dify - 💡(How to fix) Fix Support custom OpenInference session.id for Service API tracing [1 participants]

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1. Is this request related to a challenge you're experiencing? Tell me about your story.

In enterprise deployments, Dify is often used as an application engine and integrated primarily through the Service API rather than through the built-in Web or Console UI.

Tracing data is commonly collected by third-party observability platforms, for example Arize Phoenix. These platforms often use the OpenInference semantic convention session.id to group related traces into a logical user/session view.

Today, when calling Dify workflows or chatflows through the Service API, callers do not have a first-class way to provide their own tracing session identifier. This makes it difficult to align Dify traces with the enterprise system's existing session, request, tenant, or user journey identifiers in Phoenix or other OpenInference-compatible tracing backends.

It would be useful if Dify supported an optional way to customize the tracing session ID when invoking apps via the Service API, for example through a request parameter such as trace_session_id or through an HTTP header. This value should only affect the exported tracing attribute, such as OpenInference session.id, and should not create or resume a Dify conversation by itself.

Related version/context: Dify 1.14.1.

I've gone ahead creating a demo patch based on Dify 1.6, this video should explain the concept:

https://github.com/user-attachments/assets/543d409d-3cfe-4795-93fe-5fa001272746

2. Additional context or comments

A possible behavior could be:

• Service API callers may pass an optional tracing session override, either in JSON body or header.
• Tracing providers that understand OpenInference semantics, such as Phoenix, can export it as session.id.
• If the caller does not provide the value, Dify keeps the current default session behavior.
• The custom tracing session ID remains an observability concern and does not alter conversation_id, workflow run IDs, OpenTelemetry trace IDs, or span parent/child relationships.

3. Can you help us with this feature?

• I am interested in contributing to this feature.