Add metric to show participants by origin servername

[NerdyProjects]

Greenlight sets a metadata field called bbb-origin-server-name with the server name of the greenlight instance.

I administrate a BBB server which has two greenlights and a custom application as users. I would like to see an approximate distribution of where clients are coming from.

This adds this metric as bbb_meetings_participant_origin_servername with the servername in the origin field. Meetings with participants without the metadata field set get added to a _no_metadata group:

bbb_meetings_participant_origin_servername{origin="_no_metadata"}

[greenstatic]

This looks interesting. I see that on my BBB server (with Greenlight) I also get the metadata:

<bbb-origin>Greenlight</bbb-origin>

Is this in your case with 2 Greenlight's the same for both?

[greenstatic]

Add to the empty key instead of the magic key _no_metadata:

p_by_m[''] += participants

This way the Prometheus library should generate an empty label, which is more semantically correct than a hardcoded magic string.

[NerdyProjects]

Thanks, I thought about that and decided against; I am happy with you voting for it and changed it accordingly :)

[NerdyProjects]

Is this in your case with 2 Greenlight's the same for both?

https://github.com/bigbluebutton/greenlight/blob/9cb09b49d1a49bcada3b32095ff146593a453b8f/app/controllers/concerns/bbb_server.rb#L71

Yep, only the origin is set. I only went for this metadata key because greenlight is already doing it. I wonder, if this metric is useful for the general public, as I don't know how many people are using a bigbluebutton instance with more than just 1 greenlight... From the semantics at least, origin seems the right name to use to see where a participant is coming from.

[greenstatic]

I just checked another BBB server where we are using the Moodle plugin to integrate BBB into subjects. There are a couple more metdata fields, but the two we're interested in bbb-origin-server-name and bbb-origin are also present.

<bbb-origin>Moodle</bbb-origin>

Let's make this a bit more generic and add the two metadata fields into a single metric.

I propose something like this:

bbb_meetings_participant_origin(server=<bbb-origin-server-name>, name=<bbb-origin>) -

[NerdyProjects]

I went with your proposal, screenshot from prometheus UI after using two greenlights + the custom application (that doesn't set any metadata).

[NerdyProjects]

Should it not be participants in plural?

[greenstatic]

I went with your proposal, screenshot from prometheus UI after using two greenlights + the custom application (that doesn't set any metadata).

Perfect, this is the expected behavior: https://prometheus.io/docs/concepts/data_model/

A label with an empty label value is considered equivalent to a label that does not exist.

---

Should it not be participants in plural?

You are probably right. Let's do the plural version.

[NerdyProjects]

Okay, so be it. Any more wishes? I tested the latest commit as well in my setup, works :-)
(Not having tests feels a bit weird to me, but then it would be a lot of effort to add some...)

[greenstatic]

Looks great, thanks! Creating tests would be great, but the time it would take to mock BBB's API was never justified with my schedule :P

I'll merge this in the v0.6 release branch and also add a couple of panels to the Grafana dashboard. Once it's ready and running a couple of days in my BBB environment I'll make a new release.