randomly pick one replica to write

weed/operation/submit.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"github.com/seaweedfs/seaweedfs/weed/pb"
 	"io"
+	"math/rand"
 	"mime"
 	"net/url"
 	"os"
@@ -179,11 +180,8 @@ func (fi FilePart) Upload(maxMB int, masterFn GetMasterFn, usePublicUrl bool, jw
 					id += "_" + strconv.FormatInt(i, 10)
 				}
 			}
-			fileUrl := "http://" + ret.Url + "/" + id
-			if usePublicUrl {
-				fileUrl = "http://" + ret.PublicUrl + "/" + id
-			}
-			count, e := upload_one_chunk(
+			fileUrl := genFileUrl(ret, id, usePublicUrl)
+			count, e := uploadOneChunk(
 				baseName+"-"+strconv.FormatInt(i+1, 10),
 				io.LimitReader(fi.Reader, chunkSize),
 				masterFn, fileUrl,
@@ -202,7 +200,7 @@ func (fi FilePart) Upload(maxMB int, masterFn GetMasterFn, usePublicUrl bool, jw
 			)
 			retSize += count
 		}
-		err = upload_chunked_file_manifest(fileUrl, &cm, jwt)
+		err = uploadChunkedFileManifest(fileUrl, &cm, jwt)
 		if err != nil {
 			// delete all uploaded chunks
 			cm.DeleteChunks(masterFn, usePublicUrl, grpcDialOption)
@@ -217,7 +215,7 @@ func (fi FilePart) Upload(maxMB int, masterFn GetMasterFn, usePublicUrl bool, jw
 			PairMap:           nil,
 			Jwt:               jwt,
 		}
-		
+
 		uploader, e := NewUploader()
 		if e != nil {
 			return 0, e
@@ -232,7 +230,23 @@ func (fi FilePart) Upload(maxMB int, masterFn GetMasterFn, usePublicUrl bool, jw
 	return
 }
 
-func upload_one_chunk(filename string, reader io.Reader, masterFn GetMasterFn,
+func genFileUrl(ret *AssignResult, id string, usePublicUrl bool) string {
+	fileUrl := "http://" + ret.Url + "/" + id
+	if usePublicUrl {
+		fileUrl = "http://" + ret.PublicUrl + "/" + id
+	}
+	for _, replica := range ret.Replicas {
+		if rand.Intn(len(ret.Replicas)+1) == 0 {
+			fileUrl = "http://" + replica.Url + "/" + id
+			if usePublicUrl {
+				fileUrl = "http://" + replica.PublicUrl + "/" + id
+			}
+		}
+	}
+	return fileUrl
+}
+
+func uploadOneChunk(filename string, reader io.Reader, masterFn GetMasterFn,
 	fileUrl string, jwt security.EncodedJwt,
 ) (size uint32, e error) {
 	glog.V(4).Info("Uploading part ", filename, " to ", fileUrl, "...")
@@ -258,7 +272,7 @@ func upload_one_chunk(filename string, reader io.Reader, masterFn GetMasterFn,
 	return uploadResult.Size, nil
 }
 
-func upload_chunked_file_manifest(fileUrl string, manifest *ChunkManifest, jwt security.EncodedJwt) error {
+func uploadChunkedFileManifest(fileUrl string, manifest *ChunkManifest, jwt security.EncodedJwt) error {
 	buf, e := manifest.Marshal()
 	if e != nil {
 		return e
@@ -277,7 +291,7 @@ func upload_chunked_file_manifest(fileUrl string, manifest *ChunkManifest, jwt s
 		PairMap:           nil,
 		Jwt:               jwt,
 	}
-	
+
 	uploader, e := NewUploader()
 	if e != nil {
 		return e