Method: MongoMapper::Migrator#migrate

Defined in:
lib/mongo_mapper/migrator.rb

#migrate ⇒ Object 



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# File 'lib/mongo_mapper/migrator.rb', line 69

def migrate
  current = migrations.detect { |m| m.version == current_version }
  target = migrations.detect { |m| m.version == @target_version }

  if target.nil? && !@target_version.nil? && @target_version > 0
    raise UnknownMigrationVersionError.new(@target_version)
  end
  
  start = up? ? 0 : (migrations.index(current) || 0)
  finish = migrations.index(target) || migrations.size - 1
  runnable = migrations[start..finish]
  
  # skip the last migration if we're headed down, but not ALL the way down
  runnable.pop if down? && !target.nil?
  
  runnable.each do |migration|
    # On our way up, we skip migrating the ones we've already migrated
    next if up? && migrated.include?(migration.version.to_i)

    # On our way down, we skip reverting the ones we've never migrated
    if down? && !migrated.include?(migration.version.to_i)
      migration.announce 'never migrated, skipping'; migration.write
      next
    end

    migration.migrate(@direction)
    record_version_state_after_migrating(migration.version)
  end
end