How do I keep updates to Blender's Python install when I want to use a new version of Blender?

Question

I'm on macOS with a new install of Blender, current version as of now. I had some issues and finally managed to get pip working with the Blender install of Python and I'm adding modules I need to use in some scripts. (Such as Pillow, for adding ID info on rendered images then saving the blended images as PNGs.) So I have special modules set up in that instance of Python, which is entirely within the main Blender directory, in /Applications/Blender.

When I upgrade to a newer version of Blender, on Mac, that's generally done by drag-and-drop, which would lead to replacing everything in the old Blender install.

Is there a preset way to handle this that lets me install the new Blender and keeping the modules I've added to that Python install? Or do I just need to keep a record of what modules I add so when I get a new version of Blender, I can re-install pip and re-add all the modules I've added?

Answer 1

Yes you will need to have a backup setup script which you have to manually keep and maintain that when executed will install ensurepip, pip, enable built-in addons, and install the third party addons, etc. Basically it would look something like the following script which you execute everytime you have a new Blender install:

import subprocess
import sys
import os

python_exe = os.path.join(sys.prefix, 'bin', 'python.exe')

# install pip
subprocess.call([python_exe, '-m', 'ensurepip'])
subprocess.call([python_exe, '-m', 'pip', 'install', '--upgrade', 'pip'])

# Install Python Modules/Libraries/Packages
subprocess.call([python_exe, '-m', 'pip', 'install', '--upgrade', 'PACKAGE_NAME_1'])
subprocess.call([python_exe, '-m', 'pip', 'install', '--upgrade', 'PACKAGE_NAME_2'])
subprocess.call([python_exe, '-m', 'pip', 'install', '--upgrade', 'PACKAGE_NAME_3'])

# Enable built-in addons
# Enable addon 1
# Enable addon 2
# Enable addon 3

# Install third party addons
# Install addon 1
# Install addon 2
# Install addon 3

You can find more info here:

• pip installation: How to install Pip for Blender's bundled Python?
• enabling addons: How to enable and disable Add-ons via Python?
• installing addons here: How to Install Multiple Add-ons with Python Script