master can redirect GET/DELETE/POST requests to volume servers. So

clients does not always need to remember the volume server locations.
This is good for low~medium sized web site traffic.

weed-fs/src/cmd/weed/master.go

@@ -54,7 +54,7 @@ func dirLookupHandler(w http.ResponseWriter, r *http.Request) {
 		machines := topo.Lookup(volumeId)
 		if machines != nil {
 			ret := []map[string]string{}
-			for _, dn := range *machines {
+			for _, dn := range machines {
 				ret = append(ret, map[string]string{"url": dn.Url(), "publicUrl": dn.PublicUrl})
 			}
 			writeJson(w, r, map[string]interface{}{"locations": ret})
@@ -178,6 +178,22 @@ func volumeStatusHandler(w http.ResponseWriter, r *http.Request) {
 	writeJson(w, r, m)
 }
 
+func redirectHandler(w http.ResponseWriter, r *http.Request) {
+	vid, _, _ := parseURLPath(r.URL.Path)
+	volumeId, err := storage.NewVolumeId(vid)
+	if err != nil {
+		debug("parsing error:", err, r.URL.Path)
+		return
+	}
+	machines := topo.Lookup(volumeId)
+	if machines != nil && len(machines) > 0 {
+		http.Redirect(w, r, "http://"+machines[0].PublicUrl+r.URL.Path, http.StatusMovedPermanently)
+	} else {
+		w.WriteHeader(http.StatusNotFound)
+		writeJson(w, r, map[string]string{"error": "volume id " + volumeId.String() + " not found. "})
+	}
+}
+
 func runMaster(cmd *Command, args []string) bool {
 	if *mMaxCpu < 1 {
 		*mMaxCpu = runtime.NumCPU()
@@ -192,6 +208,7 @@ func runMaster(cmd *Command, args []string) bool {
 	http.HandleFunc("/dir/status", dirStatusHandler)
 	http.HandleFunc("/vol/grow", volumeGrowHandler)
 	http.HandleFunc("/vol/status", volumeStatusHandler)
+	http.HandleFunc("/", redirectHandler)
 
 	topo.StartRefreshWritableVolumes(*garbageThreshold)
 

weed-fs/src/pkg/topology/topology.go

@@ -57,7 +57,7 @@ func (t *Topology) loadConfiguration(configurationFile string) error {
 	return e
 }
 
-func (t *Topology) Lookup(vid storage.VolumeId) *[]*DataNode {
+func (t *Topology) Lookup(vid storage.VolumeId) []*DataNode {
 	for _, vl := range t.replicaType2VolumeLayout {
 		if vl != nil {
 			if list := vl.Lookup(vid); list != nil {

weed-fs/src/pkg/topology/volume_layout.go

@@ -42,8 +42,8 @@ func (vl *VolumeLayout) isWritable(v *storage.VolumeInfo) bool{
     return uint64(v.Size) < vl.volumeSizeLimit && v.Version == storage.CurrentVersion
 }
 
-func (vl *VolumeLayout) Lookup(vid storage.VolumeId) *[]*DataNode {
-	return &vl.vid2location[vid].list
+func (vl *VolumeLayout) Lookup(vid storage.VolumeId) []*DataNode {
+	return vl.vid2location[vid].list
 }
 
 func (vl *VolumeLayout) PickForWrite(count int) (*storage.VolumeId, int, *VolumeLocationList, error) {