distribute: Make server work with multiple remote disks

This change initializes rpc servers associated with disks that are
local. It makes object layer initialization on demand, namely on the
first request to the object layer.

Also adds lock RPC service vendorized minio/dsync

cmd/rpc-server.go

@@ -1,7 +1,25 @@
-package cmd
+/*
+ * Minio Cloud Storage, (C) 2016 Minio, 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 main
 
 import (
 	"net/rpc"
+	"path"
+	"strings"
 
 	router "github.com/gorilla/mux"
 )
@@ -10,6 +28,7 @@ import (
 // disk over a network.
 type storageServer struct {
 	storage StorageAPI
+	path    string
 }
 
 /// Volume operations handlers
@@ -103,22 +122,50 @@ func (s *storageServer) RenameFileHandler(arg *RenameFileArgs, reply *GenericRep
 }
 
 // Initialize new storage rpc.
-func newRPCServer(exportPath string) (*storageServer, error) {
+func newRPCServer(serverConfig serverCmdConfig) (servers []*storageServer, err error) {
 	// Initialize posix storage API.
-	storage, err := newPosix(exportPath)
-	if err != nil && err != errDiskNotFound {
-		return nil, err
+	exports := serverConfig.disks
+	ignoredExports := serverConfig.ignoredDisks
+
+	// Save ignored disks in a map
+	skipDisks := make(map[string]bool)
+	for _, ignoredExport := range ignoredExports {
+		skipDisks[ignoredExport] = true
 	}
-	return &storageServer{
-		storage: storage,
-	}, nil
+	for _, export := range exports {
+		if skipDisks[export] {
+			continue
+		}
+		// e.g server:/mnt/disk1
+		if isLocalStorage(export) {
+			if idx := strings.LastIndex(export, ":"); idx != -1 {
+				export = export[idx+1:]
+			}
+			var storage StorageAPI
+			storage, err = newPosix(export)
+			if err != nil && err != errDiskNotFound {
+				return nil, err
+			}
+			if idx := strings.LastIndex(export, ":"); idx != -1 {
+				export = export[idx+1:]
+			}
+			servers = append(servers, &storageServer{
+				storage: storage,
+				path:    export,
+			})
+		}
+	}
+	return servers, err
 }
 
 // registerStorageRPCRouter - register storage rpc router.
-func registerStorageRPCRouter(mux *router.Router, stServer *storageServer) {
+func registerStorageRPCRouters(mux *router.Router, stServers []*storageServer) {
 	storageRPCServer := rpc.NewServer()
-	storageRPCServer.RegisterName("Storage", stServer)
-	storageRouter := mux.NewRoute().PathPrefix(reservedBucket).Subrouter()
-	// Add minio storage routes.
-	storageRouter.Path("/storage").Handler(storageRPCServer)
+	// Create a unique route for each disk exported from this node.
+	for _, stServer := range stServers {
+		storageRPCServer.RegisterName("Storage", stServer)
+		// Add minio storage routes.
+		storageRouter := mux.PathPrefix(reservedBucket).Subrouter()
+		storageRouter.Path(path.Join("/storage", stServer.path)).Handler(storageRPCServer)
+	}
 }