Re: Services and packages in GuixSD

[ludo@gnu.org (Ludovic Courtès)]

Andy Wingo <wingo@igalia.com> skribis:

> On Wed 12 Aug 2015 03:13, 宋文武 <iyzsong@gmail.com> writes:
>
>> Andy Wingo <wingo@igalia.com> writes:
>>
>>> it would be nice if the set of selected packages and services were
>>> grovelled for dbus files.
>>
>> IIUC, the packages in profile need to be known by those services.
>> I think two ways can do this:
>> 1. Build a configuration file for the service with packages listed explicitly.
>> 2. Use a configuration file for the service with respect to profile.
>>
>> Currently, most services go for 1 (eg: dbus, udev). And I don't know a
>> clear way to pass packages field to the monadic service procedure.
>>
>> I did use 2 for slim, by using '/run/current-system/profile/share/xsessions'
>> in its configuration file.
>>
>> How about go with 2 for dbus-service too?
>> By using '/run/current-system/profile/share/dbus-1/system-services' in
>> its configuration file.
>
> Sounds reasonable to me.
>
> This approach introduces a degree of dynamic scoping: the set of
> services that d-bus knows about is dynamically scoped relative to the
> current profile, whatever the current profile is.  So you could do a
> "guix system reconfigure" and then the old d-bus daemon would be able to
> launch new services, without rebooting.  Some people might not like that
> but it sounds fine to me.

Not having to reboot after ‘reconfigure’ is generally desirable, of
course (it just happens to not be fully implemented yet.)  However, the
above means that the reconfigure-but-don’t-switch-until-reboot behavior
would no longer be possible.  So I think we should try to avoid #2 in
most cases.

Ludo’.