examples: deadline (#2494)

* Deadliner service

* Works.

* Uses helloworld.proto.

* Style fix

* Comments

* Uses Echo service and adds streaming example.

* Addresses the comments.

* Adds an error.

* Addresses PR comments.

* Removes port parameter from a function.

examples/features/deadline/client/main.go

@@ -0,0 +1,95 @@
+/*
+ *
+ * Copyright 2018 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.
+ *
+ */
+
+// Binary client is an example client.
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"log"
+	"time"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	pb "google.golang.org/grpc/examples/features/proto/echo"
+	"google.golang.org/grpc/status"
+)
+
+func unaryCall(c pb.EchoClient, requestID int, message string, want codes.Code) {
+	// Creates a context with a one second deadline for the RPC.
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+
+	req := &pb.EchoRequest{Message: message}
+
+	_, err := c.UnaryEcho(ctx, req)
+	got := status.Code(err)
+	fmt.Printf("[%v] wanted = %v, got = %v\n", requestID, want, got)
+}
+
+func streamingCall(c pb.EchoClient, requestID int, message string, want codes.Code) {
+	// Creates a context with a one second deadline for the RPC.
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+
+	stream, err := c.BidirectionalStreamingEcho(ctx)
+	if err != nil {
+		log.Printf("Stream err: %v", err)
+		return
+	}
+
+	err = stream.Send(&pb.EchoRequest{Message: message})
+	if err != nil {
+		log.Printf("Send error: %v", err)
+		return
+	}
+
+	_, err = stream.Recv()
+
+	got := status.Code(err)
+	fmt.Printf("[%v] wanted = %v, got = %v\n", requestID, want, got)
+}
+
+func main() {
+	port := flag.Int("port", 50052, "port number")
+	flag.Parse()
+
+	target := fmt.Sprintf("localhost:%v", *port)
+	conn, err := grpc.Dial(target, grpc.WithInsecure())
+	if err != nil {
+		log.Fatalf("did not connect: %v", err)
+	}
+	defer conn.Close()
+
+	c := pb.NewEchoClient(conn)
+
+	// A successful request
+	unaryCall(c, 1, "world", codes.OK)
+	// Exceeds deadline
+	unaryCall(c, 2, "delay", codes.DeadlineExceeded)
+	// A successful request with propagated deadline
+	unaryCall(c, 3, "[propagate me]world", codes.OK)
+	// Exceeds propagated deadline
+	unaryCall(c, 4, "[propagate me][propagate me]world", codes.DeadlineExceeded)
+	// Receives a response from the stream successfully.
+	streamingCall(c, 5, "[propagate me]world", codes.OK)
+	// Exceeds propagated deadline before receiving a response
+	streamingCall(c, 6, "[propagate me][propagate me]world", codes.DeadlineExceeded)
+}

examples/features/deadline/server/main.go

@@ -0,0 +1,128 @@
+/*
+ *
+ * Copyright 2018 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.
+ *
+ */
+
+// Binary server is an example server.
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"strings"
+	"time"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	pb "google.golang.org/grpc/examples/features/proto/echo"
+	"google.golang.org/grpc/status"
+)
+
+var port = flag.Int("port", 50052, "port number")
+
+// server is used to implement EchoServer.
+type server struct {
+	client pb.EchoClient
+	cc     *grpc.ClientConn
+}
+
+func (s *server) UnaryEcho(ctx context.Context, req *pb.EchoRequest) (*pb.EchoResponse, error) {
+	message := req.Message
+	if strings.HasPrefix(message, "[propagate me]") {
+		time.Sleep(800 * time.Millisecond)
+		message = strings.TrimPrefix(message, "[propagate me]")
+		return s.client.UnaryEcho(ctx, &pb.EchoRequest{Message: message})
+	}
+
+	if message == "delay" {
+		time.Sleep(1500 * time.Millisecond)
+	}
+
+	return &pb.EchoResponse{Message: req.Message}, nil
+}
+
+func (s *server) ServerStreamingEcho(req *pb.EchoRequest, stream pb.Echo_ServerStreamingEchoServer) error {
+	return status.Error(codes.Unimplemented, "RPC unimplemented")
+}
+
+func (s *server) ClientStreamingEcho(stream pb.Echo_ClientStreamingEchoServer) error {
+	return status.Error(codes.Unimplemented, "RPC unimplemented")
+}
+
+func (s *server) BidirectionalStreamingEcho(stream pb.Echo_BidirectionalStreamingEchoServer) error {
+	for {
+		req, err := stream.Recv()
+		if err == io.EOF {
+			return status.Error(codes.InvalidArgument, "request message not received")
+		}
+		if err != nil {
+			return err
+		}
+
+		message := req.Message
+		if strings.HasPrefix(message, "[propagate me]") {
+			time.Sleep(800 * time.Millisecond)
+			message = strings.TrimPrefix(message, "[propagate me]")
+			res, err := s.client.UnaryEcho(stream.Context(), &pb.EchoRequest{Message: message})
+			if err != nil {
+				return err
+			}
+			stream.Send(res)
+		}
+
+		if message == "delay" {
+			time.Sleep(1500 * time.Millisecond)
+		}
+		stream.Send(&pb.EchoResponse{Message: message})
+	}
+}
+
+func (s *server) Close() {
+	s.cc.Close()
+}
+
+func newEchoServer() *server {
+	target := fmt.Sprintf("localhost:%v", *port)
+	cc, err := grpc.Dial(target, grpc.WithInsecure())
+	if err != nil {
+		log.Fatalf("did not connect: %v", err)
+	}
+	return &server{client: pb.NewEchoClient(cc), cc: cc}
+}
+
+func main() {
+	flag.Parse()
+
+	address := fmt.Sprintf(":%v", *port)
+	lis, err := net.Listen("tcp", address)
+	if err != nil {
+		log.Fatalf("failed to listen: %v", err)
+	}
+
+	echoServer := newEchoServer()
+	defer echoServer.Close()
+
+	grpcServer := grpc.NewServer()
+	pb.RegisterEchoServer(grpcServer, echoServer)
+
+	if err := grpcServer.Serve(lis); err != nil {
+		log.Fatalf("failed to serve: %v", err)
+	}
+}