• Managing Versions With asdf

    Three years ago, I switched my ruby version manager from rvm to rbenv. Since then, I’ve been using rbenv without complaint. It just works. I now find myself working on more complex projects, that needs specific version of Ruby, Elixir, Postgres, Terraform and others.

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  • The REPL: Issue 50 - September 2018

    How to teach yourself hard things

    Julia Evans writes a great article on how to learn… to learn. In her traditional straight-forward fashion, she describes the method she has used to learn things that are difficult. She breaks the process down into approachable skills that anyone can learn (e.g ask questions, have confidence in your knowledge). I also recommend following her on twitter. She posts comics often about unix tools: I always learn something knew from them.

    Distributed Agreement on Random Order – Fun with Lamport Timestamps

    If you’ve ever done some digging into distributed computing, you will have heard of Lamport Clocks. In this post, Quentin Duval, details step by step on how to construct an application that uses Lamport’s algorithm for reaching agreement on the order of events across a distributed system.

    Upgrading GitHub from Rails 3.2 to 5.2

    Working as a Rails developer, I’ve found myself a few times in the same situation GitHub was: Relying on an old version of a framework that has now become a liability, and upgrading is anything but straight forward. In this post, Eileen Uchitelle describes the strategy that GitHub used to upgrade. I especially like the section about lessons learned: It’s one of my favorite things about the software community. The willingness to share with others allows us to learn from each other. Thanks Eileen!

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  • The REPL: Issue 49 - August 2018

    Cost of a Join

    Brian Davis writes a detailed post of how expensive it is to do join queries in postgres. The details are very interesting, as is the conclusion: Join operations are usually cheap.

    Elixir: a few things about GenStage I wish I knew some time ago

    I’ve recently started working on an Elixir project that seems perfectly suited to use GenStage. In this article Andrei Chernykh complements the GenStage documentation and explains how to use it in an approachable manner.

    What they don’t tell you about event sourcing

    Hugo Rocha writes about the pitfalls of using event sourcing. Like most engineering techniques, it is not a perfect fit for every situation. In fact, I believe event sourcing is a sufficiently different paradigm to traditional CRUD applications that it makes it difficult to approach in a iterative manner that other techniques can be incorporated into existing systems.

    Why JWTs Suck as Session Tokens

    Randall Degges writes a good primer on what JWT tokens are, what security guarantees they give, and what problem they are a good solution for. Namely, using them in distributed systems to reduce inter-service calls to verify authentication (or other claims). As the title not-so-subtly suggests, they are not great as session tokens. Most web frameworks already have this problem solved. There is no need to re-invent wheels that are rolling just fine.

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  • On Taking Notes

    For over a year now, I’ve started taking methodical notes as I go about my daily work as a Software Engineer. I find the process worthwhile.

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  • The REPL: Issue 48 - July 2018

    Web Architecture 101

    The world-wide web is built on top of many abstractions. That is what makes it powerful. As a user, we are typically just concerned with a browser and a “site”. When I first started programming for the web, I learned about HTTP, request and responses. Sometimes, one needs to dig deeper into common architecture patterns. In this article, Jonathan Fulton covers some of that architecture: DNS, load balancers, web and application servers, databases, caching. I found it to be a very useful reference. Note: As is always the case with computers, there are more levels of abstraction to learn: TCP, IP, UDP, TLS, etc.

    Scaling the GitLab database

    Yorick Peterse discusses some of the scaling issues that GitLab went through and how they resolved them. I find these type of articles very enlightening. Both for the solution they chose and for those that they discarded: Your particular scaling problem might look different, making one of those solutions more attractive.

    Queries on Rails - Showcasing Active Record and Arel

    Pedro Rolo discusses how to go beyond basic queries with ActiveRecord and Arel. I personally use techniques similar to the ones outlined in the article often. Caution: Arel is considered private API by Rails maintainers. If you decide to use it, there might be some work needed to ensure your code works when upgrading Rails. I’ve never had a significant problem with that, provided that I have good tests around complex queries. I much prefer Arel to using long and complicated sql fragments as strings. I believe those are even more brittle.

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