Cache your clean test DB for blazingly fast test environment setup

db_cached.rake

# this rakefile is designed to be run alone. rails needs to be explicitly loaded if needed

require 'digest/sha1'
require 'fileutils'
require 'yaml'

namespace :db do
  namespace :cached do
    desc 'load the cached dump or regenerate if necessary'
    task :setup_all do
      rails_root = File.expand_path('../../..', __FILE__)
      def rails_root.join(*paths)
        File.join(self, *paths)
      end

      master_hash = lambda do
        seed_path = rails_root.join('db', 'seed')
        hash_paths = Dir.glob(File.join(seed_path, '*.{yml,csv}')).sort
        hash_paths << rails_root.join('db', 'schema.rb')
        hash_paths.reduce('') { |m, p| Digest::SHA1.hexdigest(m + File.read(p)) }
      end

      schema_migrated_to = File.open(rails_root.join('db', 'schema.rb')) do |f|
        f.detect { |l| l =~ /:version => (\d+)/ }
        $1.to_i
      end
      newest_migration = Dir.entries(rails_root.join('db', 'migrate')).sort.last.split('_').first.to_i #sup demeter
      needs_migration = newest_migration > schema_migrated_to

      FileUtils.mkdir_p(rails_root.join('db', 'cached'))
      sql_dump_path = lambda { rails_root.join('db', 'cached', "all-#{master_hash.call}.sql") }
      db_config = YAML.load_file(rails_root.join('config', 'database.yml'))['test']
      password_string = db_config['password'] ? "-p#{db_config['password']} " : ""

      current_sql_dump_path = sql_dump_path.call
      if File.exists?(current_sql_dump_path) && !needs_migration
        puts "Cached dump found, loading via SQL"
        `mysqladmin -u#{db_config['username']} #{password_string}-f drop #{db_config['database']}`
        `mysqladmin -u#{db_config['username']} #{password_string}create #{db_config['database']}`
        `mysql -u#{db_config['username']} #{password_string}#{db_config['database']} < #{current_sql_dump_path}`
      else
        puts "No cached dump found or schema needs migration, loading all from scratch"
        load rails_root.join('Rakefile') unless defined? Rails
        Rake::Task['cruise:db_setup'].invoke
        `mysqldump -u#{db_config['username']} #{password_string}#{db_config['database']} > #{sql_dump_path.call}`
      end
    end

    desc 'delete caches not used for the given amount of days (default=7)'
    task :clean, :age do |t, args|
      args.with_defaults(:age => 7)
      puts "Deleting DB caches not used in #{args.age} days"

      db_cached_dir = File.expand_path('../../../db/cached', __FILE__)
      files_deleted = 0

      Dir.entries(db_cached_dir).each do |path|
        next if path[0] == '.'
        full_path = File.join(db_cached_dir, path)

        if Time.now - File.atime(full_path) > 86400 * args.age.to_i
          File.delete(full_path)
          files_deleted += 1
        end
      end

      puts "Deleted #{files_deleted} DB caches"
    end
  end
end

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