A Rails migration is a tool for changing an application’s database schema. Instead of managing SQL scripts, you define database changes in a domain-specific language (DSL). The code is database-independent, so you can easily move your app to a new platform. You can roll migrations back, and manage them alongside your application source code.
If you’re running a production application, you need metrics. There are great products out there that allow you to gain visibility into how your application is performing, give some nice graphs, and charge you for it. In the Rails community, this is commonly achieved by using NewRelic and Skylight. But for some of us, we achieve visibility by using Prometheus and Grafana that we build and host ourselves.
No matter how carefully coded, reviewed, and tested your Ruby code is, odds are good that at some point you’ll cause a catastrophic failure to at least one system you’re responsible for. How do you prepare yourself? You need a Ruby debugger. In this post, I’ll cover the whole Ruby debugger process—from finding the issue to determining the root cause. Use these instructions for debugging a single Ruby file, a Rails app, or a gem.
Most Rails developers should be pretty familiar with this work flow: open up a controller file in your editor, write some Ruby code inside an action method, visit that URL from the browser and the code you just wrote comes alive. But have you thought about how any of this works? How did typing a URL into your browser's address bar turn into a method call on your controllers? Who actually calls your methods?
Docker Compose is a great tool to develop your Ruby on Rails application locally. It allows you to easily isolate your ruby environment, database, and even Redis if you use something like Sidekiq.
Sending performance metrics from your Ruby app to APM Server can be as easy as installing the elastic-apm Rubygem. Most integrations are plug-n-play, and Rails and Rack support is built in. However there are several ways to add more information to the data as well as ways to set up your own custom instrumentations.
When developing new applications, it’s typical to run into a variety of competitors with similar goals. This is one reason why it is not enough to create an application without ways to monitor and manage it. In fact, usually market leaders emerge rather quickly. So who are these market leaders?
To keep the memory footprint of our Elastic APM agents small, the agents stream events as they happen via long-running POST requests to APM Server The server accepts ndjson which is JSON objects separated with newline \n characters. Can’t get simpler than that.
Logging provides critical value to applications with insight to usage, stats, and metrics, and saves us when debugging a problem. But we often leave logging to poorly implemented afterthoughts. So what should we know to get the most out of our logging? We will look at the Rails logger and some logging best practices.
Troubleshooting is a critical skill for developers and DevOps. As our software grows more sophisticated, our problems do too. The cloud adds a new layer of complexity since we need to know how to find a problem that doesn’t occur locally, but has cropped up on a remote system.
