On Thu, Jan 21, 2016 at 06:52:07PM -0500, Steve Litt wrote:

[cut]

>
> Here's pseudocode for the typical Runit run script that runs as root,
> doesn't need GUI capabilities, and needs no environment variables:
>
> =================================================
> #!/bin/sh
> exec 2>&1
> exec /path/to/daemon --run_in_forground other_arguments
> =================================================
>

Steve, I don't know anything of runit, but you would agree anyway that
your pseudocode would be enough also for a sysvinit script of a daemon
that runs as root, does not need GUI capabilities, and needs no
external configuraion or environment variables.

But this is not the typical use case. Usually a typical service does
need external configuration, should be responsive to what happens
around them also *after* they are started, and has all sorts of
peculiarities and special cases. Not to forget the fact that you might
want it to collaborate with other parts of your system, e.g. PAM, just
to mention one of the usual suspects.

I agree that what we have today as sysvinit scripts is mostly the
result of unnecessary complications accumulated throughout the last 20
years, but unfortunately sometimes "complications" is the name of
those necessary things which allow more complex things to work
together in a meaningful way.

TAoUP [1] has an entire chapter dedicated to complexity, and Eric
S. Raymond explains very well (despite I don't like him) that
sometimes complexity is just unavoidable, because the cost of avoiding
it is not having something that is deemed necessary.

My2Cents

KatolaZ

[1] http://catb.org/esr/writings/taoup/

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[ Enzo Nicosia aka KatolaZ --- GLUG Catania -- Freaknet Medialab ]
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