Flow: otelcol.exporter.prometheus component

[rfratto]

Create an OpenTelemetry Collector exporter component called prometheus and expose it as a Flow component called otelcol.exporter.prometheus.

This component would act as a bridge between the otelcol.* component and the prometheus.* components, where it would accept a prometheus.* component receiver to send metrics to. Incoming OpenTelemetry Collector metrics would be converted to Prometheus metrics on the fly before being sent to the configured prometheus.* component receivers.

otelcol.receiver.otlp "default" {
  output {
    metrics = [otelcol.exporter.prometheus.default.input]
  }
}

otelcol.exporter.prometheus "default" {
  send_to = [prometheus.remote_write.default.receiver] 
}

prometheus.remote_write "default" {
  ...
}