I am aware that there are many questions regarding Django and virtual environments, but I cannot wrap my head around the use of virtual environments with respect to deploying my Django app (locally) via uwsgi/nginx.

My setup includes a virtual environment (with Django and uwsgi), my Django app, nginx and PostgreSQL. The app was created before the virtual environment, and I applied only a single change to manage.py:

#!/Users/snafu/virtualdjango/bin/python3

When I start up the uwsgi located in the virtual environment (with the appropriate .ini file), everything works right away, but I wonder why. I did not need to fiddle around with the $PYTHONPATH, or append the site packages directory to the system path in manage.py, or activate the virtual environment at any point (apart from the initial installation of packages), although the boilerplate comment in manage.py explicitly mentions an inactive virtual environment as a possible reason for an import error.

CodePudding user response：

Activating a virtual environment does nothing but prepend the virtual environment's bin/ to the $PATH thus making python and pip without explicit paths running from the virtual environment. Everything else related to virtual environments is implemented inside Python — it automatically changes sys.path and other paths (sys.prefix, sys.exec_prefix, etc).

This means that when you run python with an absolute path from a virtual environment Python automatically activates the virtual environment for this particular Python session. So you don't need to activate the virtual environment explicitly.

There is a minor warning sign on the road though: to run any Python script from a non-activated virtual environment you must set the shebang for all scripts to point to the virtual environment or use sys.executable. Do not use explicit python because that could be a different Python from the $PATH.