Decorator that prevents a function from being called more than the request limit every time period.

request_throttler.py

import json
from datetime import datetime, timedelta
from functools import wraps


class throttle(object):
    """
    Decorator that prevents a function from being called more than the request limit every
    time period.
    To create a function that cannot be called more than 10 ten time in a minute:
        @throttle(requests_limit=10, minutes=1)
        def my_fun():
            pass
    """
    def __init__(self, requests_limit=10, seconds=0, minutes=0, hours=0):
        self.throttle_period = timedelta(
            seconds=seconds, minutes=minutes, hours=hours
        )
        self.time_of_last_call = datetime.min
        self.requests_limit = requests_limit

    def __call__(self, fn):
        @wraps(fn)
        def wrapper(*args, **kwargs):
            now = datetime.now()
            time_since_last_call = now - self.time_of_last_call

            if time_since_last_call > self.throttle_period:
                self.requests_limit = 0
                
            if self.requests_limit < 10:
                self.time_of_last_call = now
                self.requests_count += 1
                return fn(*args, **kwargs)
            else:
                return {"message": "LIMIT REACHED", "statusCode": 429}

        return wrapper
        

        
@throttle(requests_limit=10, seconds=30)
def lambda_handler(event, context):
    return {
        'statusCode': 200,
        'body': json.dumps('Hello from Lambda!')
    }