debugging context manager

fsfds.py

import time, logging

class debug_watch:
    def __init__(self, name, logger=logging.info):
        self.name = name
        self.logger = logger

    def __enter__(self):
        self.t = time.time()
        self.logger("Starting %s" % self.name)

    def __exit__(self, *args):
        t = time.time() - self.t
        self.logger("Finished %s in %.3fs" % (self.name, t))

with debug_watch('some operation', logging.warning):
    print '"working"'
    time.sleep(2)

"""
WARNING:root:Starting some operation
"working"
WARNING:root:Finished some operation in 2.001s
"""