Add Support for Custom Headers in LLM Requests

[k1ng]

Feature Description

To integrate and proxy requests from Zep through Portkey.ai, we need the ability to add custom headers to our requests to the LLM. Please note that Portkey.ai already has an integration with Langchain.

Portkey.ai requires certain specific headers to be passed in every API call, which can be found in their documentation: https://docs.portkey.ai/how-portkey-works/portkey-headers

Value of Feature

This feature will allow logging Zep's requests to LLM and calculating the cost of LLM calls as a part of Zep-Portkey.ai integration. Custom headers support could also be useful for other potential integrations and use-cases.

Possible Implementation

We could provide the ability to set custom headers through environment variables, a .env file, or the config.yaml file. This provides flexibility in choosing how to supply custom headers, depending on user preferences or security requirements.

Thank You.