Re: [Duplicity-talk] Recreates and uploads already uploaded volume upon restart?

[edgar . soldin]

On 17.05.2015 17:53, Roman Yepishev wrote:
> Hi,
> 
> With "treats backends as dumb" - do you mean that duplicity does not
> trust backends to actually upload/download/list files when requested?

nope, more that it is a very simple file storage with merely put/get/list/del 
functionality, the most common denominator for fs's if you will. so even if a 
backend supports more refined capabilities, they are not used by duplicity 
right now.
 
> 
> MediaFire upload requires[0] sending file hash along with the payload.
> 
SNIP
> 
> [0]: http://www.mediafire.com/developers/core_api/1.3/upload/#upload_top
> [1]: http://forum.mediafiredev.com/showthread.php?588
> 
> 

ok, sounds properly atomic and looks well defined on a first glance.

taking that into account i'd suggest you to add some way to tell the duplicity 
code that the backend is atomic. maybe just add a class definition to backend.py

class AtomicBackend(Backend):
  """
  signaling that transfers to this backend a truly atomic
  and listings will never include interrupted or partially transferred files
  """

from which you derive your backend and have bin/duplicity check it via

isinstance(object, classinfo)


for the decision to restart from last or last-1, the latter staying the default.

..ede/duply.net