Python

A collection of 67 posts

C

Debugging C code on macOS

I started to write C 25 years ago now, with many different tools over the year. As many open source developers, I spent most of my life working with the GNU tools out there. As I've been using an Apple computer over the last years, I had to adapt to

Interview

Interview: The Performance of Python

Earlier this year, I was supposed to participate to dotPy [https://dotpy.io], a one-day Python conference happening in Paris. This event has unfortunately been cancelled due to the COVID-19 pandemic. Both Victor Stinner and me were supposed to attend that event. Victor had prepared a presentation about Python performances,

Python

Attending FOSDEM 2020

This weekend, I've been lucky to attend again the FOSDEM [https://fosdem.org/2020/] conference, one of the largest open-source conference out there. I had a talk scheduled in the Python devroom [https://fosdem.org/2020/schedule/track/python/] on Saturday about building a production-ready profiling in Python [https://fosdem.

Python

Python Logging with Datadog

At Mergify [https://mergify.io], we generate a pretty large amount of logs. Every time an event is received from GitHub for a particular pull request, our engine computes a new state for it. Doing so, it logs some informational statements about what it's doing — and any error that might

Python

Atomic lock-free counters in Python

At Datadog [https://datadog.com], we're really into metrics. We love them, we store them, but we also generate them. To do that, you need to juggle with integers that are incremented, also known as counters. While having an integer that changes its value sounds dull, it might not be

Python

Finding definitions from a source file and a line number in Python

My job at Datadog [https://datadog.com] keeps me busy with new and questioning challenges. I recently stumbled upon a problem that sounded easy but was more difficult than I imagined. Here's the thing: considering a filename and a line number, can you tell which function, method or class this

Python

Sending Emails in Python — Tutorial with Code Examples

What do you need to send an email with Python? Some basic programming and web knowledge along with the elementary Python skills. I assume you’ve already had a web app built with this language and now you need to extend its functionality with notifications or other emails sending. This

Python

Python and fast HTTP clients

Nowadays, it is more than likely that you will have to write an HTTP client for your application that will have to talk to another HTTP server. The ubiquity of REST API makes HTTP a first class citizen. That's why knowing optimization patterns are a prerequisite. There are many HTTP

Python

Dependencies Handling in Python

Dependencies are a nightmare for many people. Some even argue they are technical debt [https://thenewstack.io/to-reduce-tech-debt-eliminate-dependencies-and-refactoring/] . Managing the list of the libraries of your software is a horrible experience. Updating them — automatically? — sounds like a delirium. Stick with me here as I am going to help you get

Python

Handling multipart/form-data natively in Python

RFC7578 [https://tools.ietf.org/html/rfc7578] (who obsoletes RFC2388 [https://tools.ietf.org/html/rfc2388]) defines the multipart/form-data type that is usually transported over HTTP when users submit forms on your Web page. Nowadays, it tends to be replaced by JSON encoded payloads; nevertheless, it is still widely

Python

Advanced Functional Programming in Python: lambda

A few weeks ago, I introduced you to functional programming in Python [julien.danjou.info/python-and-functional-programming/]. Today, I'd like to go further into this topic and show you so more interesting features. Lambda Functions What do we call lambda functions? They are in essence anonymous functions. In order to create

Python

An Introduction to Functional Programming with Python

Many Python developers are unaware of the extent to which you can use functional programming in Python, which is a shame: with few exceptions, functional programming allows you to write more concise and efficient code. Moreover, Python’s support for functional programming is extensive. Here I'd like to talk a

Python

Writing Your Own Filtering DSL in Python

A few months ago, we've seen how to write a filtering syntax tree [https://julien.danjou.info/multi-value-syntax-tree-filtering-in-python/] in Python. The idea behind this was to create a data structure — in the form of a dictionary — that would allow to filter data based on conditions. Our API looked like this:

Python

Serious Python released!

Today I'm glad to announce that my new book, Serious Python, has been released. However, you wonder… what is Serious Python? Well, Serious Python is the the new name of The Hacker's Guide to Python — the first book I published. Serious Python is the 4th update of that book — but

Python

A multi-value syntax tree filtering in Python

A while ago, we've seen how to write a simple filtering syntax tree with Python [https://julien.danjou.info/simple-filtering-syntax-tree-in-python/]. The idea was to provide a small abstract syntax tree with an easy to write data structure that would be able to filter a value. Filtering meaning that once evaluated,

Python

The Best flake8 Extensions for your Python Project

In the last blog post about coding style [https://julien.danjou.info/code-style-checks-in-python/], we dissected what the state of the art was regarding coding style check in Python. As we've seen, Flake8 is a wrapper around several tools and is extensible via plugins: meaning that you can add your own

Python

Code Style Checks in Python

After starting your first Python project [https://julien.danjou.info/starting-your-first-python-project/], you might realize that it is actually not that obvious to be consistent with the way you write Python code. If you collaborate with other developers, your code style might differ, and the code can become somehow unreadable. I

Python

High-Performance in Python with Zero-Copy and the Buffer Protocol

Whatever your programs are doing, they often have to deal with vast amounts of data. This data is usually represented and manipulated in the form of strings. However, handling such a large quantity of input in strings can be very ineffective once you start manipulating them by copying, slicing, and

Python

Starting your first Python project

There's a gap between learning the syntax of the Python programming language and being able to build a project from scratch. When you finish reading your first tutorial or book about Python, you're good to go for writing a Fibonacci suite calculator, but that does not help you starting your

Python

A simple filtering syntax tree in Python

Working on various pieces of software those last years, I noticed that there's always a feature that requires implementing some DSL. The problem with DSL is that it is never the road that you want to go. I remember how creating my first DSL was fascinating: after using programming languages

Python

Correct HTTP scheme in WSGI with Cloudflare

I've recently been using Cloudflare [https://cloudflare.com] as an HTTP frontend for some applications, and getting things working correctly with WSGI was unobvious. In Python, WSGI [https://en.wikipedia.org/wiki/Web_Server_Gateway_Interface] is the standard protocol to write a Web application. All Web frameworks that I

Python

Is Python a Good Choice for Entreprise Projects?

A few weeks ago, one of my followers, Morteza, reached out and asked me the following: > I develop projects mostly with Python, but I am scared that Python is not a good choice for enterprise projects. In many cases, I've encountered a situation where Python performance was not sufficient, like

Ghost

On blog migration

I've started my first Web page in 1998 and one could say that it evolved quite a bit in the meantime. From a Frontpage designed Web site with frames, it evolved to plain HTML files. I've started blogging in 2003, though the archives of this blog only gets back to

Python

Scaling a polling Python application with tooz

This article is the final one of the series I wrote about scaling a large number of connections in a Python application. If you don't remember what the problem we're trying to solve is, here it is, coming from one of my followers: > It so happened that I'm currently working

Python

Scaling a polling Python application with asyncio

This article is a follow-up of my previous blog post about scaling a large number of connections [https://julien.danjou.info/scaling-python-application-threads]. If you don't remember, I was trying to solve one of my followers' problem: > It so happened that I'm currently working on scaling some Python app. Specifically, now