sysutils/snmp_exporter: clean up Makefile and use prometheus user/group

[fabian.freyer_physik.tu-berlin.de]

Summary

following up on @mat's comments over at D14537, I also updated this port to address the same issues:

• don't run daemons as nobody, but use prometheus user / group
• use DISTVERSION
• correct ordering

[mat]

sysutils/snmp_exporter/files/snmp_exporter.in

43–47

Mmmm, unless the pid file is removed when the daemon is stopped, it may have been created using nobody, and the daemon will not be able to write to it under the prometheus group.

[fabian.freyer_physik.tu-berlin.de]

sysutils/snmp_exporter/files/snmp_exporter.in

43–47

hmm, how should I fix this, add something to pkg-message?

[mat]

sysutils/snmp_exporter/files/snmp_exporter.in

43–47

Why not simply remove the file here before creating it?

[fabian.freyer_physik.tu-berlin.de]

sysutils/snmp_exporter/files/snmp_exporter.in

43–47

As in, just ${RM} -f it, and remove the whole -e check?

[mat]

sysutils/snmp_exporter/files/snmp_exporter.in

43–47

Yes, or you could add a test to check that it has the correct user, and chown or rm it if it has the wrong user. (And make a note to remove this check in like two years when you're sure that it is not needed any more.

[fabian.freyer_physik.tu-berlin.de]

chown pidfile owner

[lwhsu]

I think this is good to go. How do you think, @mat?

[lwhsu]

BTW, @fabian.freyer_physik.tu-berlin.de , how do you think if we move this to net-mgmt to align with prometheus itself and other exporters?

[fabian.freyer_physik.tu-berlin.de]

@lwhsu: sorry for not answering sooner. That sounds like a good idea. What would need to be done to move this?

[lwhsu]

In D14549#328823, @fabian.freyer_physik.tu-berlin.de wrote:

@lwhsu: sorry for not answering sooner. That sounds like a good idea. What would need to be done to move this?

I'll take care of it.