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|
RateLimiter
===========
|PyPI Version| |Build Status| |Python Version| |License|
Simple Python module providing rate limiting.
Overview
--------
This package provides the ``ratelimiter`` module, which ensures that an
operation will not be executed more than a given number of times on a
given period. This can prove useful when working with third parties APIs
which require for example a maximum of 10 requests per second.
Usage
-----
Decorator
~~~~~~~~~
.. code:: python
from ratelimiter import RateLimiter
@RateLimiter(max_calls=10, period=1)
def do_something():
pass
Context Manager
~~~~~~~~~~~~~~~
.. code:: python
from ratelimiter import RateLimiter
rate_limiter = RateLimiter(max_calls=10, period=1)
for i in range(100):
with rate_limiter:
do_something()
Callback
~~~~~~~~
The callback is called in its own thread, so your callback may use
``sleep`` without delaying the rate limiter.
.. code:: python
import time
from ratelimiter import RateLimiter
def limited(until):
duration = int(round(until - time.time()))
print('Rate limited, sleeping for {:d} seconds'.format(duration))
rate_limiter = RateLimiter(max_calls=2, period=3, callback=limited)
for i in range(3):
with rate_limiter:
print('Iteration', i)
Output:
::
Iteration 0
Iteration 1
Rate limited, sleeping for 3 seconds
Iteration 2
asyncio
~~~~~~~
The ``RateLimiter`` object can be used in an ``async with`` statement on
Python 3.5+. Note that the callback must be a coroutine in this context.
The coroutine callback is not called in a separate thread.
.. code:: python
import asyncio
import time
from ratelimiter import RateLimiter
async def limited(until):
duration = int(round(until - time.time()))
print('Rate limited, sleeping for {:d} seconds'.format(duration))
async def coro():
rate_limiter = RateLimiter(max_calls=2, period=3, callback=limited)
for i in range(3):
async with rate_limiter:
print('Iteration', i)
loop = asyncio.get_event_loop()
loop.run_until_complete(coro())
License
-------
| Original work Copyright 2013 Arnaud Porterie
| Modified work Copyright 2016 Frazer McLean
Licensed under the Apache License, Version 2.0 (the “License”); you may
not use this file except in compliance with the License. You may obtain
a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an “AS IS” BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
.. |PyPI Version| image:: http://img.shields.io/pypi/v/ratelimiter.svg?style=flat-square
:target: https://pypi.python.org/pypi/ratelimiter
.. |Build Status| image:: http://img.shields.io/travis/RazerM/ratelimiter/master.svg?style=flat-square
:target: https://travis-ci.org/RazerM/ratelimiter
.. |Python Version| image:: https://img.shields.io/badge/python-2.7%2C%203-brightgreen.svg?style=flat-square
:target: https://www.python.org/downloads/
.. |License| image:: http://img.shields.io/badge/license-Apache-blue.svg?style=flat-square
:target: https://github.com/RazerM/ratelimiter/blob/master/LICENSE
|
