[LightDM] Hard dependency on AccountsService

[Robert Ancell]

On 20 August 2011 02:53, David Edmundson <david at davidedmundson.co.uk> wrote:
> Do you have links to anything explaining about AccountsService?
> Explaining what it is, why it's better than dealing with files directly,
> that sort of thing.
> Dave

I talked to Ray Strode who is one of the main developers of
AccountsService.  Some relevant quotes:
"AcccountsService has always been an ad hoc "serve our needs right
now" type thing.  We don't have much documentation about it."
"Ideally at some point it would become integrated with or superceded
by SSSD at some point in the future." [1]
"It's main purpose at the moment is to serve the needs of GNOME, but
the kind of thing it's doing is general, so it made sense to keep it
on freedesktop so it could get adapted as needed for other desktops if
there is interest."

(I think this is an appropriate position to take given the age of the project)

Unfortunately there isn't much I can point you to.  I'll add a Wiki
page on freedesktop.org that at least provides a basic overview so
there is something to point at.  From my point of view the advantages
are:
- Puts all behaviour in one place - which means less code in lightdm
and less places for bugs
- Caching/storing of information done in one place - currently the
.dmrc may be unreadable by different users, there needs to be a cache,
home directories may not be mounted...
- Consistent API - all user accounts features are accessed using
D-Bus, so don't have to use glib for some features, open files, run
programs for others
- Support for new backends - who knows what sorts of account systems
we will migrate to in the future (e.g. Facebook logins?), a good API
means we don't care
- Able to modify users using the API - it may make sense to add users
from the greeter, so a service like this would make this much easier
- Easier to test - you can make a mock accounts service easier than
faking all the different components of the current system

I think based on this and the feedback received lightdm will
definitely continue to support both legacy and accounts service for
the near future, but I'd like to hope we can move to an API like this
in the future.  So please get this idea on the agendas of the
different desktops :)

Thanks all,
--Robert

[1] https://fedorahosted.org/sssd/