Add basic controller code, initiating json rpc connection getting list of disks and memstats for now.

commands.go

@@ -4,6 +4,7 @@ import (
 	"os/user"
 
 	"github.com/minio/cli"
+	"github.com/minio/minio/pkg/controller"
 	"github.com/minio/minio/pkg/server"
 	"github.com/minio/minio/pkg/server/api"
 )
@@ -41,8 +42,11 @@ USAGE:
   minio {{.Name}}
 
 EXAMPLES:
-  1. Start in controller mode
-      $ minio {{.Name}}
+  1. Get disks from controller
+      $ minio {{.Name}} disks http://localhost:9001/rpc
+
+  2. Get memstats from controller
+      $ minio {{.Name}} mem http://localhost:9001/rpc
 
 `,
 }
@@ -79,4 +83,21 @@ func runController(c *cli.Context) {
 	if err != nil {
 		Fatalf("Unable to determine current user. Reason: %s\n", err)
 	}
+	if len(c.Args()) != 2 || c.Args().First() == "help" {
+		cli.ShowCommandHelpAndExit(c, "controller", 1) // last argument is exit code
+	}
+	switch c.Args().First() {
+	case "disks":
+		disks, err := controller.GetDisks(c.Args().Tail().First())
+		if err != nil {
+			Fatalln(err)
+		}
+		Println(disks)
+	case "mem":
+		memstats, err := controller.GetMemStats(c.Args().Tail().First())
+		if err != nil {
+			Fatalln(err)
+		}
+		Println(string(memstats))
+	}
 }

console.go

@@ -28,6 +28,7 @@ type logLevel int
 
 const (
 	levelUnknown logLevel = iota
+	levelPrint
 	levelDebug
 	levelInfo
 	levelError
@@ -64,6 +65,13 @@ var (
 	Debugln = func(a ...interface{}) { privatePrintln(levelDebug, a...) }
 	// Debugf prints a debug message with formatting
 	Debugf = func(f string, a ...interface{}) { privatePrintf(levelDebug, f, a...) }
+
+	// Print prints a debug message
+	Print = func(a ...interface{}) { privatePrint(levelPrint, a...) }
+	// Println prints a debug message with a new line
+	Println = func(a ...interface{}) { privatePrintln(levelPrint, a...) }
+	// Printf prints a debug message with formatting
+	Printf = func(f string, a ...interface{}) { privatePrintf(levelPrint, f, a...) }
 )
 
 var (

pkg/controller/client.go

@@ -0,0 +1,72 @@
+/*
+ * Minimalist Object Storage, (C) 2015 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 controller
+
+import (
+	"encoding/json"
+	"net/http"
+
+	jsonrpc "github.com/gorilla/rpc/v2/json"
+	"github.com/minio/minio/pkg/iodine"
+	"github.com/minio/minio/pkg/server/rpc"
+)
+
+// GetDisks get disks info of the server at given url
+func GetDisks(url string) ([]string, error) {
+	op := RPCOps{
+		Method:  "DiskInfo.Get",
+		Request: rpc.Args{Request: ""},
+	}
+	req, err := NewRequest(url, op, http.DefaultTransport)
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	resp, err := req.Do()
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	defer resp.Body.Close()
+	var reply rpc.DiskInfoReply
+	if err := jsonrpc.DecodeClientResponse(resp.Body, &reply); err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	return reply.Disks, nil
+}
+
+// GetMemStats get system info of the server at given url
+func GetMemStats(url string) ([]byte, error) {
+	op := RPCOps{
+		Method:  "SysInfo.Get",
+		Request: rpc.Args{Request: ""},
+	}
+	req, err := NewRequest(url, op, http.DefaultTransport)
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	resp, err := req.Do()
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	defer resp.Body.Close()
+	var reply rpc.SysInfoReply
+	if err := jsonrpc.DecodeClientResponse(resp.Body, &reply); err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	return json.MarshalIndent(reply, "", "\t")
+}
+
+// Add more functions here for many replies

pkg/controller/rpc.go

@@ -0,0 +1,66 @@
+/*
+ * Minimalist Object Storage, (C) 2015 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 controller
+
+import (
+	"bytes"
+	"net/http"
+
+	"github.com/gorilla/rpc/v2/json"
+	"github.com/minio/minio/pkg/iodine"
+)
+
+// RPCOps RPC operation
+type RPCOps struct {
+	Method  string
+	Request interface{}
+}
+
+// RPCRequest rpc client request
+type RPCRequest struct {
+	req       *http.Request
+	transport http.RoundTripper
+}
+
+// NewRequest initiate a new client RPC request
+func NewRequest(url string, op RPCOps, transport http.RoundTripper) (*RPCRequest, error) {
+	params, err := json.EncodeClientRequest(op.Method, op.Request)
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	req, err := http.NewRequest("POST", url, bytes.NewReader(params))
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	rpcReq := &RPCRequest{}
+	rpcReq.req = req
+	rpcReq.req.Header.Set("Content-Type", "application/json")
+	if transport == nil {
+		transport = http.DefaultTransport
+	}
+	rpcReq.transport = transport
+	return rpcReq, nil
+}
+
+// Do - make a http connection
+func (r RPCRequest) Do() (*http.Response, error) {
+	resp, err := r.transport.RoundTrip(r.req)
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	return resp, nil
+}

pkg/server/router.go

@@ -24,11 +24,6 @@ import (
 	"github.com/minio/minio/pkg/server/rpc"
 )
 
-// Get api
-func getAPI() api.Minio {
-	return api.New()
-}
-
 // registerAPI - register all the object API handlers to their respective paths
 func registerAPI(mux *router.Router, a api.Minio) http.Handler {
 	mux.HandleFunc("/", a.ListBucketsHandler).Methods("GET")
@@ -107,7 +102,7 @@ func registerRPC(mux *router.Router, s *rpc.Server) http.Handler {
 // getAPIHandler api handler
 func getAPIHandler(conf api.Config) (http.Handler, api.Minio) {
 	mux := router.NewRouter()
-	minioAPI := getAPI()
+	minioAPI := api.New()
 	apiHandler := registerAPI(mux, minioAPI)
 	apiHandler = registerCustomMiddleware(apiHandler, conf)
 	return apiHandler, minioAPI