otelcol.receiver.otlp should support otelcol.auth.* for http {} block.

[EconomicTouristsArmLate]

Request

Add auth field to otelcol.receiver.otlp config block http (and ideally on grpc too), which accepts handlers from modules like otelcol.auth.bearer and otelcol.auth.basic.

According to docs on eg otelcol.auth.basic, it should be possible to use these auth methods on other otelcol components, which is not the case for otelcol.receiver.otlp.

Use case

I need to expose Alloy publicly to receive OTLP from external sources.
Thus i need to add auth on the receiver.
I do not have access to mTLS based auth, and want to avoid authenticating on my k8s ingress to simplify secrets management.

[ptodev]

Hi, thanks for opening an issue! From what I can tell, it does look like the upstream OTel Collector supports this use case. I agree that we should port it to Alloy.

I am not sure when the Alloy dev team will find time for this though. In the meantime, if anyone would like to submit a PR then I'd be happy to review it.