Add retrying logic to wait for other peers during cluster bootstrapping.

go/topology/topology.go

@@ -52,21 +52,26 @@ func NewTopology(id string, confFile string, seq sequence.Sequencer, volumeSizeL
 }
 
 func (t *Topology) IsLeader() bool {
-	return t.RaftServer == nil || t.Leader() == t.RaftServer.Name()
+	if leader, e := t.Leader(); e == nil {
+		return leader == t.RaftServer.Name()
+	}
+	return false
 }
 
-func (t *Topology) Leader() string {
+func (t *Topology) Leader() (string, error) {
 	l := ""
 	if t.RaftServer != nil {
 		l = t.RaftServer.Leader()
+	} else {
+		return "", errors.New("Raft Server not ready yet!")
 	}
 
 	if l == "" {
 		// We are a single node cluster, we are the leader
-		return t.RaftServer.Name()
+		return t.RaftServer.Name(), errors.New("Raft Server not initialized!")
 	}
 
-	return l
+	return l, nil
 }
 
 func (t *Topology) loadConfiguration(configurationFile string) error {

go/weed/weed_server/master_server.go

@@ -77,12 +77,16 @@ func NewMasterServer(r *mux.Router, port int, metaFolder string,
 func (ms *MasterServer) SetRaftServer(raftServer *RaftServer) {
 	ms.Topo.RaftServer = raftServer.raftServer
 	ms.Topo.RaftServer.AddEventListener(raft.LeaderChangeEventType, func(e raft.Event) {
-		glog.V(0).Infoln("[", ms.Topo.RaftServer.Name(), "]", ms.Topo.RaftServer.Leader(), "becomes leader.")
+		if ms.Topo.RaftServer.Leader() != "" {
+			glog.V(0).Infoln("[", ms.Topo.RaftServer.Name(), "]", ms.Topo.RaftServer.Leader(), "becomes leader.")
+		}
 	})
 	if ms.Topo.IsLeader() {
 		glog.V(0).Infoln("[", ms.Topo.RaftServer.Name(), "]", "I am the leader!")
 	} else {
-		glog.V(0).Infoln("[", ms.Topo.RaftServer.Name(), "]", ms.Topo.RaftServer.Leader(), "is the leader.")
+		if ms.Topo.RaftServer.Leader() != "" {
+			glog.V(0).Infoln("[", ms.Topo.RaftServer.Name(), "]", ms.Topo.RaftServer.Leader(), "is the leader.")
+		}
 	}
 }
 

go/weed/weed_server/raft_server.go

@@ -10,6 +10,7 @@ import (
 	"github.com/goraft/raft"
 	"github.com/gorilla/mux"
 	"io/ioutil"
+	"math/rand"
 	"net/http"
 	"net/url"
 	"strings"
@@ -59,13 +60,28 @@ func NewRaftServer(r *mux.Router, peers []string, httpAddr string, dataDir strin
 
 	// Join to leader if specified.
 	if len(s.peers) > 0 {
-		glog.V(0).Infoln("Joining cluster:", strings.Join(s.peers, ","))
-
 		if !s.raftServer.IsLogEmpty() {
-			glog.V(0).Infoln("Cannot join with an existing log")
+			glog.V(0).Infoln("Starting cluster with existing logs.")
 		} else {
-			if err := s.Join(s.peers); err != nil {
-				return nil
+			glog.V(0).Infoln("Joining cluster:", strings.Join(s.peers, ","))
+			time.Sleep(time.Duration(rand.Intn(1000)) * time.Millisecond)
+			firstJoinError := s.Join(s.peers)
+			if firstJoinError != nil {
+				glog.V(0).Infoln("No existing server found. Starting as leader in the new cluster.")
+				_, err := s.raftServer.Do(&raft.DefaultJoinCommand{
+					Name:             s.raftServer.Name(),
+					ConnectionString: "http://" + s.httpAddr,
+				})
+				if err != nil {
+					glog.V(0).Infoln(err)
+					return nil
+				}
+			}
+			var err error
+			for err != nil {
+				glog.V(0).Infoln("waiting for peers on", strings.Join(s.peers, ","), "...")
+				time.Sleep(time.Duration(1000+rand.Intn(2000)) * time.Millisecond)
+				err = s.Join(s.peers)
 			}
 			glog.V(0).Infoln("Joined cluster")
 		}

go/weed/weed_server/raft_server_handlers.go

@@ -40,10 +40,10 @@ func (s *RaftServer) HandleFunc(pattern string, handler func(http.ResponseWriter
 }
 
 func (s *RaftServer) redirectToLeader(w http.ResponseWriter, req *http.Request) {
-	if s.topo.Leader() != "" {
+	if leader, e := s.topo.Leader(); e == nil {
 		//http.StatusMovedPermanently does not cause http POST following redirection
-		glog.V(0).Infoln("Redirecting to", http.StatusMovedPermanently, "http://"+s.topo.Leader()+req.URL.Path)
-		http.Redirect(w, req, "http://"+s.topo.Leader()+req.URL.Path, http.StatusMovedPermanently)
+		glog.V(0).Infoln("Redirecting to", http.StatusMovedPermanently, "http://"+leader+req.URL.Path)
+		http.Redirect(w, req, "http://"+leader+req.URL.Path, http.StatusMovedPermanently)
 	} else {
 		glog.V(0).Infoln("Error: Leader Unknown")
 		http.Error(w, "Leader unknown", http.StatusInternalServerError)
@@ -53,7 +53,11 @@ 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.topo.IsLeader()
-	m["Leader"] = s.topo.Leader()
+	if leader, e := s.topo.Leader(); e == nil {
+		m["Leader"] = leader
+	} else {
+		m["Leader"] = ""
+	}
 	m["Peers"] = s.Peers()
 	writeJsonQuiet(w, r, m)
 }