Contents

require 'percona_migrator'
require 'lhm' # It's our own Lhm adapter, not the gem
require 'rails'

module PerconaMigrator
  class Railtie < Rails::Railtie
    railtie_name :percona_migrator

    # It drops all previous database connections and reconnects using this
    # PerconaAdapter. By doing this, all later ActiveRecord methods called in
    # the migration will use this adapter instead of Mysql2Adapter.
    #
    # It also patches ActiveRecord's #migrate method so that it patches LHM
    # first. This will make migrations written with LHM to go through the
    # regular Rails Migration DSL.
    initializer 'percona_migrator.configure_rails_initialization' do
      ActiveSupport.on_load(:active_record) do

        ActiveRecord::Migration.class_eval do
          alias_method :original_migrate, :migrate

          # Replaces the current connection adapter with the PerconaAdapter and
          # patches LHM, then it continues with the regular migration process.
          #
          # @param direction [Symbol] :up or :down
          def migrate(direction)
            reconnect_with_percona
            include_foreigner if defined?(Foreigner)

            ::Lhm.migration = self
            original_migrate(direction)
          end

          # Includes the Foreigner's Mysql2Adapter implemention in
          # PerconaMigratorAdapter to support foreign keys
          def include_foreigner
            Foreigner::Adapter.safe_include(
              :PerconaMigratorAdapter,
              Foreigner::ConnectionAdapters::Mysql2Adapter
            )
          end

          # Make all connections in the connection pool to use PerconaAdapter
          # instead of the current adapter.
          def reconnect_with_percona
            connection_config = ActiveRecord::Base.connection_config
            ActiveRecord::Base.establish_connection(
              connection_config.merge(adapter: 'percona')
            )
          end
        end
      end
    end
  end
end

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
percona_migrator-0.1.0.rc.7	lib/percona_migrator/railtie.rb
percona_migrator-0.1.0.rc.6	lib/percona_migrator/railtie.rb