Python Tornado - 禁用日志记录到 stderr

Question

我有一个简约的 Tornado 应用程序:

import tornado.ioloop
import tornado.web

class PingHandler(tornado.web.RequestHandler):
    def get(self):
        self.write("pong\n")

if __name__ == "__main__":
    application = tornado.web.Application([ ("/ping", PingHandler), ])
    application.listen(8888)
    tornado.ioloop.IOLoop.instance().start()

Tornado 不断向 stderr 报告错误请求:

WARNING:tornado.access:404 GET / (127.0.0.1) 0.79ms

问题:它想阻止它记录错误信息。怎么办？

Tornado 版本 3.1； Python 2.6

Answer 1

很明显，当我们启动 Tornado 时，“某人”正在初始化日志子系统。以下是来自 ioloop.py 的代码揭示了其中的奥秘:

def start(self):
    if not logging.getLogger().handlers:
        # The IOLoop catches and logs exceptions, so it's
        # important that log output be visible.  However, python's
        # default behavior for non-root loggers (prior to python
        # 3.2) is to print an unhelpful "no handlers could be
        # found" message rather than the actual log entry, so we
        # must explicitly configure logging if we've made it this
        # far without anything.
        logging.basicConfig()

basicConfig 被调用并配置默认的 stderr 处理程序。

因此，要为 tonado 访问设置正确的日志记录，您需要:

1. 将处理程序添加到 tornado.access 记录器:logging.getLogger("tornado.access").addHandler(...)

2. 禁用上述记录器的传播:logging.getLogger("tornado.access").propagate = False。否则消息将同时到达您的处理程序和 stderr