Support Dynamic Headers in Otel Traces and Langfuse API calls

[tw-dpd]

Describe the feature or potential improvement

Support Dynamic Headers in Otel Traces and Langfuse API Calls

• would allow the Langfuse instance to be hosted behind authenticating proxies (such as Google's GCP Identity Aware Proxy)
• would allow for any header value to be set on both the Otel trace header and API Calls for any other purposes a deployment may have beyond just dynamic authentication headers.

Additional information

Adding this feature would allow users to deploy Langfuse behind an authenticated proxy and not have to expose Langfuse to the public internet directly - significantly improving the security of a deployment and allowing additional customers to deploy that may have been put off by the thought of exposing a Langfuse instance in this way.

[tw-dpd]

Pull Request for Feature in Python library: langfuse/langfuse-python#1318
Feature request for Terraform GCP support: langfuse/langfuse-terraform-gcp#7

[hassiebp]

Thanks for opening this Github idea - @tw-dpd !

[Lemmons]

I'm very interested in this option. It is not uncommon for companies to have their own internal auth system and currently langfuse forces them to publicly expose deployments which otherwise could be internal only, or to settle for running no authz/rbac, which is a non-starter.

[frankcaoyun]

Hi, we have the same interest to host langfuse inside an internal network on GCP. Really look forward to a proper solution to move this forward!

[tw-dpd]

Hi @frankcaoyun, i raised a feature request for this as Langfuse stated they had no interest from users in this and would not accept the PR
langfuse/langfuse-terraform-gcp#7

[frankcaoyun]

Hey @tw-dpd thanks for the reply. The PR looks like it's introducing the additional IAP authentication layer that adds the complexity where original langfuse already support SSO. I was just looking for a solution for deployment in the internal company network on GCP with no app-side logic needs to be changed, perhaps that would be a smaller change to manage if possible. Anyways thanks for the reply!