Implement OTLP Exporter to Include Process and Go Metrics

[thinkingabouther]

Currently, when using the OTLP exporter instead of the Prometheus exporter, the system does not emit such metrics as Go metrics and process metrics, which are readily available for Prometheus exporters.

As a consequence, the entire Application section in the suggested Grafana dashboard lacks data.

While I appreciate that it may not be straightforward to incorporate the same set of metrics across different exporters, there are potentially some packages that can provide similar metrics for users only using OTLP exporters:

1. Host instrumentation package for system-related metrics
2. Runtime instrumentation package for certain process-related metrics, including go-routines information.

If the proposed packages align well with your vision for package improvement, I'll be happy to prepare a draft introducing those in krakend-otel

Thank you for your work!

[dhontecillas]

@thinkingabouther I find kind of weird that you use an OTLP Exporter that is not Prometheus, and the only section that has no data is the Application section, mostly because the queries in the Grafana Dashboard are written in the Prometheus query language (so, you should not see any data at all).

So I understand that you might be using some other service to collect metrics (like DataDog, or NewRelic), and you would like to have system metrics reported to those services.

We will take a look at those packages, and I will come back to you with decision about using them.

Thanks for the suggestion, we appreciate it.