master server graceful stop (#3797)

weed/command/master.go

@@ -2,6 +2,7 @@ package command
 
 import (
 	"fmt"
+	hashicorpRaft "github.com/hashicorp/raft"
 	"net/http"
 	"os"
 	"path"
@@ -253,6 +254,13 @@ func startMaster(masterOption MasterOptions, masterWhiteList []string) {
 		go httpS.Serve(masterListener)
 	}
 
+	grace.OnInterrupt(ms.Shutdown)
+	grace.OnInterrupt(grpcS.GracefulStop)
+	grace.OnReload(func() {
+		if ms.Topo.HashicorpRaft != nil && ms.Topo.HashicorpRaft.State() == hashicorpRaft.Leader {
+			ms.Topo.HashicorpRaft.LeadershipTransfer()
+		}
+	})
 	select {}
 }