[Buildroot] [PATCH] package/quagga: Add systemd.service file

[Nathaniel Roach <nroach44@gmail.com>]

On 29/06/16 17:53, Arnout Vandecappelle wrote:
> (Mainly improving my systemd knowledge here :-)
>
> On 29-06-16 09:06, Nathaniel Roach wrote:
>> On 27/06/16 05:09, Arnout Vandecappelle wrote:
>>> On 25-06-16 19:02, Nathaniel Roach wrote:
> [snip]
>>>    However, since the Wants= is added for zebra, it would make sense to create the
>>> zebra symlink, no?
>> No, systemd will automatically start zebra when it's needed. It's not needed
>> until one of the other daemons start (which systemd will start zebra beforehand
>> if the daemon is local). If they are remote, the user can enable zebra themselves.
>   So, if there is a Wants=quagga at zebra.service line, then systemd will look for
> quagga at zebra.service in /usr/lib/systemd/services, and failing that it will
> automatically try quagga at .service? Nice!
Pretty much! 
/etc/systemd/system/multi-user.target.wants/quagga at zebra.service is 
installed on systemctl enable [...] and it's just a symlink to
quagga at .service
> [snip]
>>>> +Wants=quagga at zebra.service
>>>    I just realize now: this line should probably be removed when
>>> BR2_PACKAGE_QUAGGA_ZEBRA is not set.
>> Also true, however that's why I said Wants= and not Requires= so systemd handles
>> the lack of zebra fine.
>   So in case zebra doesn't exist, systemd will still try to execute the service
> file, but the ExecStart command will fail because /usr/sbin/zebra doesn't exist,
> right? But in that case, won't it retry every second (Restart=on-failure) and
> spam the journal horribly?
>
>   Maybe there should be a ConditionFileIsExecutable in the [Unit] section?
That was a good condition that I didn't think of. In that case the unit 
will fail and restart until it hits the start limit. I've since added in 
the Condition stanza and everything works as intended.
>
>
>   Regards,
>   Arnout
>
>