[systemd-devel] start service only on specific exit status of some prog

[Barry Scott]

On Wednesday 24 August 2011 17:25:40 Marius Tolzmann wrote:
> On 24.08.2011 16:01, Lennart Poettering wrote:
> > On Tue, 02.08.11 17:06, Marius Tolzmann (tolzmann at molgen.mpg.de) wrote:
> >>
> >> is there a way to execute a program and take its exit status to
> >> evaluate the condition? like ConditionExec or whatever.
> >>
> >> is this already possible without getting a "failed" service?
> >
> > Hmm, so I think we should make sure that systemd unit files don't become
> > a programming language. i.e. there needs to be a limit on what we want
> > to allow to be expressed in unit files. I am tempted to say that checks
> > like this are probably beyond that limit, and fall into the domain where
> > shell scripts should be used. I.e. write a tiny shell script that is
> > executed in ExecStartPre invokes your tool, checks the return code and
> > then fails if needed.
> 
> Hi... thanks for the reply..
> 
> i really don't want to implement complex checks within unit files.. but 
> currently systemd lacks a clean possibility to implement complex checks 
> outside of unit files.
> 

snip...

Why not have the complex logic run before the system reboots and
chaneg the systemd dependancies? For example in our application
a TV card is optional. We could check at run time during boot,
but it seemed cleaner to us to change the dependancies.

Barry