Category: Rails

Something I frequently need to do when deploying a Rails application is determine the current migration version of a database. In the past, I’ve done this by bringing up mySQL and typing:

SELECT version FROM schema_info

Well, I’m finally tired of doing that so I cooked up this Rake task:

namespace :db do
  desc "Print current database migration version to the console"
  task :version => :environment do
    puts "VERSION=#{ActiveRecord::Migrator.current_version}"
  end
end

To install, copy and paste into lib/tasks/common.rake (or wherever you store your custom Rake tasks). Then fire up a terminal window and feel the power:

$ rake db:version
(in /Users/matt/project)
VERSION=125

I’m surprised this isn’t already in Rails. Sure, there’s script/about, but I always forget to use it. It also spits out other information I don’t typically need to know.

Why care about the migration version in the first place? When you’re on a project with multiple Rails deployments (dev/test/prod) and multiple developers creating migrations in multiple branches, it comes in quite handy.

Mike Clark made a recent post on his blog about how to handle Rails versions with Capistrano. Very nice stuff. I’ve put his code samples to immediate use with an app I’m preparing to convert to Rails 1.2.1.

I’ve run into some trouble this week, though, as I want to update one of my client projects that still runs version 1.1.6 of Rails. Mike’s Capistrano task takes a revision number so checking out a fresh copy with his script looks something like this.

rake deploy_edge REVISION=5990 RAILS_PATH=/path/to/shared/rails

This checks out 1.2.1 into the specified directory. After spending a few minutes trying to find the revision number for 1.1.6 (and chatting briefly with my Campfire peeps about the best way to proceed) I’ve decided that it’s safer to use tags instead of revisions. Deploys now look like this:

rake deploy_edge TAG=rel_1-1-6 RAILS_PATH=/path/to/shared/rails

Much more readable. The only downside, of course, is losing revision granularity. I’m essentially tied to the whim of the Core team as to when they decide to create new tags. But on the other hand, most of my projects aren’t currently running on Edge so this is suitable for my needs at the moment.

I’ve included my rewrite of the task below. Just drop it in common.rake or wherever you prefer to put your custom tasks. Reading Mike’s post would be a good idea too since he explains how to get this working with a remotely deployed Rails application.

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Ever notice the cruft you get when running Rails tests from the command line? It’s horrible, especially if your project has more than a dozen test files:

/opt/local/bin/ruby -Ilib:test "/opt/local/lib/ruby/gems/1.8/gems/rake-0.7.1/lib/rake/rake_test_loader.rb"
"test/unit/activity_test.rb" "test/unit/address_test.rb" "test/unit/application_helper_test.rb"
"test/unit/course_calculations_test.rb" "test/unit/course_test.rb" "test/unit/course_type_test.rb"
"test/unit/credit_hour_test.rb" "test/unit/email_test.rb" "test/unit/exam_test.rb" "test/unit/gender_test.rb"
"test/unit/grade_test.rb" "test/unit/level_test.rb" "test/unit/notifier_test.rb" "test/unit/numeric_test.rb"
"test/unit/obfuscator_test.rb" "test/unit/order_test.rb" "test/unit/school_test.rb" "test/unit/string_test.rb"
"test/unit/student_test.rb" "test/unit/transcript_test.rb" "test/unit/user_test.rb" 
Loaded suite /opt/local/lib/ruby/gems/1.8/gems/rake-0.7.1/lib/rake/rake_test_loader
Started
..................................................................
Finished in 2.509903 seconds.

66 tests, 140 assertions, 0 failures, 0 errors

M@ McCray recently posted a hack to the Terralien Campfire that gives you a nice, clean summary instead:

Loaded suite /opt/local/lib/ruby/gems/1.8/gems/rake-0.7.1/lib/rake/rake_test_loader
Started
..................................................................
Finished in 2.855885 seconds.

66 tests, 140 assertions, 0 failures, 0 errors

Want to start enjoying this super slim summary yourself? Just stick this code in your project’s Rakefile right before the require 'tasks/rails' bit:

Rake::TestTask.class_eval do
  alias_method :crufty_define, :define
  def define
    @verbose = false
    crufty_define
  end
end

Much better! We’re both surprised something like this isn’t already available in Core.