Expectations for setting service.name in a scraper

[jon-signal]

Hello!

I'm working on a new metrics receiver and am trying to understand the expectations for setting attributes that are required by resource semantic conventions. I'm using https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/receiver/redisreceiver as an example, since the service from which we're trying to extract metrics has a similar "shape:" we can communicate with the service to get a human-readable, plaintext dump of the service's status that we can then parse and publish as metrics. Even if the receiver I'm building doesn't make it into the opentelemetry-collector-contrib repo, using mdatagen and the scaper framework seems to make the job a lot easier.

I notice that the Redis receiver doesn't declare service.name in its metadata and also doesn't seem to set it anywhere in its code. The former doesn't surprise me (since service.name is "defined" elsewhere), but the latter does a little. What's the expectation for setting service.name with the Redis receiver, and for scrapers/receivers in general? I can think of a few scenarios, but none seems quite right.

1. Is the intention that end users will set service.name via environment variables (EDIT: scratch that—I missed that the environment variable approach is for the SDK, not the Collector) or processor? Unless I'm mistaken, this would essentially require one Collector deployment per running service, right?
2. The "Describing Resources through attributes" section of the "Building a receiver" guide gives an example of explicitly assigning conventions.AttributeServiceName via the low-level pcommon.Resource API. I don't see this happening in any contributed receiver, though, and suspect it's something of a model mismatch.
3. …or is this just an oversight in the Redis receiver, and it actually should include service.name somewhere in its metadata/implementation? I don't think this is the case since no other receivers seem to do so, either.

In any case, I can certainly find a way forward, but I am curious about the standard practice is for cases like this. Thanks kindly!