Mike Coutermarsh

Using Multi-Node Elasticache with Rails

When using multi-node Elasticache memcached with Rails, it's critically important to get your setup correct. If you don't, your application will connect to memcached nodes at random (!!!). Resulting in low cache hit rates. How to setup Conveniently, there is a gem for this, dalli-elasticache. gem "dalli-elasticache" Using the gem for

Sidekiq connecting logs in test

Sidekiq 7.0.6 connecting to Redis with options If you have these all over your Rails test logs, here is how you can disable them for test. In test/test_helper.rb, add the following: Sidekiq.logger.level = Logger::WARN Now your test logs will be clean. This took

New index name generation in Rails 7.1

For as long as I can remember Rails has had this little quirk where it will auto generate index names that are too long. A couple weeks ago Andrew Culver tweeted out his wish for this to be improved. I'll contribute $500 to the bounty for anyone who is willing

Top 5 Ruby gems for Rails apps

I recently shared a couple of my favorite gems on Twitter. And people asked for more! These are my top 5 must have gems for any Rails app + my reasoning and some tips on how to best use them. 1. Pry 2. Flipper 3. Sidekiq 4. Rack::Attack 5. Prometheus

No fear Rails schema changes

Over on the PlanetScale blog I just wrote up how we handle schema changes in our own Rails app. It's the best workflow I've ever used for Rails migrations. It's both inspired by and better than the custom tooling I had access to when working for GitHub. Click the big

There was an error parsing Gemfile: windows is not a valid platform

I hit this error recently. To fix this, you need to update to a newer version of bundler. gem update bundler Good luck, hope this saved you some time. Error There was an error parsing `Gemfile`: `windows` is not a valid platform.

Trick for fixing Rails `find_by` N+1's

Recently I had some code that was doing 100's of find_by queries. Due to the way it was setup, a simple fix using includes wasn't possible. I was able to know which records would be called via find_by though, meaning I should be able to preload all the

New Rails health check endpoint

Rails just recently added a default /up route that will return a 200 when the application is running. I've had to implement this in pretty much every Rails app I've ever worked on. This is a nice addition! If you're not familiar. This is useful for load balancers which need

Solving N+1’s with Rails `exists?` queries

I recently solved a Rails performance issue with exists? queries in our Rails API. Shared all the details on PlanetScale's blog. Check it out here: Solving N+1's with Rails exists queries.

Searching complex Rails routes

Mastering the routes command will save you a lot of time. Here are a pro tips on how to use it. rails routes Prefix Verb URI Pattern Controller#Action new_user_session GET /sign-in(.:format) users/sessions#new {:subdomain=>"auth"} user_session POST /sign-in(.:format)

Local Dev for a Ghost Theme

I recently customized the default Ghost Casper theme for this blog. It took me a while to figure out a good local development flow. Here is what I ended up with. 1. Install Ghost locally First, you need to be running a Ghost instance locally. Instructions for doing this are

Rails + MySQL: Querying JSON

Here's how to use ActiveRecord to query a JSON column in MySQL. In this example we have a json column user_settings. We want to find which records have theme set with a value. Model.where("JSON_EXTRACT(user_settings, '$.theme') IS NOT NULL").count JSON_EXTRACT is the

PlanetScale

Building a multi-region Rails application with PlanetScale

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PlanetScale

Introducing FastPage: Faster offset pagination for Rails apps

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PlanetScale

Ruby on Rails: 3 tips for deleting data at scale

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PlanetScale

Deploy requests now alert on potential unwanted changes

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PlanetScale

Identifying slow Rails queries with sqlcommenter

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The anxiety of tech debt

No perfect code or system exists. Ask any engineer and they’ll have a list of improvements for most any file they’ve ever touched. This list of negatives can weigh on people. “We need to fix it eventually” or bad things will happen. Like any source of anxiety, the

PlanetScale

How we made PlanetScale's background jobs self-healing

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Using GitHub Package Registry with Netlify

This took me too long to figure out. I hope it helps you. Here’s the best way I’ve found to get GitHub Packages working with a Netlify build. 1. Add this file to your repo. I put it at .npmrc-netlify in the root of the project. This keeps

You should be using a clipboard manager

If you don’t have one already, install one and start using it. * Set a LONG history (mine is 3 months). * Now every code snippet you ever copy is in an easily searchable database so you can pull it back up whenever you need it. I personally use Paste and

PlanetScale

Using entropy for user-friendly strong passwords

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I still use vim

You probably saw this video and are wondering: “After all this time, do you still use vim?”. Yes, I do. And I still love it. My setup also hasn’t changed that much. I still use Vim + iTerm2 for almost all of my work. My dotfiles are still public if

PlanetScale

How our Rails test suite runs in 1 minute on Buildkite

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Why infrastructure engineers prefer MySQL

For years I’ve been noticing this pattern of infrastructure engineers I really respect preferring MySQL and product engineers preferring Postgres. It took quite a while for me to understand it. Especially coming from my background as a product engineer. Different types of engineers value different things Infrastructure engineers generally