538 items tagged “django”
Django Chat: Datasette, LLMs, and Django. I’m the guest on the latest episode of the Django Chat podcast. We talked about Datasette, LLMs, the New York Times OpenAI lawsuit, the Python Software Foundation and all sorts of other topics. # 24th January 2024, 8:41 pm
DSF calls for applicants for a Django Fellow. The Django Software Foundation employs contractors to manage code reviews and releases, responsibly handle security issues, coach new contributors, triage tickets and more.
This is the Django Fellows program, which is now ten years old and has proven enormously impactful.
Database generated columns: GeoDjango & PostGIS. Paolo Melchiorre advocated for the inclusion of generated columns, one of the biggest features in Django 5.0. Here he provides a detailed tutorial showing how they can be used with PostGIS to create database tables that offer columns such as geohash that are automatically calculated from other columns in the table. # 11th December 2023, 7:14 pm
Database Migrations. Vadim Kravcenko provides a useful, in-depth description of the less obvious challenges of applying database migrations successfully. Vadim uses and likes Django’s migrations (as do I) but notes that running them at scale still involves a number of thorny challenges.
The biggest of these, which I’ve encountered myself multiple times, is that if you want truly zero downtime deploys you can’t guarantee that your schema migrations will be deployed at the exact same instant as changes you make to your application code.
This means all migrations need to be forward-compatible: you need to apply a schema change in a way that your existing code will continue to work error-free, then ship the related code change as a separate operation.
Vadim describes what this looks like in detail for a number of common operations: adding a field, removing a field and changing a field that has associated business logic implications. He also discusses the importance of knowing when to deploy a dual-write strategy. # 1st October 2023, 11:55 pm
Building Search DSLs with Django (via) Neat tutorial by Dan Lamanna: how to build a GitHub-style search feature—supporting modifiers like “is:open author:danlamanna”—using PyParsing and the Django ORM. # 19th June 2023, 8:30 am
Writing a chat application in Django 4.2 using async StreamingHttpResponse, Server-Sent Events and PostgreSQL LISTEN/NOTIFY (via) Excellent tutorial by Víðir Valberg Guðmundsson on implementing chat with server-sent events using the newly async-capable StreamingHttpResponse from Django 4.2x.
He uses PostgreSQL’a LISTEN/NOTIFY mechanism which can be used asynchronously in psycopg3—at the cost of a separate connection per user of the chat.
The article also covers how to use the Last-Event-ID header to implement reconnections in server-sent events, transmitting any events that may have been missed during the time that the connection was dropped. # 19th May 2023, 3:42 pm
Django 4.2 released. “This version has been designated as a long-term support (LTS) release, which means that security and data loss fixes will be applied for at least the next three years.” Some neat new async features, including improvements to async streaming responses. # 3rd April 2023, 2:14 pm
djngo.com: Portable Django (via) “A 20mb executable zip file with Python 3.6 and Django 2.2. Works on Windows, Linux, MacOSX with x86_64 and aarch64 (yes, Apple M1 and Raspberry Pi).” The latest wizardry from the ecosystem surrounding the Cosmopolitan project, which provides a should-be-impossible mechanism for running the same executable on a bunch of different platforms. This utility by Ariel Núñez bundles Python and Django and SQLite, such that a Django application can become a portable executable ready to run on multiple platforms. It’s currently limited to Python 3.6 and Django 2.2 since those are the versions that run under Cosmopolitan, but I expect we’ll see more recent versions of those dependencies in the future. # 24th February 2023, 12:52 am
How to simulate a broken database connection for testing in Django (via) Neil Kakkar explores the options using unittest.patch() and then settles on a neater pattern using “with connection.execute_wrapper(QueryTimeoutWrapper()):” to simulate the exact exception he needs to test against. # 15th January 2023, 8:31 pm
I spent most of this week at DjangoCon in San Diego—my first outside-of-the-Bay-Area conference since the before-times.[... 1184 words]
How to implement a “dry run mode” for data imports in Django (via) Adam Johnson describes in detail a beautiful pattern for implementing a dry-run mode for a Django management command, by executing ORM calls inside an atomic() transaction block, showing a summary of changes that are made and then rolling the transaction back at the end. # 13th October 2022, 4:22 pm
Black 22.1.0 (via) Black, the uncompromising code formatter for Python, has had its first stable non-beta release after almost four years of releases. I adopted Black a few years ago for all of my projects and I wouldn’t release Python code without it now—the productivity boost I get from not spending even a second thinking about code formatting and indentation is huge.
How to Add a Favicon to Your Django Site (via) Adam Johnson did the research on the best way to handle favicons—Safari still doesn’t handle SVG icons so the best solution today is a PNG served from the /favicon.ico path. This article inspired me to finally add a proper favicon to Datasette. # 20th January 2022, 7:03 am
Earlier this week I released Django SQL Dashboard 1.0. I also just released 1.0.1, with a bug fix for PostgreSQL 10 contributed by Ryan Cheley.[... 629 words]
Django SQL Dashboard 1.0 (via) As part of my ongoing attempt to be braver about 1.0 releases (crucial if you want to do semantic versioning properly) I’ve released version 1.0 of Django SQL Dashboard, my Datasette-inspired app for Django that adds an interface for running read-only, bookmarkable SQL queries against a PostgreSQL database. The new version adds a column cog menu providing shortcuts for changing the sort order, counting distinct values and performing a group-by/count against column values. # 1st July 2021, 5:44 pm
Django for Startup Founders: A better software architecture for SaaS startups and consumer apps (via) The opening section of this article has very little to do with Django: it’s an insightful description of the technical challenges faced by a startup that is still seeking product-market fit. Alex then extends that into his own architectural recommendations for startups building with Django to help waste as little time as possible on problems that aren’t core to the product they are building. # 24th June 2021, 8:43 pm
HackSoft Django styleguide: services and selectors. HackSoft’s Django styleguide uses the terms “services” and “selectors”. Services are functions that live in services.py and perform business logic operations such as creating new entities that might span multiple Django models. Selectors live in selectors.py and perform more complex database read operations, such as returning objects in a way that respects visibility permissions. # 24th May 2021, 7:17 pm
I’ve released the first non-alpha version of Django SQL Dashboard, which provides an interface for running arbitrary read-only SQL queries directly against a PostgreSQL database, protected by the Django authentication scheme. It can also be used to create saved dashboards that can be published or shared internally.[... 2171 words]
Work on VIAL for Vaccinate The States continues.[... 1503 words]
Weeknotes: Vaccinate The States, and how I learned that returning dozens of MB of JSON works just fine these days
On Friday VaccinateCA grew in scope, a lot: we launched a new website called Vaccinate The States. Patrick McKenzie wrote more about the project here—the short version is that we’re building the most comprehensive possible dataset of vaccine availability in the USA, using a combination of data collation, online research and continuing to make a huge number of phone calls.[... 1109 words]
As I mentioned back in February, I’ve been working with the VaccinateCA project to try to bring the pandemic to an end a little earlier by helping gather as accurate a model as possible of where the Covid vaccine is available in California and how people can get it.[... 2157 words]
A few small releases this week, for
This week I started a limited production run of my new backend for Vaccinate CA calling, built a
tableau-to-sqlite import tool and started working on a subset of Datasette for PostgreSQL and Django called
My ambitious goal for the day was to get the new Django/PostgreSQL preview into a state where we could start sending example API requests to it from the
This week I got involved with the VaccinateCA effort. We are trying to end the pandemic a little earlier, by building the most accurate database possible of vaccination locations and availability in California.[... 1154 words]
My progress slowed a bit today as I started digging into some things I’m less familiar with—but I’ve found some tricks that I think will help us out a lot.[... 1089 words]
I made a bunch of progress on the Django backend prototype-that-soon-won’t-be-a-prototype today.[... 935 words]
My goal by the end of this week is to have a working proof of concept for a Django + PostgreSQL app that can replace Airtable as the principle backend for the https://www.vaccinateca.com/ site. This proof of concept will allow us to make a go or no-go decision and figure out what else needs to be implemented before we can start using it to track calls.[... 762 words]
The trouble with transaction.atomic (via) David Seddon provides a detailed explanation of Django’s nestable transaction.atomic() context manager and describes a gotcha that can occur if you lose track of whether your code is already running in a transaction block, since you may be working with savepoints instead—along with some smart workarounds. # 20th November 2020, 3:57 pm