add options params for the Assign func

weed/operation/assign_file_id.go

@@ -19,7 +19,13 @@ type AssignResult struct {
 	Error     string `json:"error,omitempty"`
 }
 
-func Assign(server string, count uint64, replication string, collection string, ttl string) (*AssignResult, error) {
+/*
+options params meaning:
+options[0] main data Center
+options[1] main rack
+options[2] main data node
+*/
+func Assign(server string, count uint64, replication string, collection string, ttl string, options ...string) (*AssignResult, error) {
 	values := make(url.Values)
 	values.Add("count", strconv.FormatUint(count, 10))
 	if replication != "" {
@@ -31,6 +37,31 @@ func Assign(server string, count uint64, replication string, collection string,
 	if ttl != "" {
 		values.Add("ttl", ttl)
 	}
+
+	var dataCenter, rack, dataNode string
+	switch len(options) {
+	case 1:
+		dataCenter = options[0]
+	case 2:
+		dataCenter = options[0]
+		rack = options[1]
+	case 3:
+		dataCenter = options[0]
+		rack = options[1]
+		dataNode = options[2]
+	default:
+	}
+
+	if dataCenter != "" {
+		values.Add("dataCenter", dataCenter)
+	}
+	if rack != "" {
+		values.Add("rack", rack)
+	}
+	if dataNode != "" {
+		values.Add("dataNode", dataNode)
+	}
+
 	jsonBlob, err := util.Post("http://"+server+"/dir/assign", values)
 	glog.V(2).Info("assign result :", string(jsonBlob))
 	if err != nil {