[tutorial] PEX Unpacked: Building and Executing Python Executables with Ease

What is “PEX”?

The full name of PEX is Python Executable. This is an open-source tool for building a virtual environment to execute your Python code. However, be cautious when using PEX because it does not include a Python interpreter; thus, your computer must have a Python environment installed.

The process of executing .pex

When you run a .pex file, the system reads the shebang line at the top of the file, #!/usr/bin/env python, to invoke the Python interpreter to execute the script.

Practice

Install PEX

pip install pex

Enter Interpretable pex environemt

Easy way

# Enter an interpretable Pex environment without specifying a Python version
pex 

# Enter an interpretable Pex environment specifying a specific Python version
pex --python=python3.12 # specific python version

---
Pex 2.16.1 ephemeral hermetic environment with no dependencies.
Exit the repl (type quit()) and run `pex -h` for Pex CLI help.
Python 3.11.4 (main, Jul  5 2023, 08:40:20) [Clang 14.0.6 ] on darwin
Type "help", "pex", "copyright", "credits" or "license" for more information.
>>> 

Advanced

# Specifying requirements
pex pandas

---
Pex 2.16.1 ephemeral hermetic environment with 1 requirement and 6 activated distributions.
Python 3.11.4 (main, Jul  5 2023, 08:40:20) [Clang 14.0.6 ] on darwin
Type "help", "pex", "copyright", "credits" or "license" for more information.
>>> import pandas as pd

Package .py into pex file

# demo.py

import pandas as pd

def main():
    print(f"Hello, World! The pandas version is {pd.__version__}")

if __name__ == "__main__":
    main()

pex -D . -e demo:main -o demo.pex -r requirements.txt

# Execute PEX script
./demo.pex

>>> Hello, World! The pandas version is 2.2.2

• -D: Source directory
• -e: Entry point for the PEX application
• -o: Output file name for the PEX file
• -r: Specifies requirements file that lists the dependencies

Reference

• 探索PEX：高效且可移植的Python环境解决方案
• Specifying entry points