[NR-120689] disable prometheus normalization feature-gate by default

[sigilioso]

It disables the pkg.translator.prometheus.NormalizeName feature-gate by default.

Background information

The feature gate was enabled by default by reaching the beta state in otelcollector-contrib v0.76.3. When this feature-gate is enabled prometheus metrics names are renamed to match OTEL conventions in the prometheus receiver and we would like to avoid this behavior by default.

Additionally, there is an ongoing discussion to consider providing a configuration option (not a feature-gate) to disable the prometheus normalization: opentelemetry-collector-contrib#21743.

[rogercoll]

Great! Do you know if the idea (in the near future) is to remove this feature gate and be the default behavior?

[sigilioso]

Great! Do you know if the idea (in the near future) is to remove this feature gate and be the default behavior?

The feature-gate is supposed to be eventually removed, therefore the default behavior would be the same as it is at the moment: having the prometheus normalization name enabled. However, since this change is quite disruptive and affects everyone using the prometheus receiver and not using one of the prometheus exporters, including a configuration option to disable prometheus normalization is being considered here.

It seems the feature-gate will be kept for a while, but when it is removed we will need to either rely on this configuration option (if its finally implemented) or take a different approach.

[rogercoll]

Sounds good! Thanks for the explanation and links @sigilioso

[brushknight]

LGTM