A Quick Guide to Building a Custom Docker Image for CI

Most of today’s popular CI services support running jobs in arbitrary Docker containers. In this post, I’ll describe why Docker is such a great fit for CI and how it can be made even better with custom images.

LocalStack + Terraform + CircleCI for Lambda without AWS

On my current project, we’re using LocalStack in lieu of AWS for development and test. In this post, I’ll walk through how we’ve set it up and what we can do with it.

Android Emulator on CircleCI’s MacOS Executor

The Android Emulator, unfortunately, doesn’t work in CircleCI’s conventional (Docker-based) Android build environment. With a little tinkering, though, we can make it work in another environment!

Sharing TypeScript Code Between Web and React Native

We’re building a hybrid mobile app out of an existing web app. The front end will run out of a webview, and we’re adapting the back end to run on-device in [React Native]. One of the challenges we encountered was how to share code between our existing [monorepo] built with [webpack] and our new React […]

Ergonomic TypeScript Generics with Higher-Order Functions

Much of TypeScript’s flexibility comes from its support for generics. They’re great for building up reusable abstractions so that you can share the “how” across your codebase even as the “what” varies significantly. In this post, I’ll describe a limitation that recently got in my way, and how I worked around it.

Document Your Project’s package.json File

The package.json file is the heart of any Node.js project, but it often goes entirely undocumented. In this post, I’ll review a few areas that are worth documenting, and how I like to do it.

Organize One-Off Task Files with Dated Work Directories

Say you’re about to begin a task that will involve working with some files. Perhaps you’re creating a diagram or encoding some GIFs. Where do you put the files?

Replacing Heroku Review Apps on Non-GitHub Projects

If your software team develops multiple new features simultaneously, you need to be able to deploy and test them in isolation. The gold standard for this is to use Heroku’s review apps, which are temporary environments automatically spun up for each pull request. Unfortunately, the feature only works with GitHub; if you’re using another source […]

Collection Operations on Lazy Sequences in TypeScript with itiriri

I’m currently working in TypeScript after spending a lot of time in F#, and I’ve been experimenting with adapting my favored functional approaches to the former.

Getting Started with AWS Lambda in F#

I recently set out to create my first AWS Lambda function. Of the supported languages, I chose my favorite: F#. In this post, I’ll walk through the process of building a Lambda function in F# and deploying it to AWS. AWS Alphabet Soup Many of Amazon’s web services have famously inscrutable names. After fumbling my […]

Atomic Spin

Atomic Object’s blog on everything we find fascinating.

By: John Ruble

Author: John Ruble