snapshot of https://github.com/grpc/grpc-go.git (master, 2026-09-15; blobs > 131072B omitted)

examples/features/keepalive/server/main.go

@@ -0,0 +1,76 @@
+/*
+ *
+ * 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 demonstrates how to enforce keepalive settings and manage idle
+// connections to maintain active client connections.
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"log"
+	"net"
+	"time"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/keepalive"
+
+	pb "google.golang.org/grpc/examples/features/proto/echo"
+)
+
+var port = flag.Int("port", 50052, "port number")
+
+var kaep = keepalive.EnforcementPolicy{
+	MinTime:             5 * time.Second, // If a client pings more than once every 5 seconds, terminate the connection
+	PermitWithoutStream: true,            // Allow pings even when there are no active streams
+}
+
+var kasp = keepalive.ServerParameters{
+	MaxConnectionIdle:     15 * time.Second, // If a client is idle for 15 seconds, send a GOAWAY
+	MaxConnectionAge:      30 * time.Second, // If any connection is alive for more than 30 seconds, send a GOAWAY
+	MaxConnectionAgeGrace: 5 * time.Second,  // Allow 5 seconds for pending RPCs to complete before forcibly closing connections
+	Time:                  5 * time.Second,  // Ping the client if it is idle for 5 seconds to ensure the connection is still active
+	Timeout:               1 * time.Second,  // Wait 1 second for the ping ack before assuming the connection is dead
+}
+
+// server implements EchoServer.
+type server struct {
+	pb.UnimplementedEchoServer
+}
+
+func (s *server) UnaryEcho(_ context.Context, req *pb.EchoRequest) (*pb.EchoResponse, error) {
+	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)
+	}
+
+	s := grpc.NewServer(grpc.KeepaliveEnforcementPolicy(kaep), grpc.KeepaliveParams(kasp))
+	pb.RegisterEchoServer(s, &server{})
+
+	if err := s.Serve(lis); err != nil {
+		log.Fatalf("failed to serve: %v", err)
+	}
+}