Question

I am about to start learning Flask, and I’ve followed the installation instructions at http://flask.pocoo.org/docs/installation/#installation.

I’ve followed the virtualenv method, as opposed to the system wide installation. I just don’t understand what the structure of virtualenv and how it relates to Flask.

I ran all the commands in a directory. Does this mean that virtualenv, Flask and Jinga2 are all running in that very directory only? Does that mean I will need to set up virtualenv and flask every time I start a flask project in that project’s directory?

Secondly, When I navigate outside of the directory, my prompt still has venv. How can I stop that?

Answer 1

Virtualenv creates an isolated environment where you can install python packages without installing them globally on the system. After you run venv/bin/activate any new installed package is then inside this virtualenv (i.e. myproject/venv/lib) and if you exit the virtualenv then the system-wide python would not recognize the packages installed in virtualenv.

It doesn’t matter where you install packages using pip. When you executed virtualenv venv a folder called venv is created and all the installed packages will be copied there.

Finally, in order to exit the virtual environment simply run deactivate.