* Refactoring

* Fix issue that causes a new image store to be created at every start of ucloud-api.
* VM Migration API call now takes hostname instead of host key.
* StorageHandler Classes are introduced. They transparently handles things related to importing of image, make vm out of image, resize vm image, delete vm image etc.
* Loggers added to __init__.py of every ucloud component's subpackage.
* Non-Trivial Timeout Events are no longer logged.
* Fix issue that prevents removal of stopped VMs (i.e VMs that are successfully migrated).
* Improved unit handling added. e.g MB, Mb, mB, mb are all Mega Bytes.
* VM migration is now possible on IPv6 host.
* Destination VM (receiving side of migration of a vm) now correctly expects incoming data on free ephemeral port.
* Traceback is no longer output to screen, instead it goes to log file.
* All sanity checks are put into a single file. These checks are run by ucloud.py before running any of ucloud component.

filescanner/main.py

@@ -6,7 +6,7 @@ import time
 from uuid import uuid4
 
 from etcd3_wrapper import Etcd3Wrapper
-
+from filescanner import logger
 from config import env_vars
 
 
@@ -17,9 +17,10 @@ def getxattr(file, attr):
         value = sp.check_output(['getfattr', file,
                                  '--name', attr,
                                  '--only-values',
-                                 '--absolute-names'])
+                                 '--absolute-names'], stderr=sp.DEVNULL)
         value = value.decode("utf-8")
-    except sp.CalledProcessError:
+    except sp.CalledProcessError as e:
+        logger.exception(e)
         value = None
 
     return value
@@ -63,7 +64,7 @@ try:
     sp.check_output(['which', 'getfattr'])
     sp.check_output(['which', 'setfattr'])
 except Exception as e:
-    print(e)
+    logger.exception(e)
     print('Make sure you have getfattr and setfattr available')
     exit(1)