc.examples.helloworld.HelloReply;
+import io.grpc.examples.helloworld.HelloRequest;
+import io.grpc.protobuf.ProtoUtils;
+import io.grpc.protobuf.StatusProto;
+import io.grpc.stub.StreamObserver;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import javax.annotation.Nullable;
+
+/**
+ * Shows how to set and read com.google.rpc.Status objects as google.rpc.Status error details.
+ */
+public class DetailErrorSample {
+  private static final Metadata.Key<DebugInfo> DEBUG_INFO_TRAILER_KEY =
+      ProtoUtils.keyForProto(DebugInfo.getDefaultInstance());
+
+  private static final DebugInfo DEBUG_INFO =
+      DebugInfo.newBuilder()
+          .addStackEntries("stack_entry_1")
+          .addStackEntries("stack_entry_2")
+          .addStackEntries("stack_entry_3")
+          .setDetail("detailed error info.").build();
+
+  private static final String DEBUG_DESC = "detailed error description";
+
+  public static void main(String[] args) throws Exception {
+    new DetailErrorSample().run();
+  }
+
+  private ManagedChannel channel;
+
+  void run() throws Exception {
+    Server server = Grpc.newServerBuilderForPort(0, InsecureServerCredentials.create())
+        .addService(new GreeterGrpc.GreeterImplBase() {
+      @Override
+      public void sayHello(HelloRequest request, StreamObserver<HelloReply> responseObserver) {
+        // This is com.google.rpc.Status, not io.grpc.Status
+        Status status = Status.newBuilder()
+            .setCode(Code.INVALID_ARGUMENT.getNumber())
+            .setMessage("Email or password malformed")
+            .addDetails(Any.pack(DEBUG_INFO))
+            .build();
+        responseObserver.onError(StatusProto.toStatusRuntimeException(status));
+      }
+    }).build().start();
+    channel = Grpc.newChannelBuilderForAddress(
+          "localhost", server.getPort(), InsecureChannelCredentials.create()).build();
+
+    blockingCall();
+    futureCallDirect();
+    futureCallCallback();
+    asyncCall();
+
+    channel.shutdown();
+    server.shutdown();
+    channel.awaitTermination(1, TimeUnit.SECONDS);
+    server.awaitTermination();
+  }
+
+  static void verifyErrorReply(Throwable t) {
+    Status status = StatusProto.fromThrowable(t);
+    Verify.verify(status.getCode() == Code.INVALID_ARGUMENT.getNumber());
+    Verify.verify(status.getMessage().equals("Email or password malformed"));
+    try {
+      DebugInfo unpackedDetail = status.getDetails(0).unpack(DebugInfo.class);
+      Verify.verify(unpackedDetail.equals(DEBUG_INFO));
+    } catch (InvalidProtocolBufferException e) {
+      Verify.verify(false, "Message was a different type than expected");
+    }
+
+  }
+
+  void blockingCall() {
+    GreeterBlockingStub stub = GreeterGrpc.newBlockingStub(channel);
+    try {
+      stub.sayHello(HelloRequest.newBuilder().build());
+    } catch (Exception e) {
+      verifyErrorReply(e);
+      System.out.println("blocking call received expected error");
+    }
+  }
+
+  void futureCallDirect() {
+    GreeterFutureStub stub = GreeterGrpc.newFutureStub(channel);
+    ListenableFuture<HelloReply> response =
+        stub.sayHello(HelloRequest.newBuilder().build());
+
+    try {
+      response.get();
+    } catch (InterruptedException e) {
+      Thread.currentThread().interrupt();
+      throw new RuntimeException(e);
+    } catch (ExecutionException e) {
+      verifyErrorReply(e.getCause());
+      System.out.println("future call direct received expected error");
+    }
+  }
+
+  void futureCallCallback() {
+    GreeterFutureStub stub = GreeterGrpc.newFutureStub(channel);
+    ListenableFuture<HelloReply> response =
+        stub.sayHello(HelloRequest.newBuilder().build());
+
+    final CountDownLatch latch = new CountDownLatch(1);
+
+    Futures.addCallback(
+        response,
+        new FutureCallback<HelloReply>() {
+          @Override
+          public void onSuccess(@Nullable HelloReply result) {
+            // Won't be called, since the server in this example always fails.
+          }
+
+          @Override
+          public void onFailure(Throwable t) {
+            verifyErrorReply(t);
+            System.out.println("future callback received expected error");
+            latch.countDown();
+          }
+        },
+        directExecutor());
+
+    if (!Uninterruptibles.awaitUninterruptibly(latch, 1, TimeUnit.SECONDS)) {
+      throw new RuntimeException("timeout!");
+    }
+  }
+
+  void asyncCall() {
+    GreeterStub stub = GreeterGrpc.newStub(channel);
+    HelloRequest request = HelloRequest.newBuilder().build();
+    final CountDownLatch latch = new CountDownLatch(1);
+    StreamObserver<HelloReply> responseObserver = new StreamObserver<HelloReply>() {
+
+      @Override
+      public void onNext(HelloReply value) {
+        // Won't be called.
+      }
+
+      @Override
+      public void onError(Throwable t) {
+        verifyErrorReply(t);
+        System.out.println("Async call received expected error");
+        latch.countDown();
+      }
+
+      @Override
+      public void onCompleted() {
+        // Won't be called, since the server in this example always fails.
+      }
+    };
+    stub.sayHello(request, responseObserver);
+
+    if (!Uninterruptibles.awaitUninterruptibly(latch, 1, TimeUnit.SECONDS)) {
+      throw new RuntimeException("timeout!");
+    }
+  }
+}
+