Python - Environment Management
Virtual Environments
These let you install Python modules in a local directory instead of system-wide. Use them!
Reasons:
- Keep your system files clean
- Keep projects from conflicting with each other
- More consistent across developer setups
Create
$ python -m venv ./venv
Activate
Mac and Linux:
$ source venv/bin/activate
Windows:
$ venv/Scripts/activate.bat # Terminal
$ venv/Scripts/Activate.ps1 # Powershell
Your terminal prompt should now have (venv) at the start. Now pip modules will install locally!
Deactivate
$ deactivate
Requirements
The best way to track dependencies is to manually create a requirements.txt file, then add all packages you install into that file first before installing them. It’s also a good idea to use the ~= “compatible release” version specifier.
Quick and dirty way:
# Dump current requirements into a file
$ pip freeze > requirements.txt
# Install requirements from file
$ pip install -r requirements.txt
Tip
Most IDEs - like PyCharm - can automatically use virtual environments and generate the requirements.txt file.
The requirements file provides an easy way to keep a list of module dependencies, and allow different developers to configure the same environment.