New internal metric added promhttp_metric_handler_errors_total

[dmitryax]

What happened?

promhttp_metric_handler_errors_total metric was added as a result of the migration done #11611.

The metric doesn't seem valuable to be reported for the collector observability. Discussed in https://github.com/open-telemetry/opentelemetry-collector/pull/11611/files#r1953845130. It also doesn't follow the convention we established so far for the internal collector metrics prefixed with otelcol_.

I propose we create a view for dropping it by default.

Collector version

0.119.0

[dmitryax]

it's added by the prometheus server that is started via the SDK. we might be able to drop it via a view

@codeboten the metric cannot be dropped with the views because it's added by the prometheus exporter. It's enabled by passing the registry with promhttp.HandlerOpts in https://github.com/open-telemetry/opentelemetry-go-contrib/blob/4ddf26b05b2ce16c9d91157ffa7151baca36d781/config/v0.3.0/metric.go#L330. In collector, we used to not pass it

opentelemetry-collector/service/telemetry/internal/otelinit/config.go

Line 100 in 2447a81

mux.Handle("/metrics", promhttp.HandlerFor(registry, promhttp.HandlerOpts{}))

.

Not sure what can be done to remove it from prometheus exporter. Can this be exposed as a config option of the go SDK?

[codeboten]

It also doesn't follow the convention we established so far for the internal collector metrics prefixed with otelcol_.

It could be argued that this falls into the category of an instrumentation library metric which doesn't require the prefix (we have the same thing w/ http/grpc instrumentation libraries). I agree that it would be nice to have a way to disable it for end users.

Not sure what can be done to remove it from prometheus exporter. Can this be exposed as a config option of the go SDK?

In the past, options that have been provided via the configuration package have required a spec PR first to ensure the configuration schema doesn't include features that are not spec'd. I could see this falling into the same case as other prometheus exporter options mentioned here: https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/sdk_exporters/prometheus.md#configuration

Do you want to open a PR to the spec to add an option there and we can move forward w/ this?