Allow multiple metrics exporter (Prometheus, OpenTelemetry)

[thepabloaguilar]

Allow multiple metrics exporter (Prometheus, OpenTelemetry)

[markphelps]

Oh nice! Should be a pretty small lift then to get support for the OTLP exporter then. I can create a PR for this tonight!

Thanks for the reminder @GeorgeMac

[markphelps]

Great idea @thepabloaguilar !!

[markphelps]

One thing to note is that we arent currently using the OTEL prometheus exporter, we are using the prometheus lib itself to capture metrics and 'export' them using the promhttp lib mounted at /metrics

I think in order to cleanly accomplish the goal of this issue, we would need to change out the metrics collection APIs to use the OTEL lib instead of the prometheus lib itself, something like they do here in the prometheus OTEL exporter example:

https://github.com/open-telemetry/opentelemetry-go/blob/b34cfc47c4e0240b728f28e62f829dc25408746b/example/prometheus/main.go#L30-L55

[GeorgeMac]

One thing to note is that we arent currently using the OTEL prometheus exporter, we are using the prometheus lib itself to capture metrics and 'export' them using the promhttp lib mounted at /metrics

I think in order to cleanly accomplish the goal of this issue, we would need to change out the metrics collection APIs to use the OTEL lib instead of the prometheus lib itself, something like they do here in the prometheus OTEL exporter example:

https://github.com/open-telemetry/opentelemetry-go/blob/b34cfc47c4e0240b728f28e62f829dc25408746b/example/prometheus/main.go#L30-L55

We moved to the otel metrics API and prom provider for it a while back now. This is the thing than broke every week because the API was unstable for so long. But it’s all good now, we’re good to go with other otel provider impls for metrics.

flipt/internal/metrics/metrics.go

Line 23 in 2490bb5

otel.SetMeterProvider(provider)