Importing modules from a virtual environment in Python

Question

I've recently become interested in virtual environments in Python, in order to keep my code more organized and more portable. For this reason, I did a factory reset on my Raspberry Pi and started from scratch, with only the default Python modules. Beforehand I had made a list of all the dependencies for my project and their versions, and I installed them into a newly made virtual environment. Here's an example of how I did that in terminal, beginning in my project directory. (I'm hoping this is relevant to the question).

millertime@raspberrypi:~/Desktop/Project $ python3 -m venv venv
millertime@raspberrypi:~/Desktop/Project $ source venv/bin/activate
(venv) millertime@raspberrypi:~/Desktop/Project $ pip3 install mutagen==1.45.1
Looking in indexes: https://pypi.org/simple, https://www.piwheels.org/simple
Collecting mutagen==1.45.1
  Using cached https://www.piwheels.org/simple/mutagen/mutagen-1.45.1-py3-none-any.whl (218 kB)
Installing collected packages: mutagen
Successfully installed mutagen-1.45.1
(venv) millertime@raspberrypi:~/Desktop/Project $ deactivate

My main.py file and my virtual environment are in the same directory, yet when I try and import one of the modules I installed in my virtual environment, I get an error.

Traceback (most recent call last):
  File "/home/millertime/Desktop/Project/test.py", line 1, in 
    import mutagen
ModuleNotFoundError: No module named 'mutagen'

The same thing happens with all the other libraries I put in the virtual environment, except for Pygame and Pillow. I believe this to be because different versions of these came preinstalled with Python. As well, I can import os, random and anything else installed globally in Python.

This leads me to the question, how do I allow my python program to import modules contained in the virtual environment? I am using Python 3.9 on a Raspberry Pi 4.

user_11502612 · Answer

You should do the steps in the good order to use the Virtual Environment:

Creating the VENV
Source the venv/bin/activate
Install the required modules to the VENV
Call your script
Deactivate the VENV

I have tested the mutagen module in my VENV and it works as expected.

The used commands whit some commands:

# Creating the VENV
>>> python3 -m venv venv

# Sourcing the "activate" file.
>>> source venv/bin/activate

# Verify if the Python is used from VENV.
>>> which python3
/repo/user/venv/bin/python3

# Install the "mutagen" module to VENV.
>>> pip3 install mutagen==1.45.1
Collecting mutagen==1.45.1
  Downloading https://files.pythonhosted.org/packages/16/b3/f7aa8edf2ff4495116f95fd442b2a346aa55d1d46313143c8814886dbcdb/mutagen-1.45.1-py3-none-any.whl (218kB)
    100% |████████████████████████████████| 225kB 7.3MB/s 
Installing collected packages: mutagen
Successfully installed mutagen-1.45.1
You are using pip version 10.0.1, however version 21.3.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.

# Try to use the "mutagen" in the console (It worked perfectly).
>>> python3
Python 3.6.6 (default, Aug 24 2018, 09:30:17) 
[GCC 4.8.2] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import mutagen

# Deactivate the VENV (After this the Python will be used from OS not from VENV)
>>> deactivate

Importing modules from a virtual environment in Python

1 Answers