programming is hard

# I was working on a migration that had a decent chance of messing up my database 
# and wanted assurance it would work with production data, not just my fixtures.

# Building on Bojan Mihelac's code to download files, I wrote a Capistrano task 
# to load the production database into my local database. And then capistrano 
# 1.4.0 was released with a built-in get method for downloading files. So if 
# you have 1.4.0, you can just throw away that whole function.

# Get file remote_path from FIRST server targetted by
# the current task and transfer it to local machine as path, SFTP required
# http://source.mihelac.org/articles/2007/01/11/capistrano-get-method-download-files-from-server
def actor.get(remote_path, path, options = {})
  execute_on_servers(options) do |servers|
    self.sessions[servers.first].sftp.connect do |tsftp|
      logger.info "Get #{remote_path} to #{path}"
      tsftp.get_file remote_path, path
    end
  end
end

desc "Load production data into development database"
task :load_production_data, :roles => :db, :only => { :primary => true } do
  require 'yaml'
 
  database = YAML::load_file('config/database.yml')
 
  filename = "dump.#{Time.now.strftime '%Y-%m-%d_%H:%M:%S'}.sql"
  on_rollback { delete "/tmp/#{filename}" }
 
  run "mysqldump -u #{database['production']['username']} –password=#{database['production']['password']} #{database['production']['database']} > /tmp/#{filename}" do |channel, stream, data|
    puts data
  end
  get "/tmp/#{filename}", filename
  exec "/tmp/#{filename}"
  exec "mysql -u #{database['development']['username']} –password=#{database['development']['password']} #{database['development']['database']} < #{filename}; rm -f #{filename}"
end

# After adding the code to the tail of my config/deploy.rb, I ran cap 
# load_production_data. Then I had a full copy of the production database 
# to tinker with until I was content my migration was flawless.

# Production data is also useful for other things. I can run complicated 
# stats queries without worrying about bogging down the site, and see layout 
# bugs that don't happen unless there's a few dozen tags on the page