Bundler is a great way to control the versions of the gems that are used in your Ruby application, but it requires you to run Ruby scripts and tools (such as rake and heroku) by prefixing them with an extra command (e.g. bundle exec rake). This is a pain, can be easy to forget, and can cause no end of subtle bugs if the script that you're running can be found outside of the bundled application, in your shell's PATH.

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If, like me, you've recently discovered the wonderful speed of the ack search tool, you may be frustrated to find that it ignores some of your source code. Files that you know should be appearing in your search results just don't show up, as ack doesn't consider .haml or .scss files to be worth searching. Well, we can fix that.

Configure your ack...

A user recently reported poor performance on one of our Rails apps. I pulled up New Relic's performance graphs and checked what was happening around the time that we received the email. Sure enough there was a massive spike over a 10 minute period in the time taken to serve a request.

Analyse Rails log files with cut, sort and uniq

The biggest news in Rails 2.3 is its support for Rack, the WSGI inspired Ruby web server interface. Of all the Rack goodness that has come along lately, the one that has me the most excited is Bryan Helmkamp's Rack::Test library, of which Bryan said "Basically, I extracted Merb’s request helper code into a small, reusable, framework agnostic library."

Read more: Using Rack::Test with Rails

Many web sites are built using a variety of web applications, using different web frameworks. These sub sites share the same branding and ought to re-use the same CSS and images. How do you re-use these files within your Rails application, without the maintenance overhead of copying and pasting the code into each new application?

Find out how to share CSS between applications

The images, CSS and JavaScript files served up by your Rails application can usually be cached by the web browser, rather than being downloaded every time the browser loads a page on your site. Rails gives you some help here, but it doesn't happen automatically -- you need to configure your web server to set the HTTP Expires header.

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It's generally acknowledged to be good practice to keep your production database.yml file away from your version control system. Why? So that people snooping around your version control system don't find your database password. There are plenty of examples out there that tell you how to set your production password with Capistrano, but I'm talking about the database.yml file used during development.

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I've been trying to persuade git-svn to work properly with Rails plugins that are installed via svn:externals. Whilst working out how to do it I stumbled across several great articles, but I couldn't get any of the solutions presented to work perfectly.

After a bit of head scratching I got it sorted, and wrapped the process up in a little utility called git-me-up.

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God is a very neat piece of software, frequently used by Rails developers to monitor mongrel servers, and restart them if/when they crash or use up too many system resources.

Its use isn't limited purely to monitoring web servers though; you can monitor pretty much anything you like. Read on to see how to configure it to monitor the Ruby job processing daemon, BackgrounDRb.

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