On Fri, Mar 16, 2012 at 01:07:08PM -0700, Russ Allbery wrote: > This seems like a reasonable idea. Steve, what do you think of having > upstart provide such a shell library? Then init scripts could contain > code along the lines of:
> if [ -r /lib/init/upstart.sh ] ; then > . /lib/init/upstart.sh > ignore_if_upstart > fi > If upstart and systemd can agree on the same invocation semantics for the > shell library, we could even provide a shell library that handled both and > make this more generic. I think this should all go in the lsb-base package (bug #661109). That's already a "standard" shell library for init scripts, which includes lots of functions that aren't part of the LSB standard; I don't see a good reason to contribute to a proliferation of shell libraries here. As for making it generic, while I think there should be a similar function for systemd, there needs to be some way for the init script to indicate which init systems the package actually supports natively; we wouldn't want ignore_if_not_sysvinit() for instance. It also rubs me the wrong way to have the shell library exiting directly from the init script. I'd really prefer an interface such as init_is_upstart() which leaves it open for the init script to handle some of the mentioned corner cases - in particular, allowing for action=stop to DTRT at all points during an upgrade. > > Also, the proposal looks underspecified to me: What happens for other > > actions, like stop/restart/reload/force-reload? > My understanding is that calling those actions directly via the init > script is not necessarily supported and invoke-rc.d should be used > instead. That should probably be spelled out explicitly. Well, in the corner case of a package which calls 'invoke-rc.d restart' in postinst, and upstart is running and we're upgrading to the first version of the package which supports upstart, I see two options: - have the new version of the package call 'invoke-rc.d stop' in the preinst (before the upstart job is unpacked) so that the service is stopped via the init script. - have the new version of the package call '/etc/init.d/$service stop' explicitly in the postinst, since invoke-rc.d will now be looking at the upstart job instead. I prefer the former because it respects policy's existing guidance about not calling init scripts directly, but it also leaves a larger window when the service will be down on upgrade - and the services that have bothered to use 'restart' in the postinst usually do so to prevent exactly this. -- Steve Langasek Give me a lever long enough and a Free OS Debian Developer to set it on, and I can move the world. Ubuntu Developer http://www.debian.org/ slanga...@ubuntu.com vor...@debian.org
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