leaf_predicate.py 文件源码

def ast(self):
        """Create Python AST of this predicate.

        :return: AST representation of predicate
        """
        # we could directly use db[task] in predicates, but predicates should not handle database errors,
        # so leave them on higher level (selinon) and index database before predicate is being called

        kwargs = []
        # we want to avoid querying to database if possible, if a predicate does not require message, do not ask for it
        if self.requires_message():
            # this can raise an exception if check was not run, since we are accessing storage that can be None
            kwargs.append(ast.keyword(arg='message',
                                      value=ast.Call(func=ast.Attribute(value=ast.Name(id='db', ctx=ast.Load()),
                                                                        attr='get', ctx=ast.Load()),
                                                     args=[ast.Str(s=self._task_str_name())],
                                                     keywords=[], starargs=None, kwargs=None)))
        if self.requires_node_args():
            kwargs.append(ast.keyword(arg='node_args', value=ast.Name(id='node_args', ctx=ast.Load())))

        kwargs.extend([ast.keyword(arg=k, value=ast.Str(s=v)) for k, v in self._args.items()])

        return ast.Call(func=ast.Name(id=self._func.__name__, ctx=ast.Load()),
                        args=[], starargs=None, kwargs=None, keywords=kwargs)