'Yields AuthProvider instances for the provided configfile that match the
filters.'

def active_authenticators(self, email, username, password):

    try:
        for authenticator in self.authenticators:
            filter_template = authenticator.filter_template
            if filter_template:
                filter_str = filter_template.format(email=email, username=username, password=password)
                passed_filter = eval(filter_str, {'__builtins__': None}, {'str': str})
                if (not passed_filter):
                    continue
            (yield (authenticator.plugin, authenticator.options))
    except Exception:
        log.exception('Active    Authenticators    Failure')
        raise
