How to get openwebrx stats into collectd

Collectd is a nifty little tool; it collects various bits and pieces of information all around your system in intervals so you can make nice little charts out of it. You can use the openwebrx status interface to get some stats about openwebrx, too, using the curl plugin:

pi@sdr02:~ $ cat /etc/collectd/collectd.conf.d/openwebrx.conf 
LoadPlugin curl

<Plugin curl>
  <Page "openwebrx_stats">
    URL "http://localhost:8073/status"
    <Match>
      Regex "users=([0-9]+)"
      DSType "GaugeAverage"
      type "users"
      Instance "openwebrx_users"
    </Match>
  </Page>
</Plugin>