a stable working clustering master node implementation

go/weed/weed_server/raft_server.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"github.com/goraft/raft"
 	"github.com/gorilla/mux"
+	"io/ioutil"
 	"net/http"
 	"net/url"
 	"strings"
@@ -86,6 +87,10 @@ func NewRaftServer(r *mux.Router, version string, peers []string, httpAddr strin
 	return s
 }
 
+func (s *RaftServer) IsLeader() bool {
+	return s.Leader() == s.raftServer.Name()
+}
+
 func (s *RaftServer) Leader() string {
 	l := s.raftServer.Leader()
 
@@ -97,7 +102,7 @@ func (s *RaftServer) Leader() string {
 	return l
 }
 
-func (s *RaftServer) Members() (members []string) {
+func (s *RaftServer) Peers() (members []string) {
 	peers := s.raftServer.Peers()
 
 	for _, p := range peers {
@@ -118,12 +123,13 @@ func (s *RaftServer) Join(peers []string) error {
 	json.NewEncoder(&b).Encode(command)
 
 	for _, m := range peers {
-		glog.V(0).Infoln("Attempting to connect to:", m)
+		target := fmt.Sprintf("http://%s/cluster/join", strings.TrimSpace(m))
+		glog.V(0).Infoln("Attempting to connect to:", target)
 
-		resp, err := http.Post(fmt.Sprintf("http://%s/cluster/join", strings.TrimSpace(m)), "application/json", &b)
-		glog.V(0).Infoln("Post returned: ", err)
+		err := postFollowingOneRedirect(target, "application/json", &b)
 
 		if err != nil {
+			glog.V(0).Infoln("Post returned error: ", err)
 			if _, ok := err.(*url.Error); ok {
 				// If we receive a network error try the next member
 				continue
@@ -132,9 +138,43 @@ func (s *RaftServer) Join(peers []string) error {
 			return err
 		}
 
-		resp.Body.Close()
 		return nil
 	}
 
 	return errors.New("Could not connect to any cluster peers")
 }
+
+// a workaround because http POST following redirection misses request body
+func postFollowingOneRedirect(target string, contentType string, b *bytes.Buffer) error {
+	backupReader := bytes.NewReader(b.Bytes())
+	resp, err := http.Post(target, contentType, b)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	reply, _ := ioutil.ReadAll(resp.Body)
+	statusCode := resp.StatusCode
+
+	if statusCode == http.StatusMovedPermanently {
+		var urlStr string
+		if urlStr = resp.Header.Get("Location"); urlStr == "" {
+			return errors.New(fmt.Sprintf("%d response missing Location header", resp.StatusCode))
+		}
+
+		glog.V(0).Infoln("Post redirected to ", urlStr)
+		resp2, err2 := http.Post(urlStr, contentType, backupReader)
+		if err2 != nil {
+			return err2
+		}
+		defer resp2.Body.Close()
+		reply, _ = ioutil.ReadAll(resp2.Body)
+		statusCode = resp2.StatusCode
+	}
+
+	glog.V(0).Infoln("Post returned status: ", statusCode, string(reply))
+	if statusCode != http.StatusOK {
+		return errors.New(string(reply))
+	}
+
+	return nil
+}

go/weed/weed_server/raft_server_handlers.go

@@ -4,7 +4,9 @@ import (
 	"code.google.com/p/weed-fs/go/glog"
 	"encoding/json"
 	"github.com/goraft/raft"
+	"io/ioutil"
 	"net/http"
+	"strings"
 )
 
 // Handles incoming RAFT joins.
@@ -12,7 +14,9 @@ func (s *RaftServer) joinHandler(w http.ResponseWriter, req *http.Request) {
 	glog.V(0).Infoln("Processing incoming join. Current Leader", s.raftServer.Leader(), "Self", s.raftServer.Name(), "Peers", s.raftServer.Peers())
 	command := &raft.DefaultJoinCommand{}
 
-	if err := json.NewDecoder(req.Body).Decode(&command); err != nil {
+	commandText, _ := ioutil.ReadAll(req.Body)
+	glog.V(0).Info("Command:", string(commandText))
+	if err := json.NewDecoder(strings.NewReader(string(commandText))).Decode(&command); err != nil {
 		glog.V(0).Infoln("Error decoding json message:", err)
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
@@ -37,7 +41,8 @@ func (s *RaftServer) HandleFunc(pattern string, handler func(http.ResponseWriter
 
 func (s *RaftServer) redirectToLeader(w http.ResponseWriter, req *http.Request) {
 	if s.Leader() != "" {
-		glog.V(0).Infoln("Redirecting to", "http://"+s.Leader()+req.URL.Path)
+		//http.StatusMovedPermanently does not cause http POST following redirection
+		glog.V(0).Infoln("Redirecting to", http.StatusMovedPermanently, "http://"+s.Leader()+req.URL.Path)
 		http.Redirect(w, req, "http://"+s.Leader()+req.URL.Path, http.StatusMovedPermanently)
 	} else {
 		glog.V(0).Infoln("Error: Leader Unknown")
@@ -47,7 +52,8 @@ func (s *RaftServer) redirectToLeader(w http.ResponseWriter, req *http.Request)
 
 func (s *RaftServer) statusHandler(w http.ResponseWriter, r *http.Request) {
 	m := make(map[string]interface{})
+	m["IsLeader"] = s.IsLeader()
 	m["Leader"] = s.Leader()
-	m["Members"] = s.Members()
+	m["Peers"] = s.Peers()
 	writeJsonQuiet(w, r, m)
 }