[exporter/prometheus] Support Prometheus Created Timestamp feature

[swar8080]

Component(s)

exporter/prometheus

Is your feature request related to a problem? Please describe.

Hello, prometheus has an experimental feature called "Created Timestamp" which solves the problems outlined in this document

Describe the solution you'd like

I think using this involves passing StartTimeUnixNano from the OTEL data model as the Created Timestamp in the prometheus data model. I've got it working locally with just these changes to prometheusexporter/collector.go:

func (c *collector) convertSum(metric pmetric.Metric, resourceAttrs pcommon.Map) (prometheus.Metric, error) {
  ip := metric.Sum().DataPoints().At(0)
  ...
  m, err := prometheus.NewConstMetricWithCreatedTimestamp(desc, metricType, value, ip.StartTimestamp().AsTime(), attributes...)
  ...
}

Describe alternatives you've considered

No response

Additional context

Not sure if the prometheus maintainers think the feature is stable enough to enable by default in the OTEL collector. Or maybe a feature flag makes sense? If not, I can just add this in a fork of the collector for now

cc machine424

[github-actions]

Pinging code owners:

• exporter/prometheus: @Aneurysm9

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[sterziev88]

Hi @swar8080
I saw that you use exporter/prometheus. Could you tell me whether you use OTEL as receiver without prometheus receiver?
Because I want to use that configuration only OTEL receiver and prometheus exporter for metrics but it does not work as I expected. I don't see any metrics in prometheus. I see them in OTEL logs. So I wondered whether you have success with such configuration and maybe can halp me? :)