[Buildroot] [PATCH 1/1] Add TCF Agent package

[Norbert Lange]

2017-11-30 22:24 GMT+01:00 Yann E. MORIN <yann.morin.1998 at free.fr>:
> Norbert, Thomas, All,
>
> On 2017-11-30 13:50 +0100, Thomas Petazzoni spake thusly:
>> On Thu, 30 Nov 2017 12:08:17 +0100, Norbert Lange wrote:
>> > -   [ ! -r /etc/default/$DAEMON_NAME ] || . /etc/default/$DAEMON_NAME
>> > This scheme is used to be able to execute that script with 'sh -e'
>> > [ -r /etc/default/$DAEMON_NAME ] && . /etc/default/$DAEMON_NAME would
>> > fail if there is no such file (which is no error)
>> >
>> > Please tell me if I should still use the later line.
>>
>> Interesting reason. Please keep your original proposal then. The
>> ejabberd package is already using this construct. However, all other
>> packages are using the && construct.
>>
>> Unless Yann has a better suggestion for this ?
>
> I think we should write down those rules about startup scripts and their
> configuration files.

Yes, maybe some helper scripts like https://packages.debian.org/sid/lsb-base
would be a good resource for templates and cut down most of the
repetition aswell.
eg.

#!/bin/sh

DAEMON_PATH=/usr/sbin/tcf-agent
DAEMON_NAME=tcf-agent
DAEMON_ARGS="-d -L- -l0"

. /lib/lsb/init-functions

# compute default name for pidfile
DAEMON_USE_PIDFILE=default

# mostly the same for many, if not copy then and adopt
. $DEFAULT_START_STOP

>
> But back on topic for Norbert's use-case. I usually do like he did, but
> I find it hackish nonetheless. I really prefer positive logic anyway,
> like so:
>
>     if [ -r /etc/default/foo.config ]; then
>         . /etc/default/foo.config
>     fi
>
> Yes, that's three lines instead of one, but who cares, really?
>
> However, Norbert's excuse only stands for script that are 'set -e' (i.e.
> they exit as soon as a command exits with a non-zero return code.

There is no excuse (I have no problem using your solution),
but old experiences, preferences and habits like running scripts
with set -e and the "shortcut logic" required - try until one of the
statements is true.
The if will disable exit-on-error, so that's different to both lines.

Btw. I was under the impression that buildroot tries to be as small as possible,
and therefore uses its own init scripts instead the ones from upstream packages.

>
> But this is not the case of the startup script. So if we would really
> want to make it a single line, then positive logic would still to be
> preferred:
>
>     [ -r /etc/default/foo.config ] && . /etc/default/foo.config

Ok.
Norbert
>
> Regards,
> Yann E. MORIN.
>
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