FUSE mount: support multiple filers

fix https://github.com/chrislusf/seaweedfs/issues/2015
fix https://github.com/chrislusf/seaweedfs/issues/1531

weed/filesys/wfs.go

@@ -28,8 +28,9 @@ import (
 
 type Option struct {
 	MountDirectory     string
-	FilerAddress       string
-	FilerGrpcAddress   string
+	FilerAddresses     []string
+	filerIndex         int
+	FilerGrpcAddresses []string
 	GrpcDialOption     grpc.DialOption
 	FilerMountRootPath string
 	Collection         string
@@ -95,7 +96,7 @@ func NewSeaweedFileSystem(option *Option) *WFS {
 		},
 		signature: util.RandomInt32(),
 	}
-	cacheUniqueId := util.Md5String([]byte(option.MountDirectory + option.FilerGrpcAddress + option.FilerMountRootPath + util.Version()))[0:8]
+	cacheUniqueId := util.Md5String([]byte(option.MountDirectory + option.FilerGrpcAddresses[0] + option.FilerMountRootPath + util.Version()))[0:8]
 	cacheDir := path.Join(option.CacheDir, cacheUniqueId)
 	if option.CacheSizeMB > 0 {
 		os.MkdirAll(cacheDir, os.FileMode(0777)&^option.Umask)
@@ -259,11 +260,13 @@ func (wfs *WFS) mapPbIdFromLocalToFiler(entry *filer_pb.Entry) {
 func (wfs *WFS) LookupFn() wdclient.LookupFileIdFunctionType {
 	if wfs.option.VolumeServerAccess == "filerProxy" {
 		return func(fileId string) (targetUrls []string, err error) {
-			return []string{"http://" + wfs.option.FilerAddress + "/?proxyChunkId=" + fileId}, nil
+			return []string{"http://" + wfs.getCurrentFiler() + "/?proxyChunkId=" + fileId}, nil
 		}
 	}
 	return filer.LookupFn(wfs)
-
+}
+func (wfs *WFS) getCurrentFiler() string {
+	return wfs.option.FilerAddresses[wfs.option.filerIndex]
 }
 
 type NodeWithId uint64

weed/filesys/wfs_filer_client.go

@@ -1,6 +1,7 @@
 package filesys
 
 import (
+	"github.com/chrislusf/seaweedfs/weed/glog"
 	"github.com/chrislusf/seaweedfs/weed/util"
 	"google.golang.org/grpc"
 
@@ -10,20 +11,36 @@ import (
 
 var _ = filer_pb.FilerClient(&WFS{})
 
-func (wfs *WFS) WithFilerClient(fn func(filer_pb.SeaweedFilerClient) error) error {
+func (wfs *WFS) WithFilerClient(fn func(filer_pb.SeaweedFilerClient) error) (err error) {
 
-	err := util.Retry("filer grpc "+wfs.option.FilerGrpcAddress, func() error {
-		return pb.WithCachedGrpcClient(func(grpcConnection *grpc.ClientConn) error {
-			client := filer_pb.NewSeaweedFilerClient(grpcConnection)
-			return fn(client)
-		}, wfs.option.FilerGrpcAddress, wfs.option.GrpcDialOption)
+	return util.Retry("filer grpc", func() error {
+
+		i := wfs.option.filerIndex
+		n := len(wfs.option.FilerGrpcAddresses)
+		for x := 0; x < n; x++ {
+
+			filerGrpcAddress := wfs.option.FilerGrpcAddresses[i]
+			err = pb.WithCachedGrpcClient(func(grpcConnection *grpc.ClientConn) error {
+				client := filer_pb.NewSeaweedFilerClient(grpcConnection)
+				return fn(client)
+			}, filerGrpcAddress, wfs.option.GrpcDialOption)
+
+			if err != nil {
+				glog.V(0).Infof("WithFilerClient %d %v: %v", x, filerGrpcAddress, err)
+			} else {
+				wfs.option.filerIndex = i
+				return nil
+			}
+
+			i++
+			if i >= n {
+				i = 0
+			}
+
+		}
+		return err
 	})
 
-	if err == nil {
-		return nil
-	}
-	return err
-
 }
 
 func (wfs *WFS) AdjustedUrl(location *filer_pb.Location) string {

weed/filesys/wfs_write.go

@@ -56,7 +56,7 @@ func (wfs *WFS) saveDataAsChunk(fullPath util.FullPath, writeOnly bool) filer.Sa
 
 		fileUrl := fmt.Sprintf("http://%s/%s", host, fileId)
 		if wfs.option.VolumeServerAccess == "filerProxy" {
-			fileUrl = fmt.Sprintf("http://%s/?proxyChunkId=%s", wfs.option.FilerAddress, fileId)
+			fileUrl = fmt.Sprintf("http://%s/?proxyChunkId=%s", wfs.getCurrentFiler(), fileId)
 		}
 		uploadResult, err, data := operation.Upload(fileUrl, filename, wfs.option.Cipher, reader, false, "", nil, auth)
 		if err != nil {