[Duplicity-talk] DBus API

[Michael Terry]

Hello, maintainers!

Previously on "Issues with writing a duplicity frontend," we were
talking about progress and error feedback.  The ideas of a named pipe
or a duplicity library were discussed.

I counter-propose a DBus API.  DBus is made for exactly this sort of
thing -- interprocess communication -- and has at least the following
advantages:

* It has great language bindings (my frontend is in Vala, but
duplicity is in Python)
* It would be easier for multiple frontend processes to hook into the
same process (a notification applet + main window can both handle the
same duplicity process)
* Has well-defined interactions (e.g. a frontend can ask two things at
the same time asynchronously and get the answers back correctly)
* Is optional (if 'import dbus' doesn't succeed, just don't export a dbus api)
* Can be tacked on today without a codebase rewrite (as a duplicity
library would need)
* It's very easy to debug, program, and document
* I'm offering to help write it

I can spend some time thinking about what the API would look like and
propose something (along with some patches) to the list.  I imagine
that duplicity would claim a dbus name like
'org.nongnu.duplicity.Pid.23438' and start sending signals (maybe
something like "Progress.pulse string:"Backing up XXX..." float:0.34"
for a message and percent-done count).

Would duplicity maintainers accept such a path/patch (module quality,
of course)?

-mt