fix: Logging fix for python 3.13

[gavin-aguiar]

Problem Description

In Python 3.13 Azure Functions, user logs were not appearing in the function execution logs. This was because the proxy_worker implementation was missing the invocation ID context setup that is required for proper log correlation.

Root Cause Analysis

The issue was specific to Python 3.13 because:

• Python 3.12 and below: Uses azure_functions_worker directly which properly sets up invocation context
• Python 3.13: Uses proxy_worker that delegates to runtimes/v2 library worker, but the proxy wasn't bridging the invocation context

The library worker uses thread-local storage for invocation ID tracking, but the proxy worker wasn't setting up this context, causing all user logs to appear without invocation IDs and thus not show up in the function logs.

Fixes #

---

Pull Request Checklist

Host-Worker Contract

• Does this PR impact the host-worker contract (e.g., gRPC messages, shared interfaces)?
  • If yes, have the changes been applied to:
    • azure_functions_worker (Python <= 3.12)
    • proxy_worker (Python >= 3.13)
  • If no, please explain why:

Worker Execution Logic

• Does this PR affect worker execution logic (e.g., function invocation, bindings, lifecycle)?
  If yes, please answer the following:

Python Version Coverage

• Does this change apply to both Python <=3.12 and 3.13+?
• If yes, have the changes been made to:
  • azure_functions_worker (Python <= 3.12)
  • runtimes/v1 / runtimes/v2 (Python >= 3.13)
• If no, please explain why:

Programming Model Compatibility (for Python 3.13+)

• Does this change apply to both:
  • V1 programming model (runtimes/v1)?
  • V2 programming model (runtimes/v2)?
• Explanation (if limited to one model):

[ayelencasamassa]

Hi, I'm still having this issue, how am i supposed to apply fix?
Thanks.

[hallvictoria]

Hi @ayelencasamassa, the fix has been released as part of runtime version 4.1043, which is currently rolling out. ETA to reach all regions is end of September / early October.

If you need the fix immediately, you can create a function app in one of the following regions: East Asia, West Central US, North Europe, or West US 2.

[ayelencasamassa]

Hi @ayelencasamassa, the fix has been released as part of runtime version 4.1043, which is currently rolling out. ETA to reach all regions is end of September / early October.

If you need the fix immediately, you can create a function app in one of the following regions: East Asia, West Central US, North Europe, or West US 2.

Hello, any news on this? Is there any way I can check roll out to Canada?
Thanks.

[hallvictoria]

Hi @ayelencasamassa, this has been rolled out to all regions. You can view the runtime version in the portal, and you may need to restart your app to pick up 4.1043.

If you're still facing issues, please open an issue and we can follow up there.