Hynek Schlawack

Python appears to be everywhere nowadays!

Ever had this weird gut feeling that something is off in your code, but couldn’t put the finger on why?

Whenever I publish something about my Python Docker workflows, I invariably get challenged about whether it makes sense to use virtual environments in Docker containers.

Starting with 0.3.0, Astral’s uv brought many great features, including support for cross-platform lock files uv.lock.

One of my first TIL entries was about how you can imitate Node’s node_modules semantics in Python on UNIX-like operating systems.

When contributing to other users’ repositories, always start a new branch in your fork.

No, it’s not (just) run-parallel – let’s cut the local tox runtime by 75%!

Ever seen a code base where understanding a simple method meant jumping through tangled class hierarchies?

Ever since I got involved with open-source Python projects, tox has been vital for testing packages across Python versions (and other factors).

Why does DYLD_LIBRARY_PATH keep disappearing!?

A love letter to tools that changed everything for me.

One of my (slowly evaporating) reasons why I like putting packaging metadata into an executable setup.py is the ability to have optional dependencies that are combinations of others.

A common issue when writing tests for real-world software is how to deal with third-party dependencies.

An attempt at catharsis.

Codecov’s unreliability breaking CI on my open source projects has been a constant source of frustration for me for years.

Trying out something new: today I’m launching my own Today I Learned section.

The conflict between subclassing and composition is as old as object-oriented programming.

This post is less about teaching and more about schadenfreude amusement for you, and catharsis for me.

The widely used Python package cryptography changed their build system to use Rust for low-level code, which caused an emotional GitHub thread.

Lie and lay are infamously confusing to non-native speakers.

One of the main appeals of using Python’s asyncio is being able to fire off many coroutines and run them concurrently.

Let’s talk about abstractions and Pythonic code.

Some projects have the policy that all tests must have an explanatory comment – including all of mine.

GitHub’s own CI called GitHub Actions has been out of closed beta for a while and offers generous free quotas and a seamless integration with the rest of the site.

I’m missing a key part from the public Python discourse and I would like to help to change that.

Since this topic keeps coming up, I’d like to briefly share my thoughts on Python package metadata because it’s – as always – more complex than it seems.

People always ask for book recommendations, so here’s my list of books that changed my life in one way or another.

Since the acquisition of Travis CI, the future of their free offering is unclear.

There are many good reasons not to go to every talk possible when attending conferences.

PyPI is a gold mine of great packages but those packages have to be written first.

We have more ways to manage dependencies in Python applications than ever.

The DevOps movement gave us many ways to put Python applications into production.

Most Python programmers don’t spend a lot of time thinking about how equality and hashing works.

Proper cleanup when terminating your application isn’t less important when it’s running inside of a Docker container.

I’ve seen quite a bit of the world thanks to being invited to speak at conferences.

No matter whether you run a web app, search for gravitational waves, or maintain a backup script: reliability of your systems make the difference between sweet dreams and production nightmares at 4am.

The Python standard library is full of underappreciated gems.

If your Python decorator unintentionally changes the signatures of my callables or doesn’t work with class methods, it’s broken and should be fixed.

To get real time insight into running applications you need to instrument them and collect metrics: count events, measure times, expose numbers.

Since the inception of wheels that install Python packages without executing arbitrary code, we need a static way to encode conditional dependencies for our packages.

My completely anecdotal view on the state of Python 3 in 2016.

Don’t use Python’s hasattr() unless you’re writing Python 3-only code and understand how it works.

Why “Use bcrypt.” is not the best recommendation (anymore).

How to ensure that your tests run code that you think they are running, and how to measure your coverage over multiple tox runs (in parallel!).

Your Python applications are running but you’re wondering what they are doing?

Setting up Python to the point to be able install packages from PyPI can be annoying and time-intensive.

TLS is the best technology we have for securing our communications.

Apple ships a patched version of OpenSSL with macOS.

A completely incomplete guide to packaging a Python module and sharing it with the world on PyPI.

Google killed its Reader and my beloved Reeder for Mac and iPad officially won’t get updated in time.