Timer decorator / context manager

timer.py

import time
import functools


class timer(object):
    """
    Usage

    As decorator:

    @timer()
    def my_function():
        # do something

    As context manager

    def my_function():
        with timer('doing something'):
            # do something
    """

    def __init__(self, name=None):
        self.name = name

    def __enter__(self):
        self.start = time.clock()
        return self

    def __exit__(self, *args):
        self.end = time.clock()
        self.interval = self.end - self.start
        print '%s: %.3fs' % (self.name, self.interval)

    def __call__(self, func):
        self.name = self.name or func.__name__

        @functools.wraps(func)
        def decorated(*args, **kwds):
            with self:
                return func(*args, **kwds)

        return decorated