Silent crash when not using --debug with prometheus exporter

[spanthetree]

Hi, having a similar issue to #65 where vaping will immediately crash when the output is set to prometheus (using vaping-exporter).

OS: Ubuntu 18.04
Py: 3.6.2

This problem does NOT occur when using vodka for example as the output, instead of prometheus.

[grizz]

Interesting, hadn't seen that before. We'll try to reproduce.

[mattlan]

I'm also having this issue (vaping 1.4.2) with the prometheus exporter, is reproducible 100% of the time. Run without --debug and it will die within a few minutes, with --debug and it works as expected.

[grizz]

I've just recently set up vaping for prometheus and can reproduce it, I'm just struggling to find time for a fix as it looks like it's in prometheus_client, will try to prioritize it.

@mattlan How are you deploying it?

[mattlan]

I am currently using vaping with pypy, because I needed something that was easy to distribute and that also works on ancient EL6 hosts without modern python. So basically a tgz I threw together myself with pypy and vaping/etc already included. Then I am running it like this nohup /srv/vaping/bin/vaping start --home /srv/vaping/config --debug </dev/null >/dev/null 2>&1 &.