Decorator

from ratelimiter import RateLimiter

@RateLimiter(max_calls=10, period=1)
def do_something():
    pass

Context Manager

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.

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.

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())