embed: use gRPC server GracefulStop method

Fix #7322.

Signed-off-by: Gyu-Ho Lee <gyuhox@gmail.com>

embed/etcd.go

@@ -22,6 +22,8 @@ import (
 	"path/filepath"
 	"sync"
 
+	"google.golang.org/grpc"
+
 	"github.com/coreos/etcd/etcdserver"
 	"github.com/coreos/etcd/etcdserver/api/v2http"
 	"github.com/coreos/etcd/pkg/cors"
@@ -137,6 +139,11 @@ func StartEtcd(inCfg *Config) (e *Etcd, err error) {
 	if err = e.serve(); err != nil {
 		return
 	}
+	e.Server.Cfg.OnShutdown = func() {
+		for _, sctx := range e.sctxs {
+			(<-sctx.stopGRPCc)()
+		}
+	}
 	return
 }
 
@@ -343,6 +350,10 @@ func (e *Etcd) serve() (err error) {
 }
 
 func (e *Etcd) errHandler(err error) {
+	if transport.IsClosedConnError(err) || err == grpc.ErrServerStopped {
+		plog.Warningf("server stopped with %q", err.Error())
+		return
+	}
 	select {
 	case <-e.stopc:
 		return

embed/serve.go

@@ -52,11 +52,12 @@ type serveCtx struct {
 
 	userHandlers    map[string]http.Handler
 	serviceRegister func(*grpc.Server)
+	stopGRPCc       chan func()
 }
 
 func newServeCtx() *serveCtx {
 	ctx, cancel := context.WithCancel(context.Background())
-	return &serveCtx{ctx: ctx, cancel: cancel, userHandlers: make(map[string]http.Handler)}
+	return &serveCtx{ctx: ctx, cancel: cancel, userHandlers: make(map[string]http.Handler), stopGRPCc: make(chan func())}
 }
 
 // serve accepts incoming connections on the listener l,
@@ -74,6 +75,12 @@ func (sctx *serveCtx) serve(s *etcdserver.EtcdServer, tlscfg *tls.Config, handle
 
 	if sctx.insecure {
 		gs := v3rpc.Server(s, nil)
+		sctx.stopGRPCc <- func() {
+			plog.Warning("gracefully stopping gRPC server")
+			gs.GracefulStop()
+			plog.Warning("gracefully stopped gRPC server")
+		}
+		close(sctx.stopGRPCc)
 		v3electionpb.RegisterElectionServer(gs, servElection)
 		v3lockpb.RegisterLockServer(gs, servLock)
 		if sctx.serviceRegister != nil {
@@ -103,6 +110,12 @@ func (sctx *serveCtx) serve(s *etcdserver.EtcdServer, tlscfg *tls.Config, handle
 
 	if sctx.secure {
 		gs := v3rpc.Server(s, tlscfg)
+		sctx.stopGRPCc <- func() {
+			plog.Warning("gracefully stopping gRPC server")
+			gs.GracefulStop()
+			plog.Warning("gracefully stopped gRPC server")
+		}
+		close(sctx.stopGRPCc)
 		v3electionpb.RegisterElectionServer(gs, servElection)
 		v3lockpb.RegisterLockServer(gs, servLock)
 		if sctx.serviceRegister != nil {