stop automatically converting camelCase to snake_case in OpenMetrics exporter

[donbourne]

When naming metrics, I often find need/desire to use camelCase to connect two or more words. It's inconvenient to have the association between those words undone in our OpenMetrics (OM) exporter.

As an example, if I define a metric with name "connectionPool.managedConnections" -- then our current spec dictates that implementations of mpMetrics are expected to change that to snake case.

According to the OM exporter guidelines at
https://prometheus.io/docs/instrumenting/writing_exporters/ :
Prometheus metrics and label names are written in snake_case. Converting camelCase to snake_case is desirable, though doing so automatically doesn’t always produce nice results for things like myTCPExample or isNaN so sometimes it’s best to leave them as-is.

What I'd like to propose is that we leave it up to the developer to decide whether camel case is appropriate, and just stop requiring any automatic conversion to snake case in our spec.

	Metric name in code: 	connectionPool.managedConnections
	Current OM output: 	connection_pool_managed_connections
	Proposed OM output:	connectionPool_managedConnections

WDYT?

@brian-brazil , is it safe for us to stop doing camel case -> snake case autoconversion in metric and label names? will that cause any problems for OM?

[brian-brazil]

That's completely safe, and what I'd recommend these days. I'd not offer an option for this, as metrics having two different names depending on an exposition-level option would be annoying to deal with.

…

On Wed 6 Mar 2019, 12:47 Don Bourne, ***@***.***> wrote: When naming metrics, I often find need/desire to use camelCase to connect two or more words. It's inconvenient to have the association between those words undone in our OpenMetrics (OM) exporter. As an example, if I define a metric with name "connectionPool.managedConnections" -- then our current spec dictates that implementations of mpMetrics are expected to change that to snake case. According to the OM exporter guidelines at https://prometheus.io/docs/instrumenting/writing_exporters/ : *Prometheus metrics and label names are written in snake_case. Converting camelCase to snake_case is desirable, though doing so automatically doesn’t always produce nice results for things like myTCPExample or isNaN so sometimes it’s best to leave them as-is.* What I'd like to propose is that we leave it up to the developer to decide whether camel case is appropriate, and just stop requiring any automatic conversion to snake case in our spec. Metric name in code: connectionPool.managedConnections Current OM output: connection_pool_managed_connections Proposed OM output: connectionPool_managedConnections WDYT? @brian-brazil <https://github.com/brian-brazil> , is it safe for us to stop doing camel case -> snake case autoconversion in metric and label names? will that cause any problems for OM? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#357>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AGyTdrlQSVZmUpoEmtwyAscBF_qy1cPgks5vT7jGgaJpZM4bgzOE> .

[donbourne]

ok, thanks @brian-brazil -- I agree with your point about not having an option for it as that would just make it hard to create dashboards that depend on consistent metric names across servers.