Metric definitions for message/event networking (broker metrics)

[kmcclellan]

I noticed there are semantic definitions for Kafka metrics, many of which could apply to other technologies that send messages/events over a network (AMQP, for example).

It seems valuable to define these metrics in way that is agnostic to technology/protocol, similar to the RPC metrics (in which there exists a similar overlap with HTTP).

[joaopgrassi]

Hi @kmcclellan the messaging working group is tasked to work on "general" messaging metrics as part of the stabilization work. @lmolkova opened a draft PR with some ideas #163. Sorry this slipped and wasn't replied earlier. Let us know if you have other ideas and feel free to leave comments on the PR or join our SIG meetings.

[pyohannes]

For a first stable version of messaging semantic conventions we will focus on client-side instrumentation (producer and consumer) of traces and metrics.

Broker instrumentation is something that will be tackled post-v1.

[kmcclellan]

Makes sense, esp. given not all messaging protocols involve a "broker" role. Generally it might make sense to avoid Kafka-specific language for these semantics. "Publisher" and "subscriber" might serve better to that end (as opposed to "producer"/"consumer"). "Message" probably serves better than "event."

"Client" too may be worthy of avoidance, since pub/sub is quite a different paradigm than client/server (data flows in one direction instead of a bidirectional request/response).

On second thought, I better just take a look at the PR 🤠