refactor: change masters from a slice to a map

weed/server/filer_grpc_server.go

@@ -393,7 +393,7 @@ func (fs *FilerServer) GetFilerConfiguration(ctx context.Context, req *filer_pb.
 	clusterId, _ := fs.filer.Store.KvGet(context.Background(), []byte("clusterId"))
 
 	t := &filer_pb.GetFilerConfigurationResponse{
-		Masters:            pb.ToAddressStrings(fs.option.Masters),
+		Masters:            pb.ToAddressStringsFromMap(fs.option.Masters),
 		Collection:         fs.option.Collection,
 		Replication:        fs.option.DefaultReplication,
 		MaxMb:              uint32(fs.option.MaxMB),

weed/server/filer_server.go

@@ -48,7 +48,7 @@ import (
 )
 
 type FilerOption struct {
-	Masters               []pb.ServerAddress
+	Masters               map[string]pb.ServerAddress
 	Collection            string
 	DefaultReplication    string
 	DisableDirListing     bool

weed/server/master_server.go

@@ -75,7 +75,7 @@ type MasterServer struct {
 	Cluster *cluster.Cluster
 }
 
-func NewMasterServer(r *mux.Router, option *MasterOption, peers []pb.ServerAddress) *MasterServer {
+func NewMasterServer(r *mux.Router, option *MasterOption, peers map[string]pb.ServerAddress) *MasterServer {
 
 	v := util.GetViper()
 	signingKey := v.GetString("jwt.signing.key")