etcdserver: add maintain service to support defrag

etcdserver/api/v3rpc/grpc.go

@@ -37,5 +37,6 @@ func Server(s *etcdserver.EtcdServer, tls *transport.TLSInfo) (*grpc.Server, err
 	pb.RegisterLeaseServer(grpcServer, NewLeaseServer(s))
 	pb.RegisterClusterServer(grpcServer, NewClusterServer(s))
 	pb.RegisterAuthServer(grpcServer, NewAuthServer(s))
+	pb.RegisterMaintenanceServer(grpcServer, NewMaintenanceServer(s))
 	return grpcServer, nil
 }

etcdserver/api/v3rpc/maintenance.go

@@ -0,0 +1,45 @@
+// Copyright 2016 CoreOS, Inc.
+//
+// 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.
+
+package v3rpc
+
+import (
+	"github.com/coreos/etcd/Godeps/_workspace/src/golang.org/x/net/context"
+	"github.com/coreos/etcd/etcdserver"
+	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
+	"github.com/coreos/etcd/storage/backend"
+)
+
+type BackendGetter interface {
+	Backend() backend.Backend
+}
+
+type maintenanceServer struct {
+	bg BackendGetter
+}
+
+func NewMaintenanceServer(s *etcdserver.EtcdServer) pb.MaintenanceServer {
+	return &maintenanceServer{bg: s}
+}
+
+func (ms *maintenanceServer) Defragment(ctx context.Context, sr *pb.DefragmentRequest) (*pb.DefragmentResponse, error) {
+	plog.Noticef("starting to defragment the storage backend...")
+	err := ms.bg.Backend().Defrag()
+	if err != nil {
+		plog.Errorf("failed to deframent the storage backend (%v)", err)
+		return nil, err
+	}
+	plog.Noticef("finished defragmenting the storage backend")
+	return &pb.DefragmentResponse{}, nil
+}