Add metric indicating whether a connection is flow-controlled

[godefroi]

RabbitMQ has the ability to inform administrators when a connection (or channels, or queues) is in "flow control", meaning that the server can't process messages as fast as the connection wants to publish them. This can indicate all kinds of things, things that would be useful to be able to monitor.

It would be great if the exporter made this information available.

[deadtrickster]

Definitely worth having. However, flow is a state of a connection, meaning I should go over all connections and there can be many connections... Also, it doesn't make sense to export all connections probably. Perhaps something like rabbitmq_connections_total{state="ok|blocking|blocked|flow"}.

[godefroi]

Yes, I think that'd be entirely sufficient, without inflating the number of time series.

[deadtrickster]

I added a new metric - rabbitmq_connections_state. New plugin build is attached. Please rename zip to ez! If this works I'll make a new release.

prometheus_rabbitmq_exporter-v3.7.1.1.zip

[godefroi]

I gave this a shot (in RabbitMQ 3.7.2), and when I try to enable the accept plugin, I'm told that it was built with an incompatible erlang. I'm using 19.3, should I be on 20.x instead?

[deadtrickster]

I built in on 20.x, yes. Release versions are built on 19.3. If you can't try on 20.x let me know I'll rebuild on 19.3 and re-upload here

[deadtrickster]

ping

[godefroi]

Sorry, I ended up updating my erlang install and getting distracted with other things. The version you posted seems to work fine, though I do admit I liked the name rabbitmq_connections_total better than rabbitmq_connections_state.

[deadtrickster]

I like connections_total more too, unfortunately it's already assigned to a counter without labels (all existing dashboard will need to get updated + I plan to make this new metric optional). I won't be merging it right now, will try to come up with a better name in next few days. If you have suggestion please share.

[godefroi]

rabbitmq_connections is there, but I don't see a rabbitmq_connections_total. Unless it's not enabled by default?

I would imagine that the new one that breaks out the states would eventually replace rabbitmq_connections, which would become deprecated.

[deadtrickster]

Released with rabbitmq_connections_total. Thanks for the help!