Dash in controller name cause metrics to be dropped

[JRBANCEL]

In what area(s)?

/area monitoring
/area networking
/kind bug

What version of Knative?

HEAD

Expected Behavior

Controller metrics are emitted.

Actual Behavior

Failed to export to Prometheus: cannot register the collector: descriptor Desc{fqName: "controller-ingress-istio_work_queue_depth", help: "Depth of the work queue", constLabels: {}, variableLabels: [reconciler]} is invalid: "controller-ingress-istio_work_queue_depth" is not a valid metric name

Metrics names are generated by concatenating the component name and the metric name.
In this case:

sharedmain.Main("controller-ingress-istio", clusteringress.NewController)

the prefix contains a -, which is not allowed in a metric name: see validation.

Solution

Rename the component to not contain a -.
Also applies to controller-certificate-cert-manager.

[JRBANCEL]

/assign

[JRBANCEL]

According to Prometheus, the namespace must be a single word: https://prometheus.io/docs/practices/naming/#metric-names

...should have a (single-word) application prefix relevant to the domain the metric belongs to. The prefix is sometimes referred to as namespace by client libraries. For metrics specific to an application, the prefix is usually the application name itself.

[vagababov]

Should vs Must :-) but sure.