The Python Enchiridion

Enchiridion: A small manual or handbook. It's a bit like a tech cook book, but a bigger, fancier, SEO-optimizabler word.

Links to python resources, examples, setup and temporary scripts.

Building and running

# Setting up and using virtualenv.
python -m venv env/
source env/bin/activate
pip install --upgrade pip

./setup.py test

# Create a distribution
pip install wheel
./setup.py sdist bdist_wheel

# Install from repo
./setup.py install

# Or install from wheel
pip install dist/python_scripts-*.whl

# After installing, you can run the script.

# Print usage instructions
hello-world --help

# Run a server.
hello-world                 # prints Hello, World!
hello-world --name=comrade  # prints Hello, comrade!

Testing and automation

Black: The uncompromising code formatter

pip install black
black bin/* scanscan/ tests/ setup.py 

Flake8: Your Tool For Style Guide Enforcement

pip install flake8
flake8 bin/* scanscan/ tests/ setup.py

Nose is nicer testing for python

Nose appears to be unmaintained since 2016.

pip install nose
nosetests -v

pytest helps you write better programs

pip install pytest
pytest -v

Tox: standardize testing in Python

See tox.ini.

pip install tox
tox --skip-missing-interpreters

IntelliJ setup

• IntelliJ
  • Using the Python plugin
  • Set up a Python SDK virtualenv in $PROJECT/env

Running in docker

docker run -it --volume $PWD:/opt/workdir --workdir /opt/workdir python:3.6 bash

Syntax and best practices

• Object-oriented programming

  • Language Reference - Data Model
  • Python in a Nutshell - Object oriented
  • Understanding Object Instantiation and Metaclasses in Python

• PEP

  • PEP 8 -- Style Guide for Python Code
  • PEP 257 -- Docstring Conventions
  • PEP 440 -- Version Identification and Dependency Specification

Standard modules

• The ast module (doc, tests) - Abstract Syntax Trees

  • Scary example code:
    • Scary1: has some good discussion on how to sanitize
    • Scary2
    • Scary3
  • Tutorial - Dynamic Python
  • Better docs

• The dataclasses module (doc, [PEP 557], tests) - Data Classes

• The datetime module (doc, tests) - Basic date and time types

• The http.server module (doc) - HTTP servers

• The logging module (doc, tests) - Logging facility for Python

• The re module (doc, tests) - Regular expression operations

• The socket module (doc, tests) - low-level networking interface

  • Tutorial - Python sockets
  • Unix domain sockets

• The socketserver module (doc, tests) - A framework for network servers

• The unittest module (doc) - Unit testing framework

[PEP 557]: https://peps.python.org/pep-0557/ [PEP 557 - Data Classes]

Project packaging and setup

How do you set up a project again? What are all of those files for?

• How To Package Your Python Code
• Hitchhiker's Guide - Structuring Your Project
• Python packaging - Past, Present, Future (Feb 2019)
• Example code:
  • https://github.com/pypa/sampleproject
  • https://github.com/navdeep-G/samplemod
• How to make an awesome Python package in 2021
• How to create a Python package in 2022

Files:

• .gitignore: Lots of examples of temporary and build files generated during the software lifecycle.
• LICENSE (ASL-2): How you want your software used and distributed. See also setup.py
• MANIFEST.in: Files included in the source distribution
• README.md: This file, used in github but also in the distributed package.
• setup.py : Build python projects.
• tox.ini : Used for coordinating builds and tests with tox.

PyPI (the Python package index)

• Package index mirrors and caches

You can create a PyPI mirror like this:

# In one virtual env, download a package and put it in the mirror.
pip install piprepo
pip download --destination-directory /tmp/cache avro-python3==1.9.2 # Fails
pip download --destination-directory /tmp/cache avro-python3==1.9.2.1 
pip download --destination-directory /tmp/cache avro-python3==1.10.0 
pip download --destination-directory /tmp/cache avro-python3==1.10.1 
pip download --destination-directory /tmp/cache avro-python3==1.10.2 
pip download --destination-directory /tmp/cache avro-python3
pip download --destination-directory /tmp/cache wheel
pip download --destination-directory /tmp/cache pycodestyle
piprepo build /tmp/cache/
# The directory is now a cache of all the Avro packages

# In any other virtualenv, use the mirror.
pip install -i file:///tmp/cache/simple --force-reinstall avro-python3

# Or use a docker to isolate the installation.
docker run -it -v /tmp/cache/:/tmp/cache --network none python:3 \
    pip install -i file:///tmp/cache/simple --force-reinstall avro-python3