Configure Python Environment to Use Virtualenvwrapper

Working on a python project in an isolated python environment is recommended so that python modules and packages don’t meddle with that of other projects or even that of the operating system. Thus, a virtual environment is needed eminently.

I will show you how to set up your python environment to use virtualenvironment wrapper in Ubuntu 20.04. In this simple tutorial, we will do four things:

• Install pip3
• Install virtualenv
• Install virtualenvwrapper
• Edit .bashrc/ file or .bash_profile file, or both

Setting Up a Virtual Environment

We will use pip3, the default python package installer for Python3. Open your terminal in your home directory (or any other directory you may choose).

First, you need to create a special directory which will be hidden that will store all your virtual environments. We will do so as follows:

$ mkdir .virtualenv 
# the dot(.) denotes that the file is hidden

Install pip3:

$ sudo apt install python3-pip

Confirm installation of pip3:

$ pip3 --version # checks for the version of pip3
$ which pip3 # shows you the location of pip3 in your system

Install virtualenv using pip3:

$ pip3 install virtualenv # install virtualenv
$ which virtualenv # find where it is located

Now, it is time to install virtualenvwrapper:

$ pip3 install virtualenvwrapper

We will modify our .bashrc file by adding a row that will adjust every new virtual environment to use Python3. We will need to point virtual environments to the directory we created above (.virtualenv)

Open the .bashrc file using your vim editor:

$ vim .bashrc

If you notice that you do not have vim in your system, make sure you install it through $ sudo apt install vim

.bashrc file will open in your terminal. Something you should note about the vim editor is that it does not use the conventional editing commands such as ctrl + C etc. Rather, it uses its own special commands to allow you interact with it. Learn how to navigate the vim editor here.

For now, there are two basic commands you need to know:

• How to enter into insert mode so you can make edits
• How to save and quit

Now that your editor is open, we need to start making changes. Scroll to the bottom of the file by pressing the down arrow key. At the very bottom of your editor, press the letter i to enter into insert mode (i could mean 'insert').

Insert Mode

Add these rows:

#Virtualenvwrapper settings:
export WORKON_HOME=$HOME/.virtualenvs
VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3
. /usr/local/bin/virtualenvwrapper.sh

Save and Quit

Press esc and type :wq then press Enter This will allow you to save your changes and quit the editor. Close your terminal and reopen it.

Now you need to reload the bashrc script. There are two ways to do it:

1. Close and reopen the terminal
2. Execute this command in the terminal: source ~/.bashrc

You have completed setting up your virtual environment.

Create Your Virtual Environment

virtualenvwrapper allows you to create and activate your virtual environment at the same time. To create your virtual environment, use the command mkvirtualenv:

$ mkvirtualenv <name-of-your-virtual-environment> 
# for example mkvirtualenv chatapp

Your terminal will change from:

gitau@harry:~/software_development/python/flask_lesson_notes$

To something like:

(chatapp) gitau@harry:~/software_development/python/flask_lesson_notes$

To deactivate your virtual environment, run:

$ deactivate

Reactivate Your Virtual Environment

If you want to activate the virtual evironment you just created, run:

$ workon chatapp

workon command allows you to activate an already created virtualenvironment. You can also use the same command to list all available virtual environments in your system by running:

$ workon

Remove Your Virtual Environment

At some point, if you want to delete your virtual environment, simply use the rmvirtualenv command:

$ rmvirtualenv chatapp

Copy Your Virtual Environment

To copy an existing virtualevironment, use cpvirtualenv:

$ cpvirtualenv chatapp