Add span IDs

[goodspark]

Motivation

I think this will address #1481

Having a general way to add span ID information to events being output as logs will enable trace-to-log linking in various tracing services.

[davidbarsky]

I'm sorry, we're not going to accept this PR. tracing's span IDs are generally meant to be opaque identifiers that are unique within a process for currently open spans. They are not meant to be globally unique identifiers like UUIDs or an OpenTelemetry span ID. If you'd like to read more, take a look at this documentation.

While I think we should make it easier to integrate different layers, I think whatever approach is done approach requires care. tracing needs to be generic over different external integrations and that's pretty hard. I think it's fair to say that we don't have the time to design such an approach and recording a given distributed tracing ID field as an field in a span is a good enough approach for now.

[hawkw]

Hmm, I think it would be fine to have the option to include tracing span IDs in the JSON format --- although they are not globally unique, they can be used to e.g. visually distinguish two distinct spans with the same name and fields. I think it would be okay to have a formatter configuration to include them, as long as the constraints of tracing's IDs are clearly documented in the API for enabling that configuration...

[goodspark]

Does this mean #1481 should be closed as a wont-do?

[davidbarsky]

Does this mean #1481 should be closed as a wont-do?

No. We should probably keep it open and document the workaround.

[goodspark]

What's the workaround? It wasn't clear to me. Unless you mean manually adding it to every place we emit an event. Bc that seems too painful a user experience. If this were behind config options with caveat docs as hawkw said, would it be acceptable?

[davidbarsky]

Sorry, it's:

I think it's fair to say that we don't have the time to design such an approach and recording a given distributed tracing ID field as an field in a span is a good enough approach for now.

Most layers/formatters will include information from spans when printing events.