module Gitlab # Checks if a set of migrations requires downtime or not. class DowntimeCheck # The constant containing the boolean that indicates if downtime is needed # or not. DOWNTIME_CONST = :DOWNTIME # The constant that specifies the reason for the migration requiring # downtime. DOWNTIME_REASON_CONST = :DOWNTIME_REASON # Checks the given migration paths and returns an Array of # `Gitlab::DowntimeCheck::Message` instances. # # migrations - The migration file paths to check. def check(migrations) migrations.map do |path| require(path) migration_class = class_for_migration_file(path) unless migration_class.const_defined?(DOWNTIME_CONST) raise "The migration in #{path} does not specify if it requires " \ "downtime or not" end if online?(migration_class) Message.new(path) else reason = downtime_reason(migration_class) unless reason raise "The migration in #{path} requires downtime but no reason " \ "was given" end Message.new(path, true, reason) end end end # Checks the given migrations and prints the results to STDOUT/STDERR. # # migrations - The migration file paths to check. def check_and_print(migrations) check(migrations).each do |message| puts message.to_s # rubocop: disable Rails/Output end end # Returns the class for the given migration file path. def class_for_migration_file(path) File.basename(path, File.extname(path)).split('_', 2).last.camelize. constantize end # Returns true if the given migration can be performed without downtime. def online?(migration) migration.const_get(DOWNTIME_CONST) == false end # Returns the downtime reason, or nil if none was defined. def downtime_reason(migration) if migration.const_defined?(DOWNTIME_REASON_CONST) migration.const_get(DOWNTIME_REASON_CONST) else nil end end end end