Rate limiting function calls with Python Decorators

rateLimitDecorator.py

import time

def RateLimited(maxPerSecond):
    minInterval = 1.0 / float(maxPerSecond)
    def decorate(func):
        lastTimeCalled = [0.0]
        def rateLimitedFunction(*args,**kargs):
            elapsed = time.clock() - lastTimeCalled[0]
            leftToWait = minInterval - elapsed
            if leftToWait>0:
                time.sleep(leftToWait)
            ret = func(*args,**kargs)
            lastTimeCalled[0] = time.clock()
            return ret
        return rateLimitedFunction
    return decorate

@RateLimited(2)  # 2 per second at most
def PrintNumber(num):
    print num

if __name__ == "__main__":
    print "This should print 1,2,3... at about 2 per second."
    for i in range(1,100):
        PrintNumber(i)

@oPromessa thanks for sharing and nice job on the logging and example.

Why dont you use a counter instead of a list. Each time the function is called, increment the counter by 1 and reset the counter to 0 when the second or minute has changed

Any updates regarding licensing of these pieces of code?

Note, there are other libraries on PyPI that do this, such as ratelimit

A more simple version but with async compatibility https://gist.github.com/hugokernel/c478d639849e1e772b1395a546100031

I created a similar asyncio version but using the token bucket algorithm for
max number of calls during/time interval which results in a maximum burst rate. it can be combined with the above rate limiter without burst rate..

https://gist.github.com/yeus/dff02dce88c6da9073425b5309f524dd

An extended version of @oPromessa 's utility. Thank you for sharing @oPromessa !