Java Code Examples for io.grpc.ClientCall#halfClose()

/**
 * 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<HelloRequest, HelloReply> call =
      channel.newCall(GreeterGrpc.getSayHelloMethod(), CallOptions.DEFAULT);

  final CountDownLatch latch = new CountDownLatch(1);

  call.start(new ClientCall.Listener<HelloReply>() {

    @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!");
  }
}
 

/**
 * 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<HelloRequest, HelloReply> call =
      channel.newCall(GreeterGrpc.getSayHelloMethod(), CallOptions.DEFAULT);

  final CountDownLatch latch = new CountDownLatch(1);

  call.start(new ClientCall.Listener<HelloReply>() {

    @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!");
  }
}
 

/**
 * 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<HelloRequest, HelloReply> call =
      channel.newCall(GreeterGrpc.getSayHelloMethod(), CallOptions.DEFAULT);

  final CountDownLatch latch = new CountDownLatch(1);

  call.start(new ClientCall.Listener<HelloReply>() {

    @Override
    public void onClose(Status status, Metadata trailers) {
      Verify.verify(status.getCode() == Status.Code.INTERNAL);
      Verify.verify(trailers.containsKey(DEBUG_INFO_TRAILER_KEY));
      try {
        Verify.verify(trailers.get(DEBUG_INFO_TRAILER_KEY).equals(DEBUG_INFO));
      } catch (IllegalArgumentException e) {
        throw new VerifyException(e);
      }

      latch.countDown();
    }
  }, new Metadata());

  call.sendMessage(HelloRequest.newBuilder().build());
  call.halfClose();

  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<HelloRequest, HelloReply> call =
      channel.newCall(GreeterGrpc.getSayHelloMethod(), CallOptions.DEFAULT);

  final CountDownLatch latch = new CountDownLatch(1);

  call.start(new ClientCall.Listener<HelloReply>() {

    @Override
    public void onClose(Status status, Metadata trailers) {
      Verify.verify(status.getCode() == Status.Code.INTERNAL);
      Verify.verify(trailers.containsKey(DEBUG_INFO_TRAILER_KEY));
      try {
        Verify.verify(trailers.get(DEBUG_INFO_TRAILER_KEY).equals(DEBUG_INFO));
      } catch (IllegalArgumentException e) {
        throw new VerifyException(e);
      }

      latch.countDown();
    }
  }, new Metadata());

  call.sendMessage(HelloRequest.newBuilder().build());
  call.halfClose();

  if (!Uninterruptibles.awaitUninterruptibly(latch, 1, TimeUnit.SECONDS)) {
    throw new RuntimeException("timeout!");
  }
}
 

@Test
public void serverStreamingShouldBeFlowControlled() throws Exception {
  final StreamingOutputCallRequest request = StreamingOutputCallRequest.newBuilder()
      .addResponseParameters(ResponseParameters.newBuilder().setSize(100000))
      .addResponseParameters(ResponseParameters.newBuilder().setSize(100001))
      .build();
  final List<StreamingOutputCallResponse> goldenResponses = Arrays.asList(
      StreamingOutputCallResponse.newBuilder()
          .setPayload(Payload.newBuilder()
              .setBody(ByteString.copyFrom(new byte[100000]))).build(),
      StreamingOutputCallResponse.newBuilder()
          .setPayload(Payload.newBuilder()
              .setBody(ByteString.copyFrom(new byte[100001]))).build());

  long start = System.nanoTime();

  final ArrayBlockingQueue<Object> queue = new ArrayBlockingQueue<>(10);
  ClientCall<StreamingOutputCallRequest, StreamingOutputCallResponse> call =
      channel.newCall(TestServiceGrpc.getStreamingOutputCallMethod(), CallOptions.DEFAULT);
  call.start(new ClientCall.Listener<StreamingOutputCallResponse>() {
    @Override
    public void onHeaders(Metadata headers) {}

    @Override
    public void onMessage(final StreamingOutputCallResponse message) {
      queue.add(message);
    }

    @Override
    public void onClose(Status status, Metadata trailers) {
      queue.add(status);
    }
  }, new Metadata());
  call.sendMessage(request);
  call.halfClose();

  // Time how long it takes to get the first response.
  call.request(1);
  Object response = queue.poll(operationTimeoutMillis(), TimeUnit.MILLISECONDS);
  assertTrue(response instanceof StreamingOutputCallResponse);
  assertResponse(goldenResponses.get(0), (StreamingOutputCallResponse) response);
  long firstCallDuration = System.nanoTime() - start;

  // Without giving additional flow control, make sure that we don't get another response. We wait
  // until we are comfortable the next message isn't coming. We may have very low nanoTime
  // resolution (like on Windows) or be using a testing, in-process transport where message
  // handling is instantaneous. In both cases, firstCallDuration may be 0, so round up sleep time
  // to at least 1ms.
  assertNull(queue.poll(Math.max(firstCallDuration * 4, 1 * 1000 * 1000), TimeUnit.NANOSECONDS));

  // Make sure that everything still completes.
  call.request(1);
  response = queue.poll(operationTimeoutMillis(), TimeUnit.MILLISECONDS);
  assertTrue(response instanceof StreamingOutputCallResponse);
  assertResponse(goldenResponses.get(1), (StreamingOutputCallResponse) response);
  assertEquals(Status.OK, queue.poll(operationTimeoutMillis(), TimeUnit.MILLISECONDS));
}
 

@Test
public void inprocessTransportManualFlow() throws Exception {
  final Semaphore semaphore = new Semaphore(1);
  ServerServiceDefinition service = ServerServiceDefinition.builder(
      new ServiceDescriptor("some", STREAMING_METHOD))
      .addMethod(STREAMING_METHOD, ServerCalls.asyncBidiStreamingCall(
          new ServerCalls.BidiStreamingMethod<Integer, Integer>() {
            int iteration;

            @Override
            public StreamObserver<Integer> invoke(StreamObserver<Integer> responseObserver) {
              final ServerCallStreamObserver<Integer> serverCallObserver =
                  (ServerCallStreamObserver<Integer>) responseObserver;
              serverCallObserver.setOnReadyHandler(new Runnable() {
                @Override
                public void run() {
                  while (serverCallObserver.isReady()) {
                    serverCallObserver.onNext(iteration);
                  }
                  iteration++;
                  semaphore.release();
                }
              });
              return new ServerCalls.NoopStreamObserver<Integer>() {
                @Override
                public void onCompleted() {
                  serverCallObserver.onCompleted();
                }
              };
            }
          }))
      .build();
  long tag = System.nanoTime();
  InProcessServerBuilder.forName("go-with-the-flow" + tag).addService(service).build().start();
  ManagedChannel channel = InProcessChannelBuilder.forName("go-with-the-flow" + tag).build();
  final ClientCall<Integer, Integer> clientCall = channel.newCall(STREAMING_METHOD,
      CallOptions.DEFAULT);
  final CountDownLatch latch = new CountDownLatch(1);
  final int[] receivedMessages = new int[6];
  clientCall.start(new ClientCall.Listener<Integer>() {
    int index;

    @Override
    public void onMessage(Integer message) {
      receivedMessages[index++] = message;
    }

    @Override
    public void onClose(Status status, Metadata trailers) {
      latch.countDown();
    }
  }, new Metadata());
  semaphore.acquire();
  clientCall.request(1);
  semaphore.acquire();
  clientCall.request(2);
  semaphore.acquire();
  clientCall.request(3);
  clientCall.halfClose();
  latch.await(5, TimeUnit.SECONDS);
  // Very that number of messages produced in each onReady handler call matches the number
  // requested by the client.
  assertArrayEquals(new int[]{0, 1, 1, 2, 2, 2}, receivedMessages);
}
 

@Test
public void writePutsIntoBlobStore() throws IOException, InterruptedException {
  ByteString helloWorld = ByteString.copyFromUtf8("Hello, World!");
  Digest digest = DIGEST_UTIL.compute(helloWorld);
  String uuid = UUID.randomUUID().toString();
  String resourceName = createBlobUploadResourceName(uuid, digest);

  Channel channel = InProcessChannelBuilder.forName(fakeServerName).directExecutor().build();
  ClientCall<WriteRequest, WriteResponse> call =
      channel.newCall(ByteStreamGrpc.getWriteMethod(), CallOptions.DEFAULT);
  ClientCall.Listener<WriteResponse> callListener =
      new ClientCall.Listener<WriteResponse>() {
        boolean complete = false;
        boolean callHalfClosed = false;

        @Override
        public void onReady() {
          while (call.isReady()) {
            if (complete) {
              if (!callHalfClosed) {
                call.halfClose();
                callHalfClosed = true;
              }
              return;
            }

            call.sendMessage(
                WriteRequest.newBuilder()
                    .setResourceName(resourceName)
                    .setData(helloWorld)
                    .setFinishWrite(true)
                    .build());
            complete = true;
          }
        }
      };

  call.start(callListener, new Metadata());
  call.request(1);

  verify(simpleBlobStore, times(1))
      .put(eq(digest.getHash()), eq(digest.getSizeBytes()), any(InputStream.class));
}
 

@Test
public void writeCanBeResumed() throws IOException, InterruptedException {
  ByteString helloWorld = ByteString.copyFromUtf8("Hello, World!");
  Digest digest = DIGEST_UTIL.compute(helloWorld);
  String uuid = UUID.randomUUID().toString();
  String resourceName = createBlobUploadResourceName(uuid, digest);

  Channel channel = InProcessChannelBuilder.forName(fakeServerName).directExecutor().build();
  ClientCall<WriteRequest, WriteResponse> initialCall =
      channel.newCall(ByteStreamGrpc.getWriteMethod(), CallOptions.DEFAULT);
  ByteString initialData = helloWorld.substring(0, 6);
  ClientCall.Listener<WriteResponse> initialCallListener =
      new ClientCall.Listener<WriteResponse>() {
        boolean complete = false;
        boolean callHalfClosed = false;

        @Override
        public void onReady() {
          while (initialCall.isReady()) {
            if (complete) {
              if (!callHalfClosed) {
                initialCall.halfClose();
                callHalfClosed = true;
              }
              return;
            }

            initialCall.sendMessage(
                WriteRequest.newBuilder()
                    .setResourceName(resourceName)
                    .setData(initialData)
                    .build());
            complete = true;
          }
        }
      };

  initialCall.start(initialCallListener, new Metadata());
  initialCall.request(1);

  ByteStreamBlockingStub service = ByteStreamGrpc.newBlockingStub(channel);
  QueryWriteStatusResponse response =
      service.queryWriteStatus(
          QueryWriteStatusRequest.newBuilder().setResourceName(resourceName).build());
  assertThat(response.getCommittedSize()).isEqualTo(initialData.size());
  assertThat(response.getComplete()).isFalse();

  ClientCall<WriteRequest, WriteResponse> finishCall =
      channel.newCall(ByteStreamGrpc.getWriteMethod(), CallOptions.DEFAULT);
  ClientCall.Listener<WriteResponse> finishCallListener =
      new ClientCall.Listener<WriteResponse>() {
        boolean complete = false;
        boolean callHalfClosed = false;

        @Override
        public void onReady() {
          while (finishCall.isReady()) {
            if (complete) {
              if (!callHalfClosed) {
                finishCall.halfClose();
                callHalfClosed = true;
              }
              return;
            }

            finishCall.sendMessage(
                WriteRequest.newBuilder()
                    .setResourceName(resourceName)
                    .setWriteOffset(initialData.size())
                    .setData(helloWorld.substring(initialData.size()))
                    .setFinishWrite(true)
                    .build());
            complete = true;
          }
        }
      };

  finishCall.start(finishCallListener, new Metadata());
  finishCall.request(1);

  ArgumentCaptor<InputStream> inputStreamCaptor = ArgumentCaptor.forClass(InputStream.class);

  verify(simpleBlobStore, times(1))
      .put(eq(digest.getHash()), eq(digest.getSizeBytes()), inputStreamCaptor.capture());
  InputStream inputStream = inputStreamCaptor.getValue();
  assertThat(inputStream.available()).isEqualTo(helloWorld.size());
  byte[] data = new byte[helloWorld.size()];
  assertThat(inputStream.read(data)).isEqualTo(helloWorld.size());
  assertThat(data).isEqualTo(helloWorld.toByteArray());
}
 

@Test
public void serverStreamingShouldBeFlowControlled() throws Exception {
  final StreamingOutputCallRequest request = StreamingOutputCallRequest.newBuilder()
      .addResponseParameters(ResponseParameters.newBuilder().setSize(100000))
      .addResponseParameters(ResponseParameters.newBuilder().setSize(100001))
      .build();
  final List<StreamingOutputCallResponse> goldenResponses = Arrays.asList(
      StreamingOutputCallResponse.newBuilder()
          .setPayload(Payload.newBuilder()
              .setBody(ByteString.copyFrom(new byte[100000]))).build(),
      StreamingOutputCallResponse.newBuilder()
          .setPayload(Payload.newBuilder()
              .setBody(ByteString.copyFrom(new byte[100001]))).build());

  long start = System.nanoTime();

  final ArrayBlockingQueue<Object> queue = new ArrayBlockingQueue<>(10);
  ClientCall<StreamingOutputCallRequest, StreamingOutputCallResponse> call =
      channel.newCall(TestServiceGrpc.getStreamingOutputCallMethod(), CallOptions.DEFAULT);
  call.start(new ClientCall.Listener<StreamingOutputCallResponse>() {
    @Override
    public void onHeaders(Metadata headers) {}

    @Override
    public void onMessage(final StreamingOutputCallResponse message) {
      queue.add(message);
    }

    @Override
    public void onClose(Status status, Metadata trailers) {
      queue.add(status);
    }
  }, new Metadata());
  call.sendMessage(request);
  call.halfClose();

  // Time how long it takes to get the first response.
  call.request(1);
  Object response = queue.poll(operationTimeoutMillis(), TimeUnit.MILLISECONDS);
  assertTrue(response instanceof StreamingOutputCallResponse);
  assertResponse(goldenResponses.get(0), (StreamingOutputCallResponse) response);
  long firstCallDuration = System.nanoTime() - start;

  // Without giving additional flow control, make sure that we don't get another response. We wait
  // until we are comfortable the next message isn't coming. We may have very low nanoTime
  // resolution (like on Windows) or be using a testing, in-process transport where message
  // handling is instantaneous. In both cases, firstCallDuration may be 0, so round up sleep time
  // to at least 1ms.
  assertNull(queue.poll(Math.max(firstCallDuration * 4, 1 * 1000 * 1000), TimeUnit.NANOSECONDS));

  // Make sure that everything still completes.
  call.request(1);
  response = queue.poll(operationTimeoutMillis(), TimeUnit.MILLISECONDS);
  assertTrue(response instanceof StreamingOutputCallResponse);
  assertResponse(goldenResponses.get(1), (StreamingOutputCallResponse) response);
  assertEquals(Status.OK, queue.poll(operationTimeoutMillis(), TimeUnit.MILLISECONDS));
}
 

private void runQps() throws InterruptedException, ExecutionException {
  final SettableFuture<Void> failure = SettableFuture.create();
  final class PeriodicRpc implements Runnable {

    @Override
    public void run() {
      final long requestId;
      final Set<XdsStatsWatcher> savedWatchers = new HashSet<>();
      synchronized (lock) {
        currentRequestId += 1;
        requestId = currentRequestId;
        savedWatchers.addAll(watchers);
      }

      SimpleRequest request = SimpleRequest.newBuilder().setFillServerId(true).build();
      ManagedChannel channel = channels.get((int) (requestId % channels.size()));
      final ClientCall<SimpleRequest, SimpleResponse> call =
          channel.newCall(
              TestServiceGrpc.getUnaryCallMethod(),
              CallOptions.DEFAULT.withDeadlineAfter(rpcTimeoutSec, TimeUnit.SECONDS));
      call.start(
          new ClientCall.Listener<SimpleResponse>() {
            private String hostname;

            @Override
            public void onMessage(SimpleResponse response) {
              hostname = response.getHostname();
              // TODO(ericgribkoff) Currently some test environments cannot access the stats RPC
              // service and rely on parsing stdout.
              if (printResponse) {
                System.out.println(
                    "Greeting: Hello world, this is "
                        + hostname
                        + ", from "
                        + call.getAttributes().get(Grpc.TRANSPORT_ATTR_REMOTE_ADDR));
              }
            }

            @Override
            public void onClose(Status status, Metadata trailers) {
              if (printResponse && !status.isOk()) {
                logger.log(Level.WARNING, "Greeting RPC failed with status {0}", status);
              }
              for (XdsStatsWatcher watcher : savedWatchers) {
                watcher.rpcCompleted(requestId, hostname);
              }
            }
          },
          new Metadata());

      call.sendMessage(request);
      call.request(1);
      call.halfClose();
    }
  }

  long nanosPerQuery = TimeUnit.SECONDS.toNanos(1) / qps;
  ListenableScheduledFuture<?> future =
      exec.scheduleAtFixedRate(new PeriodicRpc(), 0, nanosPerQuery, TimeUnit.NANOSECONDS);

  Futures.addCallback(
      future,
      new FutureCallback<Object>() {

        @Override
        public void onFailure(Throwable t) {
          failure.setException(t);
        }

        @Override
        public void onSuccess(Object o) {}
      },
      MoreExecutors.directExecutor());

  failure.get();
}
 

private void channelsAndSubchannels_instrumented0(boolean success) throws Exception {
  createChannel();

  ClientCall<String, Integer> call = channel.newCall(method, CallOptions.DEFAULT);

  // Channel stat bumped when ClientCall.start() called
  assertEquals(0, getStats(channel).callsStarted);
  call.start(mockCallListener, new Metadata());
  assertEquals(1, getStats(channel).callsStarted);

  ClientStream mockStream = mock(ClientStream.class);
  ClientStreamTracer.Factory factory = mock(ClientStreamTracer.Factory.class);
  AbstractSubchannel subchannel =
      (AbstractSubchannel) createSubchannelSafely(
          helper, addressGroup, Attributes.EMPTY, subchannelStateListener);
  requestConnectionSafely(helper, subchannel);
  MockClientTransportInfo transportInfo = transports.poll();
  transportInfo.listener.transportReady();
  ClientTransport mockTransport = transportInfo.transport;
  when(mockTransport.newStream(
          any(MethodDescriptor.class), any(Metadata.class), any(CallOptions.class)))
      .thenReturn(mockStream);
  when(mockPicker.pickSubchannel(any(PickSubchannelArgs.class))).thenReturn(
      PickResult.withSubchannel(subchannel, factory));

  // subchannel stat bumped when call gets assigned to it
  assertEquals(0, getStats(subchannel).callsStarted);
  updateBalancingStateSafely(helper, READY, mockPicker);
  assertEquals(1, executor.runDueTasks());
  verify(mockStream).start(streamListenerCaptor.capture());
  assertEquals(1, getStats(subchannel).callsStarted);

  ClientStreamListener streamListener = streamListenerCaptor.getValue();
  call.halfClose();

  // closing stream listener affects subchannel stats immediately
  assertEquals(0, getStats(subchannel).callsSucceeded);
  assertEquals(0, getStats(subchannel).callsFailed);
  streamListener.closed(success ? Status.OK : Status.UNKNOWN, new Metadata());
  if (success) {
    assertEquals(1, getStats(subchannel).callsSucceeded);
    assertEquals(0, getStats(subchannel).callsFailed);
  } else {
    assertEquals(0, getStats(subchannel).callsSucceeded);
    assertEquals(1, getStats(subchannel).callsFailed);
  }

  // channel stats bumped when the ClientCall.Listener is notified
  assertEquals(0, getStats(channel).callsSucceeded);
  assertEquals(0, getStats(channel).callsFailed);
  executor.runDueTasks();
  if (success) {
    assertEquals(1, getStats(channel).callsSucceeded);
    assertEquals(0, getStats(channel).callsFailed);
  } else {
    assertEquals(0, getStats(channel).callsSucceeded);
    assertEquals(1, getStats(channel).callsFailed);
  }
}
 

private void channelsAndSubchannels_oob_instrumented0(boolean success) throws Exception {
  // set up
  ClientStream mockStream = mock(ClientStream.class);
  createChannel();

  OobChannel oobChannel = (OobChannel) helper.createOobChannel(addressGroup, "oobauthority");
  AbstractSubchannel oobSubchannel = (AbstractSubchannel) oobChannel.getSubchannel();
  FakeClock callExecutor = new FakeClock();
  CallOptions options =
      CallOptions.DEFAULT.withExecutor(callExecutor.getScheduledExecutorService());
  ClientCall<String, Integer> call = oobChannel.newCall(method, options);
  Metadata headers = new Metadata();

  // Channel stat bumped when ClientCall.start() called
  assertEquals(0, getStats(oobChannel).callsStarted);
  call.start(mockCallListener, headers);
  assertEquals(1, getStats(oobChannel).callsStarted);

  MockClientTransportInfo transportInfo = transports.poll();
  ConnectionClientTransport mockTransport = transportInfo.transport;
  ManagedClientTransport.Listener transportListener = transportInfo.listener;
  when(mockTransport.newStream(same(method), same(headers), any(CallOptions.class)))
      .thenReturn(mockStream);

  // subchannel stat bumped when call gets assigned to it
  assertEquals(0, getStats(oobSubchannel).callsStarted);
  transportListener.transportReady();
  callExecutor.runDueTasks();
  verify(mockStream).start(streamListenerCaptor.capture());
  assertEquals(1, getStats(oobSubchannel).callsStarted);

  ClientStreamListener streamListener = streamListenerCaptor.getValue();
  call.halfClose();

  // closing stream listener affects subchannel stats immediately
  assertEquals(0, getStats(oobSubchannel).callsSucceeded);
  assertEquals(0, getStats(oobSubchannel).callsFailed);
  streamListener.closed(success ? Status.OK : Status.UNKNOWN, new Metadata());
  if (success) {
    assertEquals(1, getStats(oobSubchannel).callsSucceeded);
    assertEquals(0, getStats(oobSubchannel).callsFailed);
  } else {
    assertEquals(0, getStats(oobSubchannel).callsSucceeded);
    assertEquals(1, getStats(oobSubchannel).callsFailed);
  }

  // channel stats bumped when the ClientCall.Listener is notified
  assertEquals(0, getStats(oobChannel).callsSucceeded);
  assertEquals(0, getStats(oobChannel).callsFailed);
  callExecutor.runDueTasks();
  if (success) {
    assertEquals(1, getStats(oobChannel).callsSucceeded);
    assertEquals(0, getStats(oobChannel).callsFailed);
  } else {
    assertEquals(0, getStats(oobChannel).callsSucceeded);
    assertEquals(1, getStats(oobChannel).callsFailed);
  }
  // oob channel is separate from the original channel
  assertEquals(0, getStats(channel).callsSucceeded);
  assertEquals(0, getStats(channel).callsFailed);
}
 

@Test
public void inprocessTransportManualFlow() throws Exception {
  final Semaphore semaphore = new Semaphore(1);
  ServerServiceDefinition service = ServerServiceDefinition.builder(
      new ServiceDescriptor("some", STREAMING_METHOD))
      .addMethod(STREAMING_METHOD, ServerCalls.asyncBidiStreamingCall(
          new ServerCalls.BidiStreamingMethod<Integer, Integer>() {
            int iteration;

            @Override
            public StreamObserver<Integer> invoke(StreamObserver<Integer> responseObserver) {
              final ServerCallStreamObserver<Integer> serverCallObserver =
                  (ServerCallStreamObserver<Integer>) responseObserver;
              serverCallObserver.setOnReadyHandler(new Runnable() {
                @Override
                public void run() {
                  while (serverCallObserver.isReady()) {
                    serverCallObserver.onNext(iteration);
                  }
                  iteration++;
                  semaphore.release();
                }
              });
              return new ServerCalls.NoopStreamObserver<Integer>() {
                @Override
                public void onCompleted() {
                  serverCallObserver.onCompleted();
                }
              };
            }
          }))
      .build();
  long tag = System.nanoTime();
  InProcessServerBuilder.forName("go-with-the-flow" + tag).addService(service).build().start();
  ManagedChannel channel = InProcessChannelBuilder.forName("go-with-the-flow" + tag).build();
  final ClientCall<Integer, Integer> clientCall = channel.newCall(STREAMING_METHOD,
      CallOptions.DEFAULT);
  final CountDownLatch latch = new CountDownLatch(1);
  final int[] receivedMessages = new int[6];
  clientCall.start(new ClientCall.Listener<Integer>() {
    int index;

    @Override
    public void onMessage(Integer message) {
      receivedMessages[index++] = message;
    }

    @Override
    public void onClose(Status status, Metadata trailers) {
      latch.countDown();
    }
  }, new Metadata());
  semaphore.acquire();
  clientCall.request(1);
  semaphore.acquire();
  clientCall.request(2);
  semaphore.acquire();
  clientCall.request(3);
  clientCall.halfClose();
  assertThat(latch.await(5, TimeUnit.SECONDS)).isTrue();
  // Very that number of messages produced in each onReady handler call matches the number
  // requested by the client.
  assertArrayEquals(new int[]{0, 1, 1, 2, 2, 2}, receivedMessages);
}