📝 Update Gunicorn guide to use uvicorn-worker library

[siavashyj]

Update FastAPI Server Workers Documentation

Description

This PR updates the FastAPI Server Workers documentation to reflect the changes in Uvicorn worker implementation. The uvicorn.workers.UvicornWorker has been deprecated as of Uvicorn version 0.30.0, and we're now recommending the use of the uvicorn-worker package.

Changes

• Updated installation instructions to include the uvicorn-worker package
• Changed references from uvicorn.workers.UvicornWorker to uvicorn_worker.UvicornWorker
• Updated the explanation of the --worker-class option to reflect the new import

Rationale

These changes are necessary to keep our documentation up-to-date with the latest best practices for deploying FastAPI applications with Gunicorn and Uvicorn workers.

Testing

• Verified that the installation instructions work with the latest versions of the packages
• Tested the Gunicorn command with the new worker class
• Ensured that the document flow and overall structure remain intact

Additional Notes

Users upgrading from an older version may need to update their deployment scripts to use the new uvicorn_worker.UvicornWorker class. We may want to consider adding a migration guide or note in the documentation to help with this transition.

[tiangolo]

📝 Docs preview for commit 98c1c8d at: https://af3405bf.fastapitiangolo.pages.dev

[tiangolo]

📝 Docs preview for commit 5b057ce at: https://9afd07f2.fastapitiangolo.pages.dev

[siavashyj]

Ready to merge 🟢

[Kludex]

My recommendation is to remove Gunicorn from the documentation.

[siavashyj]

My recommendation is to remove Gunicorn from the documentation.

I've had some not-so-great experiences running native Uvicorn workers on production instances due to: 1-potential memory leaks on long running instances, 2-slightly lower performance, 3-and higher tendency to timeout (502) under load compared to Gunicorn-Uvicorn workers.

I think keeping it as an option is still a good thing to have, especially for long running production instances.
What do you think @Kludex?

[KissPeter]

My recommendation is to remove Gunicorn from the documentation.

I've had some not-so-great experiences running native Uvicorn workers on production instances due to: 1-potential memory leaks on long running instances, 2-slightly lower performance, 3-and higher tendency to timeout (502) under load compared to Gunicorn-Uvicorn workers.

I think keeping it as an option is still a good thing to have, especially for long running production instances. What do you think @Kludex?

I can proof it with measurements:
https://kisspeter.github.io/fastapi-performance-optimization/workers_and_threads#gunicorn-vs-uvicorn

[Kludex]

When did you do that?

Also... There's no need to prove anything here.

[github-actions]

📝 Docs preview for commit 8aa7fcc at: https://843d246e.fastapitiangolo.pages.dev

Modified Pages

• https://843d246e.fastapitiangolo.pages.dev/deployment/server-workers/

[estebanx64]

Hi @siavashyj

Thanks for your time and for helping us handle this topic. 🙇

We have planned to change these docs soon and we'll be reviewing it! 🤓

[github-actions]

📝 Docs preview for commit 431679a at: https://f8afe6c3.fastapitiangolo.pages.dev

Modified Pages

• https://f8afe6c3.fastapitiangolo.pages.dev/deployment/server-workers/

[tiangolo]

Thanks for the interest @siavashyj!

I prefer to recommend the new Uvicorn with --workers, it's fewer moving parts, simpler code, and fewer chances of having errors and problems. 🤓

I updated the docs here: #12069, that should cover this.

I'll now close this one, but thanks for the effort! ☕