clean up the codes

command.go

@@ -10,16 +10,15 @@ import (
 	"encoding/json"
 	)
 
-
 // A command represents an action to be taken on the replicated state machine.
 type Command interface {
 	CommandName() string
 	Apply(server *raft.Server) ([]byte, error)
-	GeneratePath() string
-	Type() string
+	GeneratePath() string // Gererate a path for http request
+	Type() string // http request type
 	GetValue() string
 	GetKey() string
-	Sensitive() bool
+	Sensitive() bool // Sensitive to the stateMachine
 }
 
 // Set command
@@ -39,10 +38,12 @@ func (c *SetCommand) Apply(server *raft.Server) ([]byte, error) {
 	return json.Marshal(res)
 }
 
+// Get the path for http request
 func (c *SetCommand) GeneratePath() string {
 	return "set/" + c.Key
 }
 
+// Get the type for http request
 func (c *SetCommand) Type() string {
 	return "POST"
 }
@@ -96,6 +97,7 @@ func (c *GetCommand) Sensitive() bool {
 	return false
 }
 
+
 // Delete command
 type DeleteCommand struct {
 	Key string `json:"key"`
@@ -146,8 +148,10 @@ func (c *WatchCommand) CommandName() string {
 func (c *WatchCommand) Apply(server *raft.Server) ([]byte, error){
 	ch := make(chan Response)
 
+	// add to the watchers list
 	w.add(c.Key, ch)	
 
+	// wait for the notification for any changing
 	res := <- ch
 
 	return json.Marshal(res)
@@ -173,6 +177,7 @@ func (c *WatchCommand) Sensitive() bool {
 	return false
 }
 
+
 // JoinCommand
 type JoinCommand struct {
 	Name string `json:"name"`
@@ -184,5 +189,6 @@ func (c *JoinCommand) CommandName() string {
 
 func (c *JoinCommand) Apply(server *raft.Server) ([]byte, error) {
 	err := server.AddPeer(c.Name)
+	// no result will be returned
 	return nil, err
 }

handlers.go

@@ -9,12 +9,12 @@ import (
 	"bytes"
 	)
 
+
 //--------------------------------------
 // HTTP Handlers
 //--------------------------------------
 
-
-
+// Get all the current logs
 func GetLogHttpHandler(w http.ResponseWriter, req *http.Request) {
 	debug("[recv] GET http://%v/log", server.Name())
 	w.Header().Set("Content-Type", "application/json")
@@ -33,6 +33,7 @@ func VoteHttpHandler(w http.ResponseWriter, req *http.Request) {
 			return
 		}
 	}
+	warn("[vote] ERROR: %v", err)
 	w.WriteHeader(http.StatusInternalServerError)
 }
 
@@ -41,19 +42,16 @@ func AppendEntriesHttpHandler(w http.ResponseWriter, req *http.Request) {
 	err := decodeJsonRequest(req, aereq)
 	if err == nil {
 		debug("[recv] POST http://%s/log/append [%d]", server.Name(), len(aereq.Entries))
-		debug("My role is %s", server.State())
 		if resp, _ := server.AppendEntries(aereq); resp != nil {
-			debug("write back success")
 			w.WriteHeader(http.StatusOK)
 			json.NewEncoder(w).Encode(resp)
 			if !resp.Success {
-				fmt.Println("append error")
+				debug("[Append Entry] Step back")
 			}
 			return
 		}
 	}
 	warn("[append] ERROR: %v", err)
-	debug("write back")
 	w.WriteHeader(http.StatusInternalServerError)
 }
 
@@ -96,6 +94,7 @@ func SetHttpHandler(w http.ResponseWriter, req *http.Request) {
 	debug("[recv] POST http://%v/set/%s", server.Name(), key)
 
 	content, err := ioutil.ReadAll(req.Body)
+
 	if err != nil {
 		warn("raftd: Unable to read: %v", err)
 		w.WriteHeader(http.StatusInternalServerError)
@@ -107,7 +106,6 @@ func SetHttpHandler(w http.ResponseWriter, req *http.Request) {
 	command.Value = string(content)
 
 	Dispatch(server, command, w)
-
 }
 
 func GetHttpHandler(w http.ResponseWriter, req *http.Request) {
@@ -131,7 +129,6 @@ func DeleteHttpHandler(w http.ResponseWriter, req *http.Request) {
 	command.Key = key
 
 	Dispatch(server, command, w)
-
 }
 
 
@@ -151,91 +148,94 @@ func Dispatch(server *raft.Server, command Command, w http.ResponseWriter) {
 	var body []byte
 	var err error
 
+	debug("Dispatch command")
 
-	fmt.Println("dispatch")
-	// unlikely to fail twice
-	for {
-		// i am the leader, i will take care of the command
-		if server.State() == "leader" {
-			if command.Sensitive() {
-				if body, err = server.Do(command); err != nil {
-					warn("raftd: Unable to write file: %v", err)
-					w.WriteHeader(http.StatusInternalServerError)
-					return
-				} else {
-				// good to go
-					w.WriteHeader(http.StatusOK)
-					w.Write(body)
-					return
-				}
-			} else {
-				fmt.Println("non-sensitive")
-				if body, err = command.Apply(server); err != nil {
-					warn("raftd: Unable to write file: %v", err)
-					w.WriteHeader(http.StatusInternalServerError)
-					return
-				} else {
-				// good to go
-					w.WriteHeader(http.StatusOK)
-					w.Write(body)
-					return
-				}
-			}
-
-		// redirect the command to the current leader
-		} else {
-			leaderName := server.Leader()
-
-			if leaderName =="" {
-				// no luckey, during the voting process
+	// i am the leader, i will take care of the command
+	if server.State() == "leader" {
+		// if the command will change the state of the state machine
+		// the command need to append to the log entry
+		if command.Sensitive() {
+			if body, err = server.Do(command); err != nil {
+				warn("raftd: Unable to write file: %v", err)
 				w.WriteHeader(http.StatusInternalServerError)
 				return
-			} 
-
-			fmt.Println("forward to ", leaderName)
-
-			path := command.GeneratePath()
-
-			if command.Type() == "POST" {
-				debug("[send] POST http://%v/%s", leaderName, path)
-
-				reader := bytes.NewReader([]byte(command.GetValue()))
-
-				reps, _ := http.Post(fmt.Sprintf("http://%v/%s", 
-					leaderName, command.GeneratePath()), "application/json", reader)
-
-				body, _ := ioutil.ReadAll(reps.Body)
-				fmt.Println(body)
+			} else {
 				// good to go
 				w.WriteHeader(http.StatusOK)
-
 				w.Write(body)
+				return
+			}
+		// for non-sentitive command, directly apply it 
+		} else {
+			if body, err = command.Apply(server); err != nil {
+				warn("raftd: Unable to write file: %v", err)
+				w.WriteHeader(http.StatusInternalServerError)
+				return
+			} else {
+				w.WriteHeader(http.StatusOK)
+				w.Write(body)
+				return
+			}
+		}
+
+	// redirect the command to the current leader
+	} else {
+		leaderName := server.Leader()
+
+		if leaderName =="" {
+			// no luckey, during the voting process
+			// the client need to catch the error and try again
+			w.WriteHeader(http.StatusInternalServerError)
+			return
+		} 
+
+		debug("forward command to %s", leaderName)
+
+		path := command.GeneratePath()
+
+		if command.Type() == "POST" {
+			debug("[send] POST http://%v/%s", leaderName, path)
+
+			reader := bytes.NewReader([]byte(command.GetValue()))
+
+			reps, _ := http.Post(fmt.Sprintf("http://%v/%s", 
+				leaderName, command.GeneratePath()), "application/json", reader)
+
+			if reps == nil {
+				w.WriteHeader(http.StatusInternalServerError)
+				return 
+			}
+
+			// forwarding
+			w.WriteHeader(reps.StatusCode)
+
+			body, _ := ioutil.ReadAll(reps.Body)
+
+			w.Write(body)
+			return 
 
 			} else if command.Type() == "GET" {
 				debug("[send] GET http://%v/%s", leaderName, path)
 
 				reps, _ := http.Get(fmt.Sprintf("http://%v/%s", 
 					leaderName, command.GeneratePath()))
-				// good to go
-				body, _ := ioutil.ReadAll(reps.Body)
-				fmt.Println(body)
 
-				w.WriteHeader(http.StatusOK)
-				
+
+				if reps == nil {
+					w.WriteHeader(http.StatusInternalServerError)
+					return 
+				}
+
+				// forwarding
+				body, _ := ioutil.ReadAll(reps.Body)
+
+				w.WriteHeader(reps.StatusCode)
+
 				w.Write(body)
 
 			} else {
-				//unsupported type
-			}
-
-			if err != nil {
-				// should check other errors
-				continue
-			} else {
-				//good to go
-				return
+			//unsupported type
 			}
 
 		}
-	}
 }

raftd.go

@@ -13,6 +13,7 @@ import (
 	"strings"
 	"os"
 	"time"
+	"strconv"
 )
 
 //------------------------------------------------------------------------------
@@ -22,12 +23,22 @@ import (
 //------------------------------------------------------------------------------
 
 var verbose bool
+var leaderHost string
+var address string
 
 func init() {
 	flag.BoolVar(&verbose, "v", false, "verbose logging")
-	flag.BoolVar(&verbose, "verbose", false, "verbose logging")
+	flag.StringVar(&leaderHost, "c", "", "join to a existing cluster")
+	flag.StringVar(&address, "a", "", "the address of the local machine")
 }
 
+const (
+	ELECTIONTIMTOUT = 3 * time.Second
+	HEARTBEATTIMEOUT = 1 * time.Second
+)
+
+
+
 //------------------------------------------------------------------------------
 //
 // Typedefs
@@ -62,9 +73,6 @@ func main() {
 	var err error
 	logger = log.New(os.Stdout, "", log.LstdFlags)
 	flag.Parse()
-	if verbose {
-		fmt.Println("Verbose logging enabled.\n")
-	}
 
 	// Setup commands.
 	raft.RegisterCommand(&JoinCommand{})
@@ -85,65 +93,54 @@ func main() {
 
 	// Read server info from file or grab it from user.
 	var info *Info = getInfo(path)
+
 	name := fmt.Sprintf("%s:%d", info.Host, info.Port)
+
 	fmt.Printf("Name: %s\n\n", name)
 	
 	t := transHandler{}
 
 	// Setup new raft server.
 	server, err = raft.NewServer(name, path, t, s, nil)
-	//server.DoHandler = DoHandler;
 	if err != nil {
 		fatal("%v", err)
 	}
 
 	server.LoadSnapshot()
 	server.Initialize()
-	fmt.Println("1 join as ", server.State(), " term ",  server.Term())
-	// Join to another server if we don't have a log.
+	server.SetElectionTimeout(ELECTIONTIMTOUT)
+	server.SetHeartbeatTimeout(HEARTBEATTIMEOUT)
+
 	if server.IsLogEmpty() {
-		var leaderHost string
-		fmt.Println("2 join as ", server.State(), " term ",  server.Term())
-		fmt.Println("This server has no log. Please enter a server in the cluster to join\nto or hit enter to initialize a cluster.");
-		fmt.Printf("Join to (host:port)> ");
-		fmt.Scanf("%s", &leaderHost)
-		fmt.Println("3 join as ", server.State(), " term ",  server.Term())
+
+		// start as a leader in a new cluster
 		if leaderHost == "" {
-			fmt.Println("init")
-			//server.SetElectionTimeout(300 * time.Millisecond)
-			//server.SetHeartbeatTimeout(100 * time.Millisecond)
-			server.SetElectionTimeout(3 * time.Second)
-			server.SetHeartbeatTimeout(1 * time.Second)
 			server.StartHeartbeatTimeout()
 			server.StartLeader()
-			// join self 
+
+			// join self as a peer
 			command := &JoinCommand{}
 			command.Name = server.Name()
-
 			server.Do(command)
+
+		// start as a fellower in a existing cluster
 		} else {
-			//server.SetElectionTimeout(300 * time.Millisecond)
-			//server.SetHeartbeatTimeout(100 * time.Millisecond)
-			server.SetElectionTimeout(3 * time.Second)
-			server.SetHeartbeatTimeout(1 * time.Second)
 			server.StartElectionTimeout()
 			server.StartFollower()
 
-			fmt.Println("4 join as ", server.State(), " term ",  server.Term())
 			Join(server, leaderHost)
 			fmt.Println("success join")
 		}
+
+	// rejoin the previous cluster
 	} else {
-		//server.SetElectionTimeout(300 * time.Millisecond)
-		//server.SetHeartbeatTimeout(100 * time.Millisecond)
-		server.SetElectionTimeout(3 * time.Second)
-		server.SetHeartbeatTimeout(1 * time.Second)
 		server.StartElectionTimeout()
 		server.StartFollower()
 	}
+
+	// open the snapshot
 	go server.Snapshot()
-	// open snapshot
-	//go server.Snapshot()
+	
 
     // internal commands
     http.HandleFunc("/join", JoinHttpHandler)
@@ -158,6 +155,7 @@ func main() {
     http.HandleFunc("/delete/", DeleteHttpHandler)
     http.HandleFunc("/watch/", WatchHttpHandler)
 
+    // listen on http port
 	log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", info.Port), nil))
 }
 
@@ -186,17 +184,24 @@ func getInfo(path string) *Info {
 	
 	// Otherwise ask user for info and write it to file.
 	} else {
-		fmt.Printf("Enter hostname: [localhost] ");
-		fmt.Scanf("%s", &info.Host)
-		info.Host = strings.TrimSpace(info.Host)
-		if info.Host == "" {
-			info.Host = "localhost"
+		
+		if address == "" {
+			fatal("Please give the address of the local machine")
 		}
 
-		fmt.Printf("Enter port: [4001] ");
-		fmt.Scanf("%d", &info.Port)
-		if info.Port == 0 {
-			info.Port = 4001
+		input := strings.Split(address, ":")
+
+		if len(input) != 2 {
+			fatal("Wrong address %s", address)
+		}
+
+		info.Host = input[0]
+		info.Host = strings.TrimSpace(info.Host)
+		
+		info.Port, err = strconv.Atoi(input[1])
+		
+		if err != nil {
+			fatal("Wrong port %s", address)
 		}
 
 		// Write to file.
@@ -218,6 +223,7 @@ func getInfo(path string) *Info {
 // Send join requests to the leader.
 func Join(s *raft.Server, serverName string) error {
 	var b bytes.Buffer
+	
 	command := &JoinCommand{}
 	command.Name = s.Name()
 

store.go

@@ -3,7 +3,6 @@ package main
 import (
 	"path"
 	"encoding/json"
-	//"fmt"
 	)
 
 // CONSTANTS

trans_handler.go

@@ -64,6 +64,5 @@ func (t transHandler) SendSnapshotRequest(server *raft.Server, peer *raft.Peer,
 			return aersp, nil
 		}
 	}
-	fmt.Println("error send snapshot")
 	return aersp, fmt.Errorf("raftd: Unable to send snapshot: %v", err)
 }

watcher.go

@@ -3,7 +3,6 @@ package main
 import (
 	"path"
 	"strings"
-	"fmt"
 	)
 
 
@@ -30,7 +29,7 @@ func createWatcher() *Watcher {
 func (w *Watcher) add(prefix string, c chan Response) error {
 
 	prefix = "/" + path.Clean(prefix)
-	fmt.Println("Add ", prefix)
+	debug("Add a watche at ", prefix)
 
 	_, ok := w.chanMap[prefix]
 	if !ok {
@@ -40,15 +39,12 @@ func (w *Watcher) add(prefix string, c chan Response) error {
 		w.chanMap[prefix] = append(w.chanMap[prefix], c)
 	}
 
-	fmt.Println(len(w.chanMap[prefix]), "@", prefix)
-
 	return nil
 }
 
 // notify the watcher a action happened
 func (w *Watcher) notify(action int, key string, oldValue string, newValue string, exist bool) error {
 	key = path.Clean(key)
-	fmt.Println("notify")
 	segments := strings.Split(key, "/")
 
 	currPath := "/"
@@ -58,19 +54,18 @@ func (w *Watcher) notify(action int, key string, oldValue string, newValue strin
 
 		currPath := path.Join(currPath, segment)
 
-		fmt.Println(currPath)
-
 		chans, ok := w.chanMap[currPath]
 
 		if ok {
-			fmt.Println("found ", currPath)
+			debug("Notify at ", currPath)
 
 			n := Response {action, key, oldValue, newValue, exist}
+
 			// notify all the watchers
 			for _, c := range chans {
 				c <- n
 			}
-
+			
 			// we have notified all the watchers at this path
 			// delete the map
 			delete(w.chanMap, currPath)