Setup Virtualenv for Any Project

• Virtualenv is a very handy tool for creating separate virtual environments for python projects.
• It is essential and probably mandatory in many cases to use Virtualenv or Virtualenv-like tools (i.e. Anaconda, Pipenv) to run a python project.
• In this tutorial, I'll show you how to create a virtualenv for a python project step-by-step.

NOTE: the commends in this tutorial is for Linux/Mac OS, Windows will be slightly different when setting up environment variables and system path

Setup virtualenv

1. Install pip

• sudo apt-get install python-pip

2. Install virtualenv

• sudo pip install virtualenv

3. Create a folder to install virtualenv

• Normally this folder would be created inside the project folder
  • For example, inside the Projects folder
• It should be named as Envs

4. Install virtualenvwrapper

• sudo pip install virtualenvwrapper
• This is a very useful tool/package to save you from the hassles of virtualenv

5. Set WORKON_HOME to your virtualenv

• export WORKON_HOME=~/Desktop/Projects/Env
• If the virtualenv folder is located at the root directory, use:
  • export WORKON_HOME=~/.Env

6. Add virtualenvwrapper.sh to .bashrc (NOTE its .zshrc on Mac)

• Navigate to the folder where the virtualenv is installed (normally under /usr/local/bin)
• nano ~/.bashrc (nano ~/.zshrc on Mac)
• Add the following line to the folder:
  • source /usr/local/bin/virtualenvwrapper.sh
• If the virtualenvwrapper is installed in another directory, add the path of the directory instead of the /usr/local/bin/
  • For example, . /Users/Carson/anaconda3/bin/virtualenvwrapper.sh
• CTRL + X to exit, and Y to save, and hit Enter
• After its being added, use source ~/.bashrc (source ~/.zshrc on Mac) to check if it is working. It should print some files on the screen with no errors
  • NOTE if there is a path issue for virtualenv or python path (i.e. there are multiple versions of Python in system), use which python to find the path, and then add VIRTUALENVWRAPPER_PYTHON=<python path> to the bashrc/zshrc

Setup virtual environment

1. make virtual environment

• mkvirtualenv env_name --python=python3
• check python version: python -V

2. activate environment

• the environment is activated by default when created
• to activate an environment: workon env_name

3. get the project

• navigate to the directory that you would like to download the project
• get the project: git clone
• From the directory you could tell which python version the project is under

4. get all the nesscary packages

• enter the project directory and nevigate to where the requirement file is located
• pip install -r requirements.txt

5. adding apps for the defaul path in virtualenv

• sometimes when installing the packages errors may occor, since the apps are put inside the apps folder which is not recognized by virtualenv
• add the apps folder: add2virtualenv apps

6. setup default startup folder for the environment

• navigate to the folder where you work all the time
• setup the folder as default: setvirtualenvproject
• once the default folder is setup, use cdproject to go back from anywhere

7. install dev tools:

• If the project has a different requirements file for the devs, navigate to that folder
• pip install -r /requirements/dev.txt

8. remove environment

• rmvirtualenv env_name

9. tell django which setting files to run in environment:

• the goal of this step is for the django to use the customized settings in the /project_name/settings/dev.py
• go to the folder where the manage.py locates
• copy the path generated: pwd
• go to the virtual environment: cdvirtualenv
• cd bin
• to enter and edit the file: nano postactivate
  • put the following lines below the comments:
    • export DJANGO_SETTINGS_MODULE='project_name.settings.dev'
    • export PYTHONPATH=$PYTHONPATH:'path_generated_by_pwd'
    • The first line allows you to use customized settings
    • The second line allows you to django-admin commands
  • close and save the file: ctrl + x, type y and press enter
• to enter and edit the file: nano postdeactivate
  • put the following lines below the comments:
    • unset DJANGO_SETTINGS_MODULE
• deactivate and activate the environment for the settings to work

10. start django project

• if you have done step 9: django-admin runserver
• if you haven't done step 9: python manage.py runserver

11. check the website in browser

• localhost:8000

12. Force refresh the browser

• Sometimes when working with multiple projects and switching back and forth, the page display in browser can be scattered since there is cache built-in the browser
• to force refresh the browser: ctrl + shift + r

13. Some useful virtualenv commands

• lsvirtualenv: List all of the environments.
• cdsitepackages: Navigate into the site-package directory of the currently activated virtual environment
• lssitepackages: Shows contents of site-package directory.