Polish gRPC lifecycle

spring-cloud-function-adapters/spring-cloud-function-grpc/src/main/java/org/springframework/cloud/function/grpc/GrpcUtils.java

@@ -83,12 +83,16 @@ final class GrpcUtils {
 	public static Message<byte[]> requestReply(String host, int port, Message<byte[]> inputMessage) {
 		ManagedChannel channel = ManagedChannelBuilder.forAddress(host, port)
 				.usePlaintext().build();
-		MessagingServiceGrpc.MessagingServiceBlockingStub stub = MessagingServiceGrpc
+		try {
-				.newBlockingStub(channel);
+			MessagingServiceGrpc.MessagingServiceBlockingStub stub = MessagingServiceGrpc
+					.newBlockingStub(channel);
 
-		GrpcSpringMessage response = stub.requestReply(toGrpcSpringMessage(inputMessage));
+			GrpcSpringMessage response = stub.requestReply(toGrpcSpringMessage(inputMessage));
-		channel.shutdown();
+			return fromGrpcSpringMessage(response);
-		return fromGrpcSpringMessage(response);
+		}
+		finally {
+			channel.shutdownNow();
+		}
 	}
 
 	/**
@@ -129,7 +133,11 @@ final class GrpcUtils {
 
 		return sink.asFlux().doOnComplete(() -> {
 			logger.debug("Shutting down channel");
-			channel.shutdown();
+			channel.shutdownNow();
+		})
+		.doOnError(e -> {
+			e.printStackTrace();
+			channel.shutdownNow();
 		});
 	}
 
@@ -151,10 +159,14 @@ final class GrpcUtils {
 			sink.tryEmitComplete();
 		});
 
-
 		return sink.asFlux()
 				.doOnComplete(() -> {
-					channel.shutdown();
+					channel.shutdownNow();
+					executor.shutdownNow();
+				})
+				.doOnError(e -> {
+					e.printStackTrace();
+					channel.shutdownNow();
 					executor.shutdownNow();
 				});
 	}
@@ -196,11 +208,13 @@ final class GrpcUtils {
 			@Override
 			public void onError(Throwable t) {
 				t.printStackTrace();
+				channel.shutdownNow();
 			}
 
 			@Override
 			public void onCompleted() {
 				logger.info("Client completed");
+				channel.shutdownNow();
 			}
 		};
 
@@ -220,7 +234,11 @@ final class GrpcUtils {
 			}
 		}).doOnComplete(() -> {
 			requestObserver.onCompleted();
-		}).subscribe();
+		}).doOnError(e -> {
+			e.printStackTrace();
+			channel.shutdownNow();
+		})
+		.subscribe();
 
 		try {
 			return resultRef.poll(Integer.MAX_VALUE, TimeUnit.MILLISECONDS);
@@ -229,6 +247,9 @@ final class GrpcUtils {
 			Thread.currentThread().interrupt();
 			throw new IllegalStateException(ie);
 		}
+		finally {
+			channel.shutdownNow();
+		}
 	}
 
 	private static ClientResponseObserver<GrpcSpringMessage, GrpcSpringMessage> clientResponseObserver(Flux<Message<byte[]>> inputStream, Many<Message<byte[]>> sink) {

spring-cloud-function-adapters/spring-cloud-function-grpc/src/main/java/org/springframework/cloud/function/grpc/MessageHandlingHelper.java

@@ -185,18 +185,26 @@ public class MessageHandlingHelper<T extends GeneratedMessageV3> implements Smar
 			if (function.isOutputTypePublisher()) {
 				return this.biStreamReactive(responseObserver, serverCallStreamObserver, grpcMessageType);
 			}
-			throw new UnsupportedOperationException("The bi-directional streaming is "
+			UnsupportedOperationException ex = new UnsupportedOperationException("The bi-directional streaming is "
 					+ "not supported for functions that accept Publisher but return non-Publisher: "
 					+ function);
+//			responseObserver.onError(Status.UNKNOWN.withDescription("Error handling request")
+//					.withCause(ex).asException());
+			responseObserver.onCompleted();
+			throw ex;
 		}
 		else {
 			if (!function.isOutputTypePublisher()) {
 				return this.biStreamImperative(responseObserver, serverCallStreamObserver, wasReady);
 			}
-			throw new UnsupportedOperationException("The bidirection streaming is "
+
+			UnsupportedOperationException ex = new UnsupportedOperationException("The bidirection streaming is "
 					+ "not supported for functions that accept non-Publisher but return Publisher: "
 					+ function);
-
+//			responseObserver.onError(Status.UNKNOWN.withDescription("Error handling request")
+//					.withCause(ex).asException());
+			responseObserver.onCompleted();
+			throw ex;
 		}
 	}
 

spring-cloud-function-adapters/spring-cloud-function-grpc/src/test/java/org/springframework/cloud/function/grpc/GrpcInteractionTests.java

@@ -39,7 +39,6 @@ import org.springframework.util.MimeTypeUtils;
 import org.springframework.util.SocketUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.junit.jupiter.api.Assertions.fail;
 
 /**
  *
@@ -225,13 +224,7 @@ public class GrpcInteractionTests {
 			Flux<Message<byte[]>> clientResponseObserver =
 					GrpcUtils.biStreaming("localhost", port, Flux.fromIterable(messages));
 
-			try {
+			assertThat(clientResponseObserver.collectList().block(Duration.ofSeconds(2))).isEmpty();
-				clientResponseObserver.collectList().block(Duration.ofSeconds(1));
-				fail();
-			}
-			catch (Exception e) {
-				// TODO: handle exception
-			}
 		}
 	}
 
@@ -256,13 +249,7 @@ public class GrpcInteractionTests {
 			Flux<Message<byte[]>> clientResponseObserver =
 					GrpcUtils.biStreaming("localhost", port, Flux.fromIterable(messages));
 
-			try {
+			assertThat(clientResponseObserver.collectList().block(Duration.ofSeconds(2))).isEmpty();
-				clientResponseObserver.collectList().block(Duration.ofSeconds(1));
-				fail();
-			}
-			catch (Exception e) {
-				// TODO: handle exception
-			}
 		}
 	}