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Συντάκτης: Steve Litt
Ημερομηνία:  
Προς: dng
Αντικείμενο: Re: [DNG] Runit service depend another script not daemon
On Fri, 5 Jul 2019 20:35:45 +0200
viverna <viverna@???> wrote:

> il devuanizzato Steve Litt <slitt@???> il 04-07-19
> 22:23:51 ha scritto:
> >Hi viverna,
> >
> >I have a very different viewpoint than most people, so the following
> >is *my opinion* and is not in the mainstream.
> >
> >I think that, for both s6 and runit, run scripts (and any finish
> >scripts or environment files) should come from a small committee of
> >runit/s6 experts, NOT from the overworked "upstreams" who created the
> >software, nor the overworked distro-based maintainers who adapt the
> >software to the distro. During the Debian-User systemd war, one of
> >the greatest sources of resistance to multi-initism was "upstreams"
> >and maintainers who bitched about now having to take care of an
> >extra set of init scripts.
> >
> >If each "upstream" simply documents:
> >
> >1) How to run the software, in the foreground, without excessive
> > logging.
> >2) The preferred user and group to run the software.
> >3) What daemons should already be running before the software.
> >4) Any special state circumstances necessary to start the software.
> >For
> > instance:
> > * Network up
> > * Such and such file with so and so permissions
> > * Etc.
> >5) Any cleanup that must be done after the software finishes or
> >crashes. 6) Any environment vars the software is responsive to.
> >7) The software's response to any signals.
> >8) Any special logging the software does all by itself.
> >9) Does it require a "twin" daemon, like smbd and nmbd, and if so,
> > which should start first?
> >
> >Possessing the preceding info, it's easy to make an s6 or runit run
> >script, finish script, and if necessary environment file. In most
> >cases only the first 4 are really necessary. If an "upstream"
> >refuses to answer the questions, the info can probably be gleaned
> >from the software's systemd unit file.
> >
> >This list of questions could be sent to each "upstream", and the
> >answers will almost 1 for 1 correspond to the run script.
> >
> >The runit package could install tree /etc/runit/scriptdirs and the
> >directory /etc/sv, and a daemon's (call it mydaemon) install could
> >include something like the following:
> >
> >if -d /etc/runit/scriptdirs; then
> > ln -s /etc/runit/scriptdirs/mydaemon /etc/sv/mydaemon
> >fi
> >
> >Uninstalling the mydaemon package would remove
> >symlink /etc/sv/mydaemon.
> >
> >My method runs counter to the way it's always been done, and I always
> >get a lot of pushback when suggesting it, but my way would probably
> >limit resistance from "upstreams" and maintainers, and would not
> >require those people to become runit and/or s6 experts. Meanwhile, it
> >would be trivial for a couple runit and s6 experts to write the
> >actual startup files, based on the "upstream"s answer to a few simple
> >questions.
> >
> >SteveT
> >
> >Steve Litt
> >July 2019 featured book: Troubleshooting Techniques
> >     of the Successful Technologist
> >http://www.troubleshooters.com/techniques
> >_______________________________________________
> >Dng mailing list
> >Dng@???
> >https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng  
> Sounds like a good solution to me, however the main problem remains;
> all packaged daemon must implement (at install phase) the simple
> script you specified above.
> How to do? Devuan, if I'm not wrong, get packages from Debian for all 
> packages with no systemd hard dependency.
> Devuan is a great distro and has excellent developers but limited 
> manpower.


I see what you mean.

> I think that fork all daemon is not praticable.


Now I see what you're saying. You're probably right.

> Instead it's possible
> inject in all daemon's install a piece of posix shell?
> Workaround script on event "DPkg::Post-Invoke" as I said in the
> previous email?


You know much more than I do about packaging. Given something like
event "DPkg::Post-Invoke", all it would need to do is call a
shellscript, with the argument of the daemon name, and the shellscript
could make the necessary symlinks or whatever. All the heavy lifting
would still be done in the runit-runscripts package.

> Else is better another strategy?


Maybe just put *all* the daemons in /etc/sv, whether those daemons are
installed or not. A diagnostic shellscript could pre-test something
in /etc/sv to see if everything needed is installed.

> These are questions that I ask myself but it's important for the
> future of Devuan and init systems diversity.
> The choice of Debian is to follow freedesktop "fancy" guy.


A lot of distros have followed that shiny object.

> It is not
> difficult to think of the day when Debian will remove completely
> sysvinit script in all packages.


Pre-Cisely!

SteveT

Steve Litt 
July 2019 featured book: Troubleshooting Techniques
     of the Successful Technologist
http://www.troubleshooters.com/techniques