Some profiling helpers for Python and Django

import time
from django.db import connection
from django.conf import settings
from contextlib import contextmanager


def timer(what=None):
    """
    This decorator count the number of seconds
    it takes to run the decorated function.
    It also can be used as a context manager
    """

    # ignore in production
    if not settings.DEBUG:
        return what

    @contextmanager
    def benchmark(name):
        start_time = time.time()
        yield
        secs = time.time() - start_time
        print 'execution of %s: %.2f seconds' % (name, secs)

    if hasattr(what, "__call__"):
        def wrapped_function(*args, **kwargs):
            with benchmark('function "%s"' % what.__name__):
                return what(*args, **kwargs)
        wrapped_function.__doc__ = what.__doc__
        wrapped_function.__name__ = what.__name__
        return wrapped_function
    else:
        return benchmark(('block "%s"' % what) if what else "anonymous block")


def queries_counter(what=None):
    """
    This decorator count the number of database queries
    performed by Django during the execution of the decorated function.
    It also can be used as a context manager.
    """

    # ignore in production
    if not settings.DEBUG:
        return what

    @contextmanager
    def benchmark(name):
        num_queries_before = len(connection.queries)
        yield
        num_queries = len(connection.queries) - num_queries_before
        print 'execution of %s: %d queries performed' % (name, num_queries)

    if hasattr(what, "__call__"):
        def wrapped_function(*args, **kwargs):
            with benchmark('function "%s"' % what.__name__):
                return what(*args, **kwargs)
        wrapped_function.__doc__ = what.__doc__
        wrapped_function.__name__ = what.__name__
        return wrapped_function
    else:
        return benchmark(('block "%s"' % what) if what else "anonymous block")

# Usage:
# @timer
# def my_function():
#     x = 0
#     for i in range(1, 100000):
#         x += i
#     return x
#
# >>> print my_function()
# execution of function "my_function": 0.02 seconds
# 4999950000


# >>> with timer():
# >>>     x = 0
# >>>     for i in range(100000):
# >>>         x += i
#
# execution of anonymous block: 0.01 seconds


# >>> with timer("my block"):
# >>>     x = 0
# >>>     for i in range(100000):
# >>>         x += i
#
# execution of block "my block": 0.01 seconds


# >>> with queries_counter():
# >>>     print Country.objects.count()
#
# execution of anonymous block: 1 queries performed