Bug#752075: daemontools-run: Add systemd support

[Gerrit Pape]

Hi, thanks for all the help I already got.

On Mon, Jul 07, 2014 at 04:56:24PM +0200, Michael Biebl wrote:
> Am 07.07.2014 16:36, schrieb Gerrit Pape:
> >> As Ansgar already mentioned, probably the best way to handle that in
> >> Debian is to use the dh-systemd helper.
> >> Unfortuantely the daemontools package doesn't use debhelper, which
> >> complicates that a bit it.
> > 
> > To me, that's not unfortunate. To me, debhelper complicates things.  It
> > can't be that difficult to enable a service, configure it to be enabled
> > by default, and vice-versa.
> 
> The problem here is, that you can't rely on systemd being installed, as
> it is not mandatory. Therefore we re-implemented the relevant bits in
> the init-system-helpers package.
> 
> > To see what snippets debhelper puts into maintainer scripts, can you
> > point me to an example package in Debian that installs simple systemd
> > services, Michael?  I search for files containing systemd in the debian
> > package directory, but with no applicable result.
> 
> There are many packages which use dh-systemd (basically all packages
> depending on init-system-helpers. You can have a look at those.
> 
> Also, Ansgar already more or less answered that question at [1]:
> 
> > As far as I know, this still misses the maintainer script logic that is
> > needed to start the service on installation and stop it again when the
> > package is removed.
> > 
> > There is a debhelper addon to add them, but the daemontools doesn't use
> > debhelper so they have to be added manually. The snippets can be found
> > in autoscripts/* in the init-system-helpers source package (it also
> > needs a runtime dependency on init-system-helpers).
> 
> You can copy the relevant bits to your maintainer scripts, but it has
> the unfortunate effect that updates of dh-systemd will not automatically
> be applied to your package and you'll have to do that manually.

I'm really not keen to add a dependency to daemontools-run, esp. not to
the runit package, just for (un)installing and starting/stopping a
service.

Why isn't it as simple as installing the unit, and then?:

 systemd not installed || start service
 systemd not installed || have service started by default
and
 systemd not installed || stop service
 systemd not installed || have service not started by default

Why do I need a helper for that?

Regards, Gerrit.