inprocess,core: add ability to pass status cause to client

Closes #5439

core/src/main/java/io/grpc/inprocess/InProcessChannelBuilder.java

@@ -70,6 +70,7 @@ public final class InProcessChannelBuilder extends
   private final String name;
   private ScheduledExecutorService scheduledExecutorService;
   private int maxInboundMetadataSize = Integer.MAX_VALUE;
+  private boolean transportIncludeStatusCause = false;
 
   private InProcessChannelBuilder(String name) {
     super(new InProcessSocketAddress(name), "localhost");
@@ -157,11 +158,30 @@ public final class InProcessChannelBuilder extends
     return this;
   }
 
+  /**
+   * Sets whether to include the cause with the status that is propagated
+   * forward from the InProcessTransport. This was added to make debugging failing
+   * tests easier by showing the cause of the status.
+   *
+   * <p>By default, this is set to false.
+   * A default value of false maintains consistency with other transports which strip causal
+   * information from the status to avoid leaking information to untrusted clients, and
+   * to avoid sharing language-specific information with the client.
+   * For the in-process implementation, this is not a concern.
+   *
+   * @param enable whether to include cause in status
+   * @return this
+   */
+  public InProcessChannelBuilder propagateCauseWithStatus(boolean enable) {
+    this.transportIncludeStatusCause = enable;
+    return this;
+  }
+
   @Override
   @Internal
   protected ClientTransportFactory buildTransportFactory() {
     return new InProcessClientTransportFactory(
-        name, scheduledExecutorService, maxInboundMetadataSize);
+        name, scheduledExecutorService, maxInboundMetadataSize, transportIncludeStatusCause);
   }
 
   /**
@@ -173,16 +193,18 @@ public final class InProcessChannelBuilder extends
     private final boolean useSharedTimer;
     private final int maxInboundMetadataSize;
     private boolean closed;
+    private boolean includeCauseWithStatus;
 
     private InProcessClientTransportFactory(
         String name,
         @Nullable ScheduledExecutorService scheduledExecutorService,
-        int maxInboundMetadataSize) {
+        int maxInboundMetadataSize, boolean includeCauseWithStatus) {
       this.name = name;
       useSharedTimer = scheduledExecutorService == null;
       timerService = useSharedTimer
           ? SharedResourceHolder.get(GrpcUtil.TIMER_SERVICE) : scheduledExecutorService;
       this.maxInboundMetadataSize = maxInboundMetadataSize;
+      this.includeCauseWithStatus = includeCauseWithStatus;
     }
 
     @Override
@@ -194,7 +216,7 @@ public final class InProcessChannelBuilder extends
       // TODO(carl-mastrangelo): Pass channelLogger in.
       return new InProcessTransport(
           name, maxInboundMetadataSize, options.getAuthority(), options.getUserAgent(),
-          options.getEagAttributes());
+          options.getEagAttributes(), includeCauseWithStatus);
     }
 
     @Override

core/src/main/java/io/grpc/inprocess/InProcessTransport.java

@@ -83,6 +83,7 @@ final class InProcessTransport implements ServerTransport, ConnectionClientTrans
   private final String userAgent;
   private final Optional<ServerListener> optionalServerListener;
   private int serverMaxInboundMetadataSize;
+  private final boolean includeCauseWithStatus;
   private ObjectPool<ScheduledExecutorService> serverSchedulerPool;
   private ScheduledExecutorService serverScheduler;
   private ServerTransportListener serverTransportListener;
@@ -115,7 +116,8 @@ final class InProcessTransport implements ServerTransport, ConnectionClientTrans
       };
 
   private InProcessTransport(String name, int maxInboundMetadataSize, String authority,
-      String userAgent, Attributes eagAttrs, Optional<ServerListener> optionalServerListener) {
+      String userAgent, Attributes eagAttrs,
+      Optional<ServerListener> optionalServerListener, boolean includeCauseWithStatus) {
     this.name = name;
     this.clientMaxInboundMetadataSize = maxInboundMetadataSize;
     this.authority = authority;
@@ -129,13 +131,14 @@ final class InProcessTransport implements ServerTransport, ConnectionClientTrans
         .build();
     this.optionalServerListener = optionalServerListener;
     logId = InternalLogId.allocate(getClass(), name);
+    this.includeCauseWithStatus = includeCauseWithStatus;
   }
 
   public InProcessTransport(
       String name, int maxInboundMetadataSize, String authority, String userAgent,
-      Attributes eagAttrs) {
+      Attributes eagAttrs, boolean includeCauseWithStatus) {
     this(name, maxInboundMetadataSize, authority, userAgent, eagAttrs,
-        Optional.<ServerListener>absent());
+        Optional.<ServerListener>absent(), includeCauseWithStatus);
   }
 
   InProcessTransport(
@@ -143,7 +146,8 @@ final class InProcessTransport implements ServerTransport, ConnectionClientTrans
       Attributes eagAttrs, ObjectPool<ScheduledExecutorService> serverSchedulerPool,
       List<ServerStreamTracer.Factory> serverStreamTracerFactories,
       ServerListener serverListener) {
-    this(name, maxInboundMetadataSize, authority, userAgent, eagAttrs, Optional.of(serverListener));
+    this(name, maxInboundMetadataSize, authority, userAgent, eagAttrs,
+        Optional.of(serverListener), false);
     this.serverMaxInboundMetadataSize = maxInboundMetadataSize;
     this.serverSchedulerPool = serverSchedulerPool;
     this.serverStreamTracerFactories = serverStreamTracerFactories;
@@ -564,7 +568,7 @@ final class InProcessTransport implements ServerTransport, ConnectionClientTrans
 
       /** clientStream.serverClosed() must be called before this method */
       private void notifyClientClose(Status status, Metadata trailers) {
-        Status clientStatus = stripCause(status);
+        Status clientStatus = cleanStatus(status, includeCauseWithStatus);
         synchronized (this) {
           if (closed) {
             return;
@@ -744,7 +748,7 @@ final class InProcessTransport implements ServerTransport, ConnectionClientTrans
       // Must be thread-safe for shutdownNow()
       @Override
       public void cancel(Status reason) {
-        Status serverStatus = stripCause(reason);
+        Status serverStatus = cleanStatus(reason, includeCauseWithStatus);
         if (!internalCancel(serverStatus, serverStatus)) {
           return;
         }
@@ -843,19 +847,25 @@ final class InProcessTransport implements ServerTransport, ConnectionClientTrans
   }
 
   /**
-   * Returns a new status with the same code and description, but stripped of any other information
+   * Returns a new status with the same code and description.
-   * (i.e. cause).
+   * If includeCauseWithStatus is true, cause is also included.
    *
-   * <p>This is, so that the InProcess transport behaves in the same way as the other transports,
+   * <p>For InProcess transport to behave in the same way as the other transports,
-   * when exchanging statuses between client and server and vice versa.
+   * when exchanging statuses between client and server and vice versa,
+   * the cause should be excluded from the status.
+   * For easier debugging, the status may be optionally included.
    */
-  private static Status stripCause(Status status) {
+  private static Status cleanStatus(Status status, boolean includeCauseWithStatus) {
     if (status == null) {
       return null;
     }
-    return Status
+    Status clientStatus = Status
         .fromCodeValue(status.getCode().value())
         .withDescription(status.getDescription());
+    if (includeCauseWithStatus) {
+      clientStatus = clientStatus.withCause(status.getCause());
+    }
+    return clientStatus;
   }
 
   private static class SingleMessageProducer implements StreamListener.MessageProducer {

core/src/main/java/io/grpc/internal/ServerImpl.java

@@ -161,7 +161,6 @@ public final class ServerImpl extends io.grpc.Server implements InternalInstrume
     this.channelz = builder.channelz;
     this.serverCallTracer = builder.callTracerFactory.create();
     this.ticker = checkNotNull(builder.ticker, "ticker");
-
     channelz.addServer(this);
   }
 
@@ -762,9 +761,9 @@ public final class ServerImpl extends io.grpc.Server implements InternalInstrume
     /**
      * Like {@link ServerCall#close(Status, Metadata)}, but thread-safe for internal use.
      */
-    private void internalClose() {
+    private void internalClose(Throwable t) {
       // TODO(ejona86): this is not thread-safe :)
-      stream.close(Status.UNKNOWN, new Metadata());
+      stream.close(Status.UNKNOWN.withCause(t), new Metadata());
     }
 
     @Override
@@ -785,10 +784,10 @@ public final class ServerImpl extends io.grpc.Server implements InternalInstrume
           try {
             getListener().messagesAvailable(producer);
           } catch (RuntimeException e) {
-            internalClose();
+            internalClose(e);
             throw e;
           } catch (Error e) {
-            internalClose();
+            internalClose(e);
             throw e;
           } finally {
             PerfMark.stopTask("ServerCallListener(app).messagesAvailable", tag);
@@ -820,10 +819,10 @@ public final class ServerImpl extends io.grpc.Server implements InternalInstrume
           try {
             getListener().halfClosed();
           } catch (RuntimeException e) {
-            internalClose();
+            internalClose(e);
             throw e;
           } catch (Error e) {
-            internalClose();
+            internalClose(e);
             throw e;
           } finally {
             PerfMark.stopTask("ServerCallListener(app).halfClosed", tag);
@@ -894,10 +893,10 @@ public final class ServerImpl extends io.grpc.Server implements InternalInstrume
           try {
             getListener().onReady();
           } catch (RuntimeException e) {
-            internalClose();
+            internalClose(e);
             throw e;
           } catch (Error e) {
-            internalClose();
+            internalClose(e);
             throw e;
           } finally {
             PerfMark.stopTask("ServerCallListener(app).onReady", tag);

core/src/test/java/io/grpc/inprocess/InProcessTransportTest.java

@@ -16,14 +16,30 @@
 
 package io.grpc.inprocess;
 
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
 import com.google.common.collect.ImmutableList;
+import io.grpc.CallOptions;
+import io.grpc.ManagedChannel;
+import io.grpc.Metadata;
+import io.grpc.Server;
+import io.grpc.ServerCall;
+import io.grpc.ServerCallHandler;
+import io.grpc.ServerServiceDefinition;
 import io.grpc.ServerStreamTracer;
+import io.grpc.Status;
+import io.grpc.StatusRuntimeException;
 import io.grpc.internal.AbstractTransportTest;
 import io.grpc.internal.GrpcUtil;
 import io.grpc.internal.InternalServer;
 import io.grpc.internal.ManagedClientTransport;
+import io.grpc.stub.ClientCalls;
+import io.grpc.testing.GrpcCleanupRule;
+import io.grpc.testing.TestMethodDescriptors;
 import java.util.List;
 import org.junit.Ignore;
+import org.junit.Rule;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
@@ -35,6 +51,9 @@ public class InProcessTransportTest extends AbstractTransportTest {
   private static final String AUTHORITY = "a-testing-authority";
   private static final String USER_AGENT = "a-testing-user-agent";
 
+  @Rule
+  public final GrpcCleanupRule grpcCleanupRule = new GrpcCleanupRule();
+
   @Override
   protected List<? extends InternalServer> newServer(
       List<ServerStreamTracer.Factory> streamTracerFactories) {
@@ -59,7 +78,7 @@ public class InProcessTransportTest extends AbstractTransportTest {
   protected ManagedClientTransport newClientTransport(InternalServer server) {
     return new InProcessTransport(
         TRANSPORT_NAME, GrpcUtil.DEFAULT_MAX_HEADER_LIST_SIZE, testAuthority(server), USER_AGENT,
-        eagAttrs());
+        eagAttrs(), false);
   }
 
   @Override
@@ -75,4 +94,42 @@ public class InProcessTransportTest extends AbstractTransportTest {
   public void socketStats() throws Exception {
     // test does not apply to in-process
   }
+
+  @Test
+  public void causeShouldBePropagatedWithStatus() throws Exception {
+    server = null;
+    String failingServerName = "server_foo";
+    String serviceFoo = "service_foo";
+    final Status s = Status.INTERNAL.withCause(new Throwable("failing server exception"));
+    ServerServiceDefinition definition = ServerServiceDefinition.builder(serviceFoo)
+        .addMethod(TestMethodDescriptors.voidMethod(), new ServerCallHandler<Void, Void>() {
+          @Override
+          public ServerCall.Listener<Void> startCall(
+              ServerCall<Void, Void> call, Metadata headers) {
+            call.close(s, new Metadata());
+            return new ServerCall.Listener<Void>() {};
+          }
+        })
+        .build();
+    Server failingServer = InProcessServerBuilder
+        .forName(failingServerName)
+        .addService(definition)
+        .directExecutor()
+        .build()
+        .start();
+    grpcCleanupRule.register(failingServer);
+    ManagedChannel channel = InProcessChannelBuilder
+        .forName(failingServerName)
+        .propagateCauseWithStatus(true)
+        .build();
+    grpcCleanupRule.register(channel);
+    try {
+      ClientCalls.blockingUnaryCall(channel, TestMethodDescriptors.voidMethod(),
+          CallOptions.DEFAULT, null);
+      fail("exception should have been thrown");
+    } catch (StatusRuntimeException e) {
+      // When propagateCauseWithStatus is true, the cause should be sent forward
+      assertEquals(s.getCause(), e.getCause());
+    }
+  }
 }

core/src/test/java/io/grpc/internal/AbstractTransportTest.java

@@ -157,7 +157,7 @@ public abstract class AbstractTransportTest {
    * {@code serverListener}, otherwise tearDown() can't wait for shutdown which can put following
    * tests in an indeterminate state.
    */
-  private InternalServer server;
+  protected InternalServer server;
   private ServerTransport serverTransport;
   private ManagedClientTransport client;
   private MethodDescriptor<String, String> methodDescriptor =
@@ -1058,9 +1058,7 @@ public abstract class AbstractTransportTest {
     Metadata clientStreamTrailers =
         clientStreamListener.trailers.get(TIMEOUT_MS, TimeUnit.MILLISECONDS);
     assertNotNull(clientStreamTrailers);
-    assertEquals(status.getCode(), clientStreamStatus.getCode());
+    checkClientStatus(status, clientStreamStatus);
-    assertEquals("Hello. Goodbye.", clientStreamStatus.getDescription());
-    assertNull(clientStreamStatus.getCause());
     assertTrue(clientStreamTracer1.getOutboundHeaders());
     assertTrue(clientStreamTracer1.getInboundHeaders());
     assertSame(clientStreamTrailers, clientStreamTracer1.getInboundTrailers());
@@ -1097,10 +1095,7 @@ public abstract class AbstractTransportTest {
     Status clientStreamStatus = clientStreamListener.status.get(TIMEOUT_MS, TimeUnit.MILLISECONDS);
     Metadata clientStreamTrailers =
         clientStreamListener.trailers.get(TIMEOUT_MS, TimeUnit.MILLISECONDS);
-    assertEquals(status.getCode(), clientStreamStatus.getCode());
+    checkClientStatus(status, clientStreamStatus);
-    assertEquals("Hellogoodbye", clientStreamStatus.getDescription());
-    // Cause should not be transmitted to the client.
-    assertNull(clientStreamStatus.getCause());
     assertEquals(
         Lists.newArrayList(trailers.getAll(asciiKey)),
         Lists.newArrayList(clientStreamTrailers.getAll(asciiKey)));
@@ -1138,9 +1133,7 @@ public abstract class AbstractTransportTest {
     Metadata clientStreamTrailers =
         clientStreamListener.trailers.get(TIMEOUT_MS, TimeUnit.MILLISECONDS);
     assertNotNull(clientStreamTrailers);
-    assertEquals(status.getCode(), clientStreamStatus.getCode());
+    checkClientStatus(status, clientStreamStatus);
-    assertEquals(status.getDescription(), clientStreamStatus.getDescription());
-    assertNull(clientStreamStatus.getCause());
     assertTrue(clientStreamTracer1.getOutboundHeaders());
     assertSame(clientStreamTrailers, clientStreamTracer1.getInboundTrailers());
     assertSame(clientStreamStatus, clientStreamTracer1.getStatus());
@@ -1188,9 +1181,7 @@ public abstract class AbstractTransportTest {
     Metadata clientStreamTrailers =
         clientStreamListener.trailers.get(TIMEOUT_MS, TimeUnit.MILLISECONDS);
     assertNotNull(clientStreamTrailers);
-    assertEquals(status.getCode(), clientStreamStatus.getCode());
+    checkClientStatus(status, clientStreamStatus);
-    assertEquals(status.getDescription(), clientStreamStatus.getDescription());
-    assertNull(clientStreamStatus.getCause());
     assertTrue(clientStreamTracer1.getOutboundHeaders());
     assertSame(clientStreamTrailers, clientStreamTracer1.getInboundTrailers());
     assertSame(clientStreamStatus, clientStreamTracer1.getStatus());
@@ -1219,7 +1210,7 @@ public abstract class AbstractTransportTest {
     assertNotNull(clientStreamListener.trailers.get(TIMEOUT_MS, TimeUnit.MILLISECONDS));
     Status serverStatus = serverStreamListener.status.get(TIMEOUT_MS, TimeUnit.MILLISECONDS);
     assertNotEquals(Status.Code.OK, serverStatus.getCode());
-    // Cause should not be transmitted between client and server
+    // Cause should not be transmitted between client and server by default
     assertNull(serverStatus.getCause());
 
     clientStream.cancel(status);
@@ -2072,6 +2063,16 @@ public abstract class AbstractTransportTest {
     }
   }
 
+  /**
+   * Verifies that the client status is as expected. By default, the code and description should
+   * be present, and the cause should be stripped away.
+   */
+  private void checkClientStatus(Status expectedStatus, Status clientStreamStatus) {
+    assertEquals(expectedStatus.getCode(), clientStreamStatus.getCode());
+    assertEquals(expectedStatus.getDescription(), clientStreamStatus.getDescription());
+    assertNull(clientStreamStatus.getCause());
+  }
+
   private static boolean waitForFuture(Future<?> future, long timeout, TimeUnit unit)
       throws InterruptedException {
     try {

core/src/test/java/io/grpc/internal/ServerImplTest.java

@@ -1441,8 +1441,9 @@ public class ServerImplTest {
 
   private void ensureServerStateNotLeaked() {
     verify(stream).close(statusCaptor.capture(), metadataCaptor.capture());
-    assertEquals(Status.UNKNOWN, statusCaptor.getValue());
+    assertEquals(Status.UNKNOWN.getCode(), statusCaptor.getValue().getCode());
-    assertNull(statusCaptor.getValue().getCause());
+    // Used in InProcessTransport when set to include the cause with the status
+    assertNotNull(statusCaptor.getValue().getCause());
     assertTrue(metadataCaptor.getValue().keys().isEmpty());
   }