A Minimum Viable CloudFormation Template
Sometimes when testing CloudFormation features I need a minimum viable template to try that feature with.
Sometimes when testing CloudFormation features I need a minimum viable template to try that feature with.
On several Django projects I’ve worked on, there has been a requirement for performing database modifications beyond Django migrations. For example:
In my blog post and DjangoCon Europe talk earlier this year How to Score A+ for Security Headers on Your Django Website, I covered that Feature-Policy was a “bonus header”. In a recent update, Scott Helme wrote that an A+ on SecurityHeaders.com now requires Feature-Policy. Also it no longer requires X-Xss-Protection (though it’s still a good idea).
I’ve been working with CloudFormation in some form for about five years now. Two years ago at Time Out, I helped write an in-house tool that performed some basic template linting. One year ago at Genus AI, I started using the AWS Labs tool cfn-lint to validate my templates before deployment. It’s really neat, covers a lot more than our in-house tool did, and has saved me from a number of mistakes.
This is a story about how I sped up a client’s Django test suite to be three times faster, through swapping the test case class in use.
One thing I often ask for in code review is conversion of tuples to lists. For example, imagine we had this Django admin class:
Every time I pick up the Python job queue Celery after not using it for a while, I find I’ve forgotten exactly how RabbitMQ works. I find the Advanced Message Queuing Protocol (AMQP) concepts drop out of my head pretty quickly: Exchanges, Routing Keys, Bindings, Queues, Virtual Hosts…
If the title worried you about my mental state, you can relax. It’s about the Python code formatter Black!
PyLondinium ran for the second time last weekend. It’s a three day conference from Friday to Sunday, held in central London at the Bloomberg office.
CloudFormation’s stack drift detection feature is useful. It discovers ways your infrastructure that you beautifully set up with Infrastructure-as-Code has been fiddled with manually. Often this results from a “quick temporary fix” being applied manually on the web console at 2am, then forgotten about.
My library apig-wsgi bridges between AWS API Gateway’s JSON format for HTTP requests and Python WSGI applications. Recently Théophile Chevalier opened an issue requesting the library add an extra WSGI environ variable. I closed it by pointing out that it’s not much code to add a custom WSGI middleware to do so (plus the exact key is a bit out of scope for the library).
I discovered GIFCities recently. It’s a project by the Internet Archive for browsing GIFs extracted from their Geocities archive.
I received a cheery notification email (twice) from AWS that they’re deprecating Ubuntu 14.04 on CodeBuild:
DjangoCon Europe 2019 was great fun. I loved meeting old and new friends, giving my talk and workshop, and learning in the other talks.
I found Mikey Ariel’s talk on documentation at DjangoCon Europe 2019 “Docs or It Didn’t Happen” well timed. I’ve recently been focussing on the lifelong skill of writing, in particular for technical writing such as this blog.
Code coverage is a simple tool for checking which lines of your application code are run by your test suite. 100% coverage is a laudable goal, as it means every line is run at least once.
A discussion recently came up on django-developers mailing list about how to build the SQL query CREATE TABLE ... AS SELECT (CTAS) with Django’s ORM. This statement and its cousin INSERT ... SELECT are useful for re-shaping data inside your database, using SELECT queries.
This is a recipe I’ve used on a number of projects. It combines pytest fixtures with Botocore’s Stubber for an easy testing experience of code using Boto3. (Botocore is the library behind Boto3.)
I occasionally enjoy solving algorithmic problems, for example Project Euler or The Advent of Code. I’ve been doing them since I was a pimply PHP-slinging teenager, competing with my peers across the UK in the British Informatics Olympiad. It was terribly nerdy and terribly fun.
On Saturday, I posted my guide on Scoring A+ for Security Headers in Django, following my talk at DjangoCon Europe. I thought it would be a good idea to step up and make my own site score A+, rather than a dismal F! My site isn’t built in Django, but as a Jekyll static site. It’s hosted on AWS S3 and CloudFront.
On Thursday I gave a workshop at DjangoCon Europe on deploying a Django application on AWS Lambda. I gave participants a Git repository to clone and temporary AWS keys to individual, restricted IAM users on my Workshops AWS account.
This is a blog post version of the talk I gave at DjangoCon Europe 2019 on the 10th April.
A lot of people pick Flask over Django because they believe it is simpler to start with. Indeed, the Flask front page includes an 8 line “hello world” application, while the Django default project has 172 lines in 5 files, and still doesn’t say “hello world”! (It does show you a welcome rocket and have a full admin interface though, both are pretty fun).
I was at PyCon Namibia in Windhoek from the 19th to 21st of February, and had an amazing time! PyCon Namibia is one of the longest running PyCons in Africa, this being its fifth edition in as many years.
I quite often get asked for resources on where to learn Django. Here’s a list of the places I know!
