Description

Taking inspiration from traceloop's openllmetry support for langchain instrumentation, added callback handler support for llm start and end to generate span with attributes listed here.

Attributes added on span:
-> gen_ai.operation.name: Str(chat)
-> gen_ai.system: Str(ChatOpenAI)
-> gen_ai.request.model: Str(gpt-3.5-turbo)
-> gen_ai.request.top_p: Double(0.9)
-> gen_ai.request.frequency_penalty: Double(0.5)
-> gen_ai.request.presence_penalty: Double(0.5)
-> gen_ai.request.stop_sequences: Slice(["\n","Human:","AI:"])
-> gen_ai.request.seed: Int(100)
-> gen_ai.request.max_tokens: Int(100)
-> gen_ai.provider.name: Str(openai)
-> gen_ai.request.temperature: Double(0.1)
-> gen_ai.response.finish_reasons: Slice(["stop"])
-> gen_ai.response.model: Str(gpt-3.5-turbo-0125)
-> gen_ai.response.id: Str(chatcmpl-Bz8yrvPnydD9pObv625n2CGBPHS13)
-> gen_ai.usage.input_tokens: Int(24)
-> gen_ai.usage.output_tokens: Int(7)

Please refer complete span attributes o/p: https://docs.google.com/document/d/13SXuf4iZSl2MqWUJtmoDEqFxuHZ1Y8hykW_ctlykcDE/edit?tab=t.0

We have just added span support in this PR for now to keep this PR concise and in future we will have metric and log support PRs.

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• From test folder /opentelemetry-python-contrib/instrumentation-genai/opentelemetry-instrumentation-langchain/tests run pytest -rP test_llm_call.py

Does This PR Require a Core Repo Change?

• Yes. - Link to PR:
• No.

Checklist:

See contributing.md for styleguide, changelog guidelines, and more.

• Followed the style guidelines of this project
• Changelogs have been updated
• Unit tests have been added
• Documentation has been updated