Add system specific conventions for OpenAI

[drewby]

Fixes #1370

Changes

Adds system specific attributes for OpenAI.

• gen_ai.openai.request.seed
• gen_ai.openai.request.response_format
• gen_ai.openai.request.json_schema.name
• gen_ai.openai.request.service_tier
• gen_ai.openai.response.service_tier

Adds an openai.md document to outline the attributes that should be added to spans in addition to the general attributes. It also outlines the attributes which should be added to generative AI metrics.

Merge requirement checklist

• CONTRIBUTING.md guidelines followed.
• Change log entry added, according to the guidelines in When to add a changelog entry.
  • If your PR does not need a change log, start the PR title with [chore]
• schema-next.yaml updated with changes to existing conventions.

[drewby]

I'm creating this as Draft since its the first vendor specific conventions we are adding to the gen_ai area.
For spans, its a list of the new attributes for OpenAI and the general attributes combined.
For metrics, its only the OpenAI attributes and refers to the general metric document for other attributes.

• Should these be in one file or separate files for metrics and spans?
• Should it be a combined list of openai and general attributes, or only the openai attributes that get added?

[lmolkova]

Thank you! Left some comments

[lmolkova]

I've sent a similar one for Azure AI Inference - #1393 (without metrics though - no plans to report anything custom there yet).

Should these be in one file or separate files for metrics and spans?

Either way works for me. I'd keep them in one file until it grows too big.

Should it be a combined list of openai and general attributes, or only the openai attributes that get added?

Yes, the point is to describe all attributes that are applicable (and how if it's not obvious). Otherwise it's not clear which generic ones apply to openai.

[drewby]

Yes, the point is to describe all attributes that are applicable (and how if it's not obvious). Otherwise it's not clear which generic ones apply to openai.

Thanks, I brought this up in the Azure inference list as well, but is there a way to highlight, sort, or otherwise make it clear which ones are specific to openai? One can scan the list and fine the namespaces, but it'd be easier if they stood out visually.

[karthikscale3]

Looks good to me. Thanks @drewby

[codefromthecrypt]

Only glitch is service tiers, and I wonder if there would be difference vs OpenAI the platform vs Azure OpenAI. Certainly emulators would have differences. Should we mention the openai api docs, but caution that platform differences apply in exact values?

[lmolkova]

Left some minor comments, but LGTM overall!