def get_updaters(env):
    global updater_instances
    if not updater_instances:
        updater_instances = []
        fqcns = env.get_property(DEFAULT_CONFIG_FILE, PROPERTY_UPDATER_CLASSES)
        if fqcns:
            for fqcn in fqcns:
                env.log("Creating a new updater instance of {}".format(fqcn))
                klass = find_class(fqcn)
                updater = klass(env)
                if updater:
                    updater_instances.append(updater)