Refactor _start_transfer

Currently we create an instance of FixedIntervalLoopingCall (to
update lease progress)  even if the write handle is not of type
VmdkWriteHandle. Also, we do not create any progress updater for
VmdkReadHandle. Refactoring _start_transfer to create updater
only if the handle is of type VmdkHandle.

Change-Id: I6e306a5ff453f16e9bdfbd97996206db7db8447e

1 files changed, 16 insertions, 6 deletions

diff --git a/oslo_vmware/image_transfer.py b/oslo_vmware/image_transfer.py
index eb6d6c5..fa29385 100644
--- a/oslo_vmware/image_transfer.py
+++ b/oslo_vmware/image_transfer.py
@@ -40,14 +40,21 @@ NFC_LEASE_UPDATE_PERIOD = 60  # update NFC lease every 60sec.
 CHUNK_SIZE = 64 * units.Ki  # default chunk size for image transfer
 
 
+def _create_progress_updater(handle):
+    if isinstance(handle, rw_handles.VmdkHandle):
+        updater = loopingcall.FixedIntervalLoopingCall(handle.update_progress)
+        updater.start(interval=NFC_LEASE_UPDATE_PERIOD)
+        return updater
+
+
 def _start_transfer(read_handle, write_handle, timeout_secs):
-    # write_handle could be an NFC lease, so we need to periodically
-    # update its progress
-    update_cb = getattr(write_handle, 'update_progress', lambda: None)
-    updater = loopingcall.FixedIntervalLoopingCall(update_cb)
+    # read_handle/write_handle could be an NFC lease, so we need to
+    # periodically update its progress
+    read_updater = _create_progress_updater(read_handle)
+    write_updater = _create_progress_updater(write_handle)
+
     timer = timeout.Timeout(timeout_secs)
     try:
-        updater.start(interval=NFC_LEASE_UPDATE_PERIOD)
         while True:
             data = read_handle.read(CHUNK_SIZE)
             if not data:
@@ -67,7 +74,10 @@ def _start_transfer(read_handle, write_handle, timeout_secs):
         raise exceptions.ImageTransferException(msg, excep)
     finally:
         timer.cancel()
-        updater.stop()
+        if read_updater:
+            read_updater.stop()
+        if write_updater:
+            write_updater.stop()
         read_handle.close()
         write_handle.close()