Emit two spans (server and client)

[dkrizic]

Is your feature request related to a problem? Please describe

This module should emit two spans:

• A server span (the part that receives the external request)
• A client span which is nested in the server span

This is according to the specification of Open Telemetry. I have this scenaria

• Frontend (emits client span)
• Nginx with Otel module as proxy (emits server span, should emit both as described)
• Backend (emits server span)

The problem now is, that components like Tempo Metrics Generator does not connect the Nginx with the actual backend, because it expects a client->server connection.

Describe the solution you'd like

Emit two spans as describe before

Describe alternatives you've considered

No other alternatives.

[p-pautov]

Duplicate of #17. The request makes sense in general, though telemetry processing tools could also handle such situation better...

[dkrizic]

All observability solutions I use have that problem:

• Grafana/Tempo
• Azure Application Insights
• DataDog

Simply because Nginx does not implement the OpenTelemetry spec.