3 files changed, 209 insertions, 0 deletions
diff --git a/weed/wdclient/masterclient.go b/weed/wdclient/masterclient.go
new file mode 100644
index 000000000..347901f1a
--- /dev/null
+++ b/weed/wdclient/masterclient.go
@@ -0,0 +1,95 @@
+package wdclient
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/pb/master_pb"
+	"github.com/chrislusf/seaweedfs/weed/util"
+)
+
+type MasterClient struct {
+	ctx           context.Context
+	name          string
+	currentMaster string
+	masters       []string
+
+	vidMap
+}
+
+func NewMasterClient(ctx context.Context, clientName string, masters []string) *MasterClient {
+	return &MasterClient{
+		ctx:     ctx,
+		name:    clientName,
+		masters: masters,
+		vidMap:  newVidMap(),
+	}
+}
+
+func (mc *MasterClient) GetMaster() string {
+	return mc.currentMaster
+}
+
+func (mc *MasterClient) KeepConnectedToMaster() {
+	glog.V(0).Infof("%s bootstraps with masters %v", mc.name, mc.masters)
+	for {
+		mc.tryAllMasters()
+		time.Sleep(time.Second)
+	}
+}
+
+func (mc *MasterClient) tryAllMasters() {
+	for _, master := range mc.masters {
+		glog.V(0).Infof("Connecting to %v", master)
+		withMasterClient(master, func(client master_pb.SeaweedClient) error {
+			stream, err := client.KeepConnected(context.Background())
+			if err != nil {
+				glog.V(0).Infof("failed to keep connected to %s: %v", master, err)
+				return err
+			}
+
+			glog.V(0).Infof("Connected to %v", master)
+			mc.currentMaster = master
+
+			if err = stream.Send(&master_pb.ClientListenRequest{Name: mc.name}); err != nil {
+				glog.V(0).Infof("failed to send to %s: %v", master, err)
+				return err
+			}
+
+			for {
+				if volumeLocation, err := stream.Recv(); err != nil {
+					glog.V(0).Infof("failed to receive from %s: %v", master, err)
+					return err
+				} else {
+					glog.V(0).Infof("volume location: %+v", volumeLocation)
+					loc := Location{
+						Url:       volumeLocation.Url,
+						PublicUrl: volumeLocation.PublicUrl,
+					}
+					for _, newVid := range volumeLocation.NewVids {
+						mc.addLocation(newVid, loc)
+					}
+					for _, deletedVid := range volumeLocation.DeletedVids {
+						mc.deleteLocation(deletedVid, loc)
+					}
+				}
+			}
+		})
+		mc.currentMaster = ""
+	}
+}
+
+func withMasterClient(master string, fn func(client master_pb.SeaweedClient) error) error {
+
+	grpcConnection, err := util.GrpcDial(master)
+	if err != nil {
+		return fmt.Errorf("fail to dial %s: %v", master, err)
+	}
+	defer grpcConnection.Close()
+
+	client := master_pb.NewSeaweedClient(grpcConnection)
+
+	return fn(client)
+}
diff --git a/weed/wdclient/vid_map.go b/weed/wdclient/vid_map.go
new file mode 100644
index 000000000..2f56b8fce
--- /dev/null
+++ b/weed/wdclient/vid_map.go
@@ -0,0 +1,99 @@
+package wdclient
+
+import (
+	"errors"
+	"fmt"
+	"math/rand"
+	"strconv"
+	"strings"
+	"sync"
+
+	"github.com/chrislusf/seaweedfs/weed/glog"
+)
+
+type Location struct {
+	Url       string `json:"url,omitempty"`
+	PublicUrl string `json:"publicUrl,omitempty"`
+}
+
+type vidMap struct {
+	sync.RWMutex
+	vid2Locations map[uint32][]Location
+}
+
+func newVidMap() vidMap {
+	return vidMap{
+		vid2Locations: make(map[uint32][]Location),
+	}
+}
+
+func (vc *vidMap) LookupVolumeServerUrl(vid string) (serverUrl string, err error) {
+	id, err := strconv.Atoi(vid)
+	if err != nil {
+		glog.V(1).Infof("Unknown volume id %s", vid)
+		return "", err
+	}
+
+	locations := vc.GetLocations(uint32(id))
+	if len(locations) == 0 {
+		return "", fmt.Errorf("volume %d not found", id)
+	}
+
+	return locations[rand.Intn(len(locations))].Url, nil
+}
+
+func (vc *vidMap) LookupFileId(fileId string) (fullUrl string, err error) {
+	parts := strings.Split(fileId, ",")
+	if len(parts) != 2 {
+		return "", errors.New("Invalid fileId " + fileId)
+	}
+	serverUrl, lookupError := vc.LookupVolumeServerUrl(parts[0])
+	if lookupError != nil {
+		return "", lookupError
+	}
+	return "http://" + serverUrl + "/" + fileId, nil
+}
+
+func (vc *vidMap) GetLocations(vid uint32) (locations []Location) {
+	vc.RLock()
+	defer vc.RUnlock()
+
+	return vc.vid2Locations[vid]
+}
+
+func (vc *vidMap) addLocation(vid uint32, location Location) {
+	vc.Lock()
+	defer vc.Unlock()
+
+	locations, found := vc.vid2Locations[vid]
+	if !found {
+		vc.vid2Locations[vid] = []Location{location}
+		return
+	}
+
+	for _, loc := range locations {
+		if loc.Url == location.Url {
+			return
+		}
+	}
+
+	vc.vid2Locations[vid] = append(locations, location)
+
+}
+
+func (vc *vidMap) deleteLocation(vid uint32, location Location) {
+	vc.Lock()
+	defer vc.Unlock()
+
+	locations, found := vc.vid2Locations[vid]
+	if !found {
+		return
+	}
+
+	for i, loc := range locations {
+		if loc.Url == location.Url {
+			vc.vid2Locations[vid] = append(locations[0:i], locations[i+1:]...)
+		}
+	}
+
+}
diff --git a/weed/wdclient/wdclient.go b/weed/wdclient/wdclient.go
new file mode 100644
index 000000000..722f4d061
--- /dev/null
+++ b/weed/wdclient/wdclient.go
@@ -0,0 +1,15 @@
+package wdclient
+
+import (
+	"context"
+)
+
+type SeaweedClient struct {
+	*MasterClient
+}
+
+func NewSeaweedClient(ctx context.Context, clientName string, masters []string) *SeaweedClient {
+	return &SeaweedClient{
+		MasterClient: NewMasterClient(ctx, clientName, masters),
+	}
+}