When debugging software, particularly if it's code you didn't write and aren't familiar with, one of the hardest parts can be just determining where to start. Without the right context, you can end up chasing red herrings all over before finally tracking down the underlying problem. Well-placed log messages can help provide that context, saving that time and frustration. In this post, we'll look at adapting a logging technique employed by many Node tools on the command line for use in an Ember.js app in the browser.
Salsify is a multi-tenant SaaS product information exchange platform hosted in Heroku. We utilize delayed job extensively for long running tasks like import/export/search indexing/etc. One of the features we've grown to love about delayed job is its extensibility via plugins (see our other posts). Recently, an increasing number of job workers have been exceeding their dyno memory quota**, and consequently suffering serious performance degradation. While we are always working to improve our code performance, we thought it would be nice to have a mechanism for euthanizing workers that are unrecoverably exhausted. Enter the DelayedJob::YouthInAsiaPlugin.
Over the past few months at Salsify we've spent some time exploring Ember.js and incorporating it into parts of our front-end. There's a lot to say on the topic, but today we'll just be taking a look at one of our first forays outside of the land of Ember's baked-in pieces: automatically generating breadcrumbs based on a user's application state.
Most Rails developers quickly learn that minimizing the number of database queries by properly specifying eager loads is critical for good application performance. Unfortunately specifying eager loads is error prone and can cause encapsulation problems. In this post we'll explore having Rails automatically handle eager loads.
At Salsify we write lots of Capybara integration tests of our single-page app. These tests are a key part of the infrastructure that allow us to move fast and refactor without break anything. Unfortunately as we added more and more tests we started experiencing sporadic hangs and database deadlocks while tearing down tests. After some investigation we figured out the problem was our JavaScript client making AJAX requests to our Rails server during the test teardown process. This post details our journey to stamp out these problems and get our tests running reliably again.
I wanted to share a bit of information that we found interesting when writing active record migrations on tables leveraging STI (Single Table Inheritance). We came across a not so obvious gotcha with STI models re-defined in migration classes and wanted to explore our thought process while solving the subsequent problems.
Previously we blogged about eager loading calculations with database views in Rails to avoid running lots of database queries. The approach we described really only works if your SQL is fairly static and you don't mind creating database views for each of your calculations. In this post we'll explore an alternative approach that avoids these issues by not using database views. First let's quickly recap the problem...
Update: The plugin discussed in this post has been packaged into the delayed_job_heartbeat_plugin gem.
Previously we've blogged about how to write Delayed Job plugins and how to aggregate jobs into job groups. In this post we'll explore how to proactively detect failed Delayed Job workers so their jobs can be retried in a timely manner. This is useful if a worker crashes, is automatically restarted by your platform provider, or is shutdown by auto-scaling infrastructure.
For newcomers to JavaScript, the language's prototypical inheritance model is often a source of confusion, particularly for those used to classical inheritance in languages like Java, C++, and Ruby. Right off the bat, new JS developers generally hit a few blocking questions: