core: add real transport test for retry buffer limit (#8354)

The unit tests in RetriableStreamTest do not really test buffer limit from end to end, because the buffer limit is implemented using ClientStreamTracer.Factory, and the tracer callback outboundMessageSize() is only triggered in AbstractClientStream after message serialization. In fact, it was broken without failing any existing tests (#8343 (comment))

This PR adds a retry buffer limit test that runs through the AbstractClientStream code path.

interop-testing/build.gradle

@@ -43,6 +43,7 @@ dependencies {
             libraries.netty_tcnative,
             project(':grpc-grpclb')
     testImplementation project(':grpc-context').sourceSets.test.output,
+            project(':grpc-api').sourceSets.test.output,
             libraries.mockito
     alpnagent libraries.jetty_alpn_agent
 }

interop-testing/src/test/java/io/grpc/testing/integration/RetryTest.java

@@ -0,0 +1,160 @@
+/*
+ * Copyright 2021 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.testing.integration;
+
+import static com.google.common.truth.Truth.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.timeout;
+import static org.mockito.Mockito.verify;
+
+import io.grpc.CallOptions;
+import io.grpc.ClientCall;
+import io.grpc.IntegerMarshaller;
+import io.grpc.ManagedChannel;
+import io.grpc.Metadata;
+import io.grpc.MethodDescriptor;
+import io.grpc.MethodDescriptor.MethodType;
+import io.grpc.Server;
+import io.grpc.ServerCall;
+import io.grpc.ServerCall.Listener;
+import io.grpc.ServerCallHandler;
+import io.grpc.ServerMethodDefinition;
+import io.grpc.ServerServiceDefinition;
+import io.grpc.Status;
+import io.grpc.StringMarshaller;
+import io.grpc.netty.NettyChannelBuilder;
+import io.grpc.netty.NettyServerBuilder;
+import io.grpc.testing.GrpcCleanupRule;
+import io.netty.channel.DefaultEventLoopGroup;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.local.LocalAddress;
+import io.netty.channel.local.LocalChannel;
+import io.netty.channel.local.LocalServerChannel;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.TimeUnit;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnit;
+import org.mockito.junit.MockitoRule;
+
+@RunWith(JUnit4.class)
+public class RetryTest {
+  @Rule
+  public final MockitoRule mocks = MockitoJUnit.rule();
+  @Rule
+  public final GrpcCleanupRule cleanupRule = new GrpcCleanupRule();
+  @Mock
+  private ClientCall.Listener<Integer> mockCallListener;
+
+  @Test
+  public void retryUntilBufferLimitExceeded() throws Exception {
+    String message = "String of length 20.";
+    int bufferLimit = message.length() * 2 - 1; // Can buffer no more than 1 message.
+
+    MethodDescriptor<String, Integer> clientStreamingMethod =
+        MethodDescriptor.<String, Integer>newBuilder()
+            .setType(MethodType.CLIENT_STREAMING)
+            .setFullMethodName("service/method")
+            .setRequestMarshaller(new StringMarshaller())
+            .setResponseMarshaller(new IntegerMarshaller())
+            .build();
+    final LinkedBlockingQueue<ServerCall<String, Integer>> serverCalls =
+        new LinkedBlockingQueue<>();
+    ServerMethodDefinition<String, Integer> methodDefinition = ServerMethodDefinition.create(
+        clientStreamingMethod,
+        new ServerCallHandler<String, Integer>() {
+          @Override
+          public Listener<String> startCall(ServerCall<String, Integer> call, Metadata headers) {
+            serverCalls.offer(call);
+            return new Listener<String>() {};
+          }
+        }
+    );
+    ServerServiceDefinition serviceDefinition =
+        ServerServiceDefinition.builder(clientStreamingMethod.getServiceName())
+            .addMethod(methodDefinition)
+            .build();
+    EventLoopGroup group = new DefaultEventLoopGroup();
+    LocalAddress localAddress = new LocalAddress("RetryTest.retryUntilBufferLimitExceeded");
+    Server localServer = cleanupRule.register(NettyServerBuilder.forAddress(localAddress)
+        .channelType(LocalServerChannel.class)
+        .bossEventLoopGroup(group)
+        .workerEventLoopGroup(group)
+        .addService(serviceDefinition)
+        .build());
+    localServer.start();
+
+    Map<String, Object> retryPolicy = new HashMap<>();
+    retryPolicy.put("maxAttempts", 4D);
+    retryPolicy.put("initialBackoff", "10s");
+    retryPolicy.put("maxBackoff", "10s");
+    retryPolicy.put("backoffMultiplier", 1D);
+    retryPolicy.put("retryableStatusCodes", Arrays.<Object>asList("UNAVAILABLE"));
+    Map<String, Object> methodConfig = new HashMap<>();
+    Map<String, Object> name = new HashMap<>();
+    name.put("service", "service");
+    methodConfig.put("name", Arrays.<Object>asList(name));
+    methodConfig.put("retryPolicy", retryPolicy);
+    Map<String, Object> rawServiceConfig = new HashMap<>();
+    rawServiceConfig.put("methodConfig", Arrays.<Object>asList(methodConfig));
+    ManagedChannel channel = cleanupRule.register(
+        NettyChannelBuilder.forAddress(localAddress)
+            .channelType(LocalChannel.class)
+            .eventLoopGroup(group)
+            .usePlaintext()
+            .enableRetry()
+            .perRpcBufferLimit(bufferLimit)
+            .defaultServiceConfig(rawServiceConfig)
+            .build());
+    ClientCall<String, Integer> call = channel.newCall(clientStreamingMethod, CallOptions.DEFAULT);
+    call.start(mockCallListener, new Metadata());
+    call.sendMessage(message);
+
+    ServerCall<String, Integer> serverCall = serverCalls.poll(5, TimeUnit.SECONDS);
+    serverCall.request(2);
+    // trigger retry
+    Metadata pushBackMetadata = new Metadata();
+    pushBackMetadata.put(
+        Metadata.Key.of("grpc-retry-pushback-ms", Metadata.ASCII_STRING_MARSHALLER),
+        "0");   // retry immediately
+    serverCall.close(
+        Status.UNAVAILABLE.withDescription("original attempt failed"),
+        pushBackMetadata);
+    // 2nd attempt received
+    serverCall = serverCalls.poll(5, TimeUnit.SECONDS);
+    serverCall.request(2);
+    verify(mockCallListener, never()).onClose(any(Status.class), any(Metadata.class));
+    // send one more message, should exceed buffer limit
+    call.sendMessage(message);
+    // let attempt fail
+    serverCall.close(
+        Status.UNAVAILABLE.withDescription("2nd attempt failed"),
+        new Metadata());
+    // no more retry
+    ArgumentCaptor<Status> statusCaptor = ArgumentCaptor.forClass(null);
+    verify(mockCallListener, timeout(5000)).onClose(statusCaptor.capture(), any(Metadata.class));
+    assertThat(statusCaptor.getValue().getDescription()).contains("2nd attempt failed");
+  }
+}