-
-
Save jose-neta/05a387a3090931e9d3c8dc133e523d9f to your computer and use it in GitHub Desktop.
How do you rate limit calls with aiohttp? https://quentin.pradet.me/blog/how-do-you-rate-limit-calls-with-aiohttp.html
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
#!/usr/bin/env python3 | |
import asyncio | |
import time | |
import aiohttp | |
START = time.monotonic() | |
class RateLimiter: | |
"""Rate limits an HTTP client that would make get() and post() calls. | |
Calls are rate-limited by host. | |
https://quentin.pradet.me/blog/how-do-you-rate-limit-calls-with-aiohttp.html | |
This class is not thread-safe.""" | |
RATE = 1 # one request per second | |
MAX_TOKENS = 10 | |
def __init__(self, client): | |
self.client = client | |
self.tokens = self.MAX_TOKENS | |
self.updated_at = time.monotonic() | |
async def get(self, *args, **kwargs): | |
await self.wait_for_token() | |
now = time.monotonic() - START | |
print(f'{now:.0f}s: ask {args[0]}') | |
return self.client.get(*args, **kwargs) | |
async def wait_for_token(self): | |
while self.tokens < 1: | |
self.add_new_tokens() | |
await asyncio.sleep(0.1) | |
self.tokens -= 1 | |
def add_new_tokens(self): | |
now = time.monotonic() | |
time_since_update = now - self.updated_at | |
new_tokens = time_since_update * self.RATE | |
if self.tokens + new_tokens >= 1: | |
self.tokens = min(self.tokens + new_tokens, self.MAX_TOKENS) | |
self.updated_at = now | |
async def fetch_one(client, i): | |
url = f'https://httpbin.org/get?i={i}' | |
# Watch out for the extra 'await' here! | |
async with await client.get(url) as resp: | |
resp = await resp.json() | |
now = time.monotonic() - START | |
print(f"{now:.0f}s: got {resp['args']}") | |
async def main(): | |
async with aiohttp.ClientSession() as client: | |
client = RateLimiter(client) | |
tasks = [asyncio.ensure_future(fetch_one(client, i)) for i in range(20)] | |
await asyncio.gather(*tasks) | |
if __name__ == '__main__': | |
# Requires Python 3.7+ | |
asyncio.run(main()) | |
# This work is licensed under the terms of the MIT license. | |
# For a copy, see <https://opensource.org/licenses/MIT>. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment