Gunicorn

Basic Usage

Gunicorn is the wsgi server used by Talisker. To use it, simply use the Talisker wrapper in place of regular gunicorn script.

$ talisker.gunicorn -c config.py myapp:wsgi_app

This wrapper simply initialises Talisker before passing control to Gunicorn’s entrypoint. As such, it takes exactly the same command line arguments, and behaves in the same way.

Talisker supports the sync, gevent, and eventlet workers. Others workers may work, but have not been tested. The only place it matters is in the context-local storage of Talsiker log tags and request ids. Talisker will use greenlet based contexts if it finds itself running in a greenlet context, or else a thread local object.

Python 3.6, Async and Requests

Due to changes in the SSL api in python 3.6, requests currently has a bug with https endpoints in monkeypatched async context. The details are at https://github.com/requests/requests/issues/3752, but basically the monkeypatching must be done before requests is imported. Normally, this would not affect gunicorn, as your app would only import requests in a worker process after the monkeypatch has been applied. However, because Talisker enables some integrations in the main process, before the gunicorn code is run, it triggers this bug. Specfically, we import the raven library to get early error handling, and raven imports requests.

We provide two special entrypoints to work around this problem, if you are using python 3.6 and eventlet or gevent workers with the requests library. They simply apply the appropriate monkeypatching first, before then just initialising talikser and running gunicorn as normal.

$ talisker.gunicorn.eventlet --worker-class eventlet -c config.py myapp:wsgi_app

$ talisker.gunicorn.gevent --worker-class gevent -c config.py myapp:wsgi_app