refactoring allocate_volume operation

weed-fs/src/pkg/operation/allocate_volume.go

@@ -0,0 +1,33 @@
+package operation
+
+import (
+  "encoding/json"
+  "errors"
+  "net/url"
+  "pkg/storage"
+  "pkg/topology"
+  "pkg/util"
+  "strconv"
+)
+
+type AllocateVolumeResult struct {
+  Error string
+}
+
+func AllocateVolume(dn *topology.DataNode, vid storage.VolumeId, repType storage.ReplicationType) error {
+  values := make(url.Values)
+  values.Add("volume", vid.String())
+  values.Add("replicationType", repType.String())
+  jsonBlob, err := util.Post("http://"+dn.Ip+":"+strconv.Itoa(dn.Port)+"/admin/assign_volume", values)
+  if err != nil {
+    return err
+  }
+  var ret AllocateVolumeResult
+  if err := json.Unmarshal(jsonBlob, &ret); err != nil {
+    return err
+  }
+  if ret.Error != "" {
+    return errors.New(ret.Error)
+  }
+  return nil
+}