net/haproxy: Allow exporting prometheus metrics

[onedr0p]

Important notices Before you add a new report, we ask you kindly to acknowledge the following:

[x] I have read the contributing guide lines at https://github.com/opnsense/plugins/blob/master/CONTRIBUTING.md

[x] I have searched the existing issues and I'm convinced that mine is new.

[x] When the request is meant for an existing plugin, I've added its name to the title.

Is your feature request related to a problem? Please describe.

I would like to gather metrics from haproxy with prometheus.

Describe the solution you'd like

Haproxy has native support for a prometheus endpoint, see this blog post for more detail.

It would be cool to have this configurable in the UI.

Describe alternatives you've considered

n/a

Additional context

n/a

[fraenki]

Instead of pointing to a rather lengthy blog post, would you please describe the options you would like to see in OPNsense?

[onedr0p]

Sure, it would be nice to have an option on the haproxy stats menu to turn on the metrics endpoint, which looks like the option would configure this http-request line in the config below.

frontend stats
   bind *:8404
   option http-use-htx
   # This line below turns on prometheus metrics
   http-request use-service prometheus-exporter if { path /metrics }
   stats enable
   stats uri /stats
   stats refresh 10s

[OPNsense-bot]

This issue has been automatically timed-out (after 180 days of inactivity).

For more information about the policies for this repository, please read https://github.com/opnsense/plugins/blob/master/CONTRIBUTING.md for further details.

If someone wants to step up and work on this issue, just let us know, so we can reopen the issue and assign an owner to it.

[fichtner]

@fraenki did you want to take this maybe?

[fraenki]

Maybe. I'll reopen it.

[fraenki]

The next version of the HAProxy plugin will include two ways to enable a Prometheus exporter:

• Settings -> Statistics – a simple one-click option
• Virtual Services -> Public Services – an advanced option (hidden by default) with all frontend customization options