Switch from the Flask server to another web server

While lightweight and easy to use, Flask’s built-in server is not suitable for production as it doesn’t scale well.
Upsun supports several different web servers for Python that you can use instead. Choose your server depending on your app and specific requirements.

The following instructions allow you to switch to Gunicorn. If you choose another web server, you may need to take different steps.

To switch to Gunicorn web server, follow these steps:

1. Open your .upsun/config.yaml file, and locate the section dedicated to the web server:

   .upsun/config.yaml

   web:
     commands:
       start: "flask run -p $PORT"
     upstream:
       socket_family: tcp

   Change the start command:

   .upsun/config.yaml

   web:
     # Commands are run once after deployment to start the application process.
     commands:
       # The command to launch your app. If it terminates, it’s restarted immediately.
       # You can use the $PORT or the $SOCKET environment variable depending on the socket family of your upstream
       start: "gunicorn -w 4 'autoapp:app'"

2. Commit your changes and push them to your environment. To do so, run the following commands:

   Terminal

   git add .upsun/config.yaml
   git commit -m "Changes project to use Gunicorn"
   upsun environment:push -y

Next steps

• Set up a more robust local development environment
• Add a source control integration
• Add various services to your project