python logging timer decorator

example.py

import logging, time
from timer import timed

logger = logging.getLogger()
logger.setLevel(logging.DEBUG)

handler = logging.StreamHandler()
handler.setLevel(logging.DEBUG)
logger.addHandler(handler)

@timed(logger)
def pow10(x):
    time.sleep(1)
    return x ** 10

# will log: <function pow10 at 0x107847230>: 1001.08790398 ms
pow10(100)

timer.py

import functools
import logging
import time


def timed(logger, level=None, format='%s: %s ms'):
    if level is None:
        level = logging.DEBUG

    def decorator(fn):
        @functools.wraps(fn)
        def inner(*args, **kwargs):
            start = time.time()
            result = fn(*args, **kwargs)
            duration = time.time() - start
            logger.log(level, format, repr(fn), duration * 1000)
            return result
        return inner

    return decorator