General feedback on kestrel connection metrics

[lmolkova]

Is there an existing issue for this?

• I have searched the existing issues

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

Not related to any functional problem.

Describe the solution you'd like

Several kestrel connection metrics could be grouped together to better align with otel recommendations.

See the original discussion in open-telemetry/semantic-conventions#283 (comment)

TL;DR:

kestrel.active_connections, kestrel.queued_connections could be measured with something like kestrel.current.connections or kestrel.connections and additional attribute like kestrel.connection.state = active | queued.

kestrel.upgraded_connections might also be measured with the same counter using an attribute that captures original protocol version (e.g. http.protocol.initial_version).

Additional context

No response

[amcasey]

@JamesNK Please let me know if you're not the right person to look at this.

[JamesNK]

kestrel.active_connections, kestrel.queued_connections could be measured with something like kestrel.current.connections or kestrel.connections and additional attribute like kestrel.connection.state = active | queued.

How would a connection go from queued to active? Would you need to subtract it and then add it again?

e.g.
Connection is queued: kestrel.connections state=queued + 1
Connection is ready: kestrel.connections state=queued - 1 AND kestrel.connections state=active + 1
Connection is finished: kestrel.connections state=active - 1

[lmolkova]

kestrel.active_connections, kestrel.queued_connections could be measured with something like kestrel.current.connections or kestrel.connections and additional attribute like kestrel.connection.state = active | queued.

How would a connection go from queued to active? Would you need to subtract it and then add it again?

e.g. Connection is queued: kestrel.connections state=queued + 1 Connection is ready: kestrel.connections state=queued - 1 AND kestrel.connections state=active + 1 Connection is finished: kestrel.connections state=active - 1

yes, that'd be the way.

Still, the cost (breaking change) may be much higher than the benefit, so I've created this issue only for bookkeeping reasons.