Chronometer
===========
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Yet another simple time measurement tool for Python. The goal of this
implementation is to avoid as much cruft as possible. The current version
is 72 lines of actual code long, leaving out blank, doc and comment lines.
Chronometer provides only functions to measure how much wall-clock time
has passed between starting and stopping the timer.
Nothing more. Nothing less.
Chronometer tries to stay accurate to the actual time spent between
starting and stopping the timer by utilizing a monotonic timer. According
to the linux manual a monotonic timer is subject to time adjustments so
it stays accurate but will never move backwards or jump. It will be
adjusted gradually and always moves forward as long as the system runs.
Examples
--------
Easy:
.. code-block:: python
import time
from chronometer import Chronometer
long_running_task = lambda: time.sleep(3.)
with Chronometer() as t:
long_running_task() # that will take a few seconds.
print('Phew, that took me {:.3f} seconds!'.format(float(t)))
Advanced:
.. code-block:: python
from time import sleep
from chronometer import Chronometer
counter = 0
def long_running_task_that_can_fail():
global counter
counter += 1
sleep(2.)
return counter > 3
with Chronometer() as t:
while not long_running_task_that_can_fail():
print('Failed after {:.3f} seconds!'.format(t.reset()))
print('Success after {:.3f} seconds!'.format(float(t)))
Ridiculous:
.. code-block:: python
import asyncio
from chronometer import Chronometer
class PingEchoServerProtocol(asyncio.StreamReaderProtocol):
def __init__(self):
super().__init__(asyncio.StreamReader(), self.client_connected)
self.reader, self.writer = None, None
self.latency_timer = Chronometer()
def client_connected(self, reader, writer):
self.reader, self.writer = reader, writer
asyncio.async(self.ping_loop())
asyncio.async(self.handler())
@asyncio.coroutine
def send(self, data):
self.writer.write(data.encode('utf-8') + b'\n')
yield from self.writer.drain()
@asyncio.coroutine
def ping_loop(self):
yield from asyncio.sleep(5.)
while True:
if self.latency_timer.stopped:
self.latency_timer.start()
yield from self.send('PING (send me PONG!)')
sleep_duration = max(2., 10. - self.latency_timer.elapsed)
yield from asyncio.sleep(sleep_duration)
@asyncio.coroutine
def handler(self):
while True:
data = (yield from self.reader.readline())
if data[:4] == b'PONG' and self.latency_timer.started:
yield from self.send(('Latency: {:.3f}s'
.format(self.latency_timer.stop())))
l = asyncio.get_event_loop()
@asyncio.coroutine
def startup():
s = (yield from l.create_server(lambda: PingEchoServerProtocol(),
host='localhost', port=2727))
print('Now telnet to localhost 2727')
yield from s.wait_closed()
l.run_until_complete(startup())