| /* |
| * |
| * 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 wait_for_ready is an example for "wait for ready". |
| package main |
| |
| import ( |
| "context" |
| "fmt" |
| "log" |
| "net" |
| "sync" |
| "time" |
| |
| "google.golang.org/grpc" |
| "google.golang.org/grpc/codes" |
| pb "google.golang.org/grpc/examples/features/proto/echo" |
| "google.golang.org/grpc/status" |
| ) |
| |
| // server is used to implement EchoServer. |
| type server struct{} |
| |
| func (s *server) UnaryEcho(ctx context.Context, req *pb.EchoRequest) (*pb.EchoResponse, error) { |
| 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 { |
| return status.Error(codes.Unimplemented, "RPC unimplemented") |
| } |
| |
| // serve starts listening with a 2 seconds delay. |
| func serve() { |
| lis, err := net.Listen("tcp", ":50053") |
| if err != nil { |
| log.Fatalf("failed to listen: %v", err) |
| } |
| s := grpc.NewServer() |
| pb.RegisterEchoServer(s, &server{}) |
| |
| if err := s.Serve(lis); err != nil { |
| log.Fatalf("failed to serve: %v", err) |
| } |
| } |
| |
| func main() { |
| conn, err := grpc.Dial("localhost:50053", grpc.WithInsecure()) |
| if err != nil { |
| log.Fatalf("did not connect: %v", err) |
| } |
| defer conn.Close() |
| |
| c := pb.NewEchoClient(conn) |
| |
| var wg sync.WaitGroup |
| wg.Add(3) |
| |
| // "Wait for ready" is not enabled, returns error with code "Unavailable". |
| go func() { |
| defer wg.Done() |
| |
| ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second) |
| defer cancel() |
| |
| _, err := c.UnaryEcho(ctx, &pb.EchoRequest{Message: "Hi!"}) |
| |
| got := status.Code(err) |
| fmt.Printf("[1] wanted = %v, got = %v\n", codes.Unavailable, got) |
| }() |
| |
| // "Wait for ready" is enabled, returns nil error. |
| go func() { |
| defer wg.Done() |
| |
| ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second) |
| defer cancel() |
| |
| _, err := c.UnaryEcho(ctx, &pb.EchoRequest{Message: "Hi!"}, grpc.WaitForReady(true)) |
| |
| got := status.Code(err) |
| fmt.Printf("[2] wanted = %v, got = %v\n", codes.OK, got) |
| }() |
| |
| // "Wait for ready" is enabled but exceeds the deadline before server starts listening, |
| // returns error with code "DeadlineExceeded". |
| go func() { |
| defer wg.Done() |
| |
| ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second) |
| defer cancel() |
| |
| _, err := c.UnaryEcho(ctx, &pb.EchoRequest{Message: "Hi!"}, grpc.WaitForReady(true)) |
| |
| got := status.Code(err) |
| fmt.Printf("[3] wanted = %v, got = %v\n", codes.DeadlineExceeded, got) |
| }() |
| |
| time.Sleep(2 * time.Second) |
| go serve() |
| |
| wg.Wait() |
| } |