diff --git a/examples/src/main/java/io/grpc/examples/errorhandling/ErrorHandlingClient.java b/examples/src/main/java/io/grpc/examples/errorhandling/ErrorHandlingClient.java new file mode 100644 index 0000000000..072d14dd02 --- /dev/null +++ b/examples/src/main/java/io/grpc/examples/errorhandling/ErrorHandlingClient.java @@ -0,0 +1,216 @@ +/* + * Copyright 2016, 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. + */ + +package io.grpc.examples.errorhandling; + +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 io.grpc.CallOptions; +import io.grpc.ClientCall; +import io.grpc.ManagedChannel; +import io.grpc.ManagedChannelBuilder; +import io.grpc.Metadata; +import io.grpc.Server; +import io.grpc.ServerBuilder; +import io.grpc.Status; +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.stub.StreamObserver; + +import java.util.concurrent.CountDownLatch; +import java.util.concurrent.ExecutionException; +import java.util.concurrent.TimeUnit; + +import javax.annotation.Nullable; + +/** + * Shows how to extract error information from a server response. + */ +public class ErrorHandlingClient { + public static void main(String [] args) throws Exception { + new ErrorHandlingClient().run(); + } + + private Server server; + private ManagedChannel channel; + + void run() throws Exception { + server = ServerBuilder.forPort(0).addService(new GreeterGrpc.AbstractGreeter() { + @Override + public void sayHello(HelloRequest request, StreamObserver responseObserver) { + responseObserver.onError(Status.INTERNAL + .withDescription("Eggplant Xerxes Crybaby Overbite Narwhal").asRuntimeException()); + } + }).build().start(); + channel = + ManagedChannelBuilder.forAddress("localhost", server.getPort()).usePlaintext(true).build(); + + blockingCall(); + futureCallDirect(); + futureCallCallback(); + asyncCall(); + advancedAsyncCall(); + + channel.shutdown(); + server.shutdown(); + channel.awaitTermination(1, TimeUnit.SECONDS); + server.awaitTermination(); + } + + void blockingCall() { + GreeterBlockingStub stub = GreeterGrpc.newBlockingStub(channel); + try { + stub.sayHello(HelloRequest.newBuilder().setName("Bart").build()); + } catch (Exception e) { + Status status = Status.fromThrowable(e); + Verify.verify(status.getCode() == Status.Code.INTERNAL); + Verify.verify(status.getDescription().contains("Eggplant")); + // Cause is not transmitted over the wire. + } + } + + void futureCallDirect() { + GreeterFutureStub stub = GreeterGrpc.newFutureStub(channel); + ListenableFuture response = + stub.sayHello(HelloRequest.newBuilder().setName("Lisa").build()); + + try { + response.get(); + } catch (InterruptedException e) { + Thread.currentThread().interrupt(); + throw new RuntimeException(e); + } catch (ExecutionException e) { + Status status = Status.fromThrowable(e.getCause()); + Verify.verify(status.getCode() == Status.Code.INTERNAL); + Verify.verify(status.getDescription().contains("Xerxes")); + // Cause is not transmitted over the wire. + } + } + + void futureCallCallback() { + GreeterFutureStub stub = GreeterGrpc.newFutureStub(channel); + ListenableFuture response = + stub.sayHello(HelloRequest.newBuilder().setName("Maggie").build()); + + final CountDownLatch latch = new CountDownLatch(1); + + Futures.addCallback(response, new FutureCallback() { + @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) { + Status status = Status.fromThrowable(t); + Verify.verify(status.getCode() == Status.Code.INTERNAL); + Verify.verify(status.getDescription().contains("Crybaby")); + // Cause is not transmitted over the wire.. + latch.countDown(); + } + }); + + if (!Uninterruptibles.awaitUninterruptibly(latch, 1, TimeUnit.SECONDS)) { + throw new RuntimeException("timeout!"); + } + } + + void asyncCall() { + GreeterStub stub = GreeterGrpc.newStub(channel); + HelloRequest request = HelloRequest.newBuilder().setName("Homer").build(); + final CountDownLatch latch = new CountDownLatch(1); + StreamObserver responseObserver = new StreamObserver() { + + @Override + public void onNext(HelloReply value) { + // Won't be called. + } + + @Override + public void onError(Throwable t) { + Status status = Status.fromThrowable(t); + Verify.verify(status.getCode() == Status.Code.INTERNAL); + Verify.verify(status.getDescription().contains("Overbite")); + // Cause is not transmitted over the wire.. + 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!"); + } + } + + + /** + * This is more advanced and does not make use of the stub. You should not normally need to do + * this, but here is how you would. + */ + void advancedAsyncCall() { + ClientCall call = + channel.newCall(GreeterGrpc.METHOD_SAY_HELLO, CallOptions.DEFAULT); + + final CountDownLatch latch = new CountDownLatch(1); + + call.start(new ClientCall.Listener() { + + @Override + public void onClose(Status status, Metadata trailers) { + Verify.verify(status.getCode() == Status.Code.INTERNAL); + Verify.verify(status.getDescription().contains("Narwhal")); + // Cause is not transmitted over the wire. + latch.countDown(); + } + }, new Metadata()); + + call.sendMessage(HelloRequest.newBuilder().setName("Marge").build()); + call.halfClose(); + + if (!Uninterruptibles.awaitUninterruptibly(latch, 1, TimeUnit.SECONDS)) { + throw new RuntimeException("timeout!"); + } + } +} +