To bring it back to the package at hand, because talking about abstractions isn't helpful here IMHO: On 06/21/2016 02:39 PM, Simon McVittie wrote: > On Tue, 21 Jun 2016 at 13:49:27 +0200, Ansgar Burchardt wrote: >> It should be fine to only provide a unit for "systemd --user" >> and people who don't use systemd or libpam-systemd then have to >> configure the service start and stop themselves. > > Yes up to a point, but not if the "systemd --user" integration is > considered to be critical to the specific binary package with the > dependency. Well, in this case it's rather simple, the units of the software in question have the following effect [*]: - at login a certain command is executed (profile-sync-daemon resync) - from then on the same command is executed every hour - at logout a different command is executed (profile-sync-daemon unsync) Plus the dependencies of the user units are done in such a way that only ever one of these commands is executed at the same time. So what happens here is that profile-sync-daemon is not actually a daemon, but rather a command that is executed periodically to perform a specific action. Off the top of my head, especially considering the guarantee of only ever executing one of these commands at a time, I don't know of anything out of the box that could do that on non-systemd systems. That said, it should really not be difficult to write some simple program that runs in the background, properly handles X11 session termination (i.e. recognizes it and performs actions), and then executes the commands in the same fashion. (And hook that up via /etc/X11/Xsession.d, with a check to disable it if systemd is running, because there you wouldn't need it.) So I think the systemd dependency here is just because the author of the upstream software didn't actually want to write a long running program, and used systemd's features to have an action take place repeatedly. So I see three options for the packager of this software: a) Declare a systemd-sysv + libpam-systemd dependency for now. b) Don't explicitly declare the systemd-sysv dependency (but do depend on libpam-systemd, so that user sessions are enabled on systemd systems), and mention in either README.Debian or so that people will have to figure out on their own how to start it if they don't run systemd. (I would suspect that the program itself doesn't really require systemd, just from looking at my analysis of the units.) c) Create the solution for running this on non-systemd systems yourself. (This would be more work though.) In my personal opinion, b) and c) seem more reasonable to me than a), because while b) doesn't offer Debian's "runs out of the box" experience on non-systemd systems, it at least allows people to install the software and figure it out for themselves. Regards, Christian [*] Technically, since systemd user instances aren't directly tied to sessions, the semantics are actually slightly different, in that login only means the first login, i.e. separate parallel logins e.g. via SSH (while the initial session is still active) don't have any effect, but the "logout" action will only be taken once there are no more sessions of a given user at a given time. (Even if the remaining session wasn't graphical.) Also, if the user enables logind's lingering, this will change semantics again. But on a typical desktop system (for which this is intended), where one logs in graphically and only once, the login/logout semantics I mentioned do apply.
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