grpc-go/examples/features/retry/server/main.go

94 lines
2.2 KiB
Go

/*
*
* Copyright 2019 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"
"log"
"net"
"sync"
"google.golang.org/grpc"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/status"
pb "google.golang.org/grpc/examples/features/proto/echo"
)
var port = flag.Int("port", 50052, "port number")
type failingServer struct {
pb.UnimplementedEchoServer
mu sync.Mutex
reqCounter uint
reqModulo uint
}
// this method will fail reqModulo - 1 times RPCs and return status code Unavailable,
// and succeeded RPC on reqModulo times.
func (s *failingServer) maybeFailRequest() error {
s.mu.Lock()
defer s.mu.Unlock()
s.reqCounter++
if (s.reqModulo > 0) && (s.reqCounter%s.reqModulo == 0) {
return nil
}
return status.Errorf(codes.Unavailable, "maybeFailRequest: failing it")
}
func (s *failingServer) UnaryEcho(ctx context.Context, req *pb.EchoRequest) (*pb.EchoResponse, error) {
if err := s.maybeFailRequest(); err != nil {
log.Println("request failed count:", s.reqCounter)
return nil, err
}
log.Println("request succeeded count:", s.reqCounter)
return &pb.EchoResponse{Message: req.Message}, nil
}
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)
}
fmt.Println("listen on address", address)
s := grpc.NewServer()
// Configure server to pass every fourth RPC;
// client is configured to make four attempts.
failingservice := &failingServer{
reqCounter: 0,
reqModulo: 4,
}
pb.RegisterEchoServer(s, failingservice)
if err := s.Serve(lis); err != nil {
log.Fatalf("failed to serve: %v", err)
}
}