zev/studying-rate-limiting
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token bucket implemented in memory, in app

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Zev Averbach
2023-08-10 12:28:09 +03:00
commit 224cc4f5ec
5 changed files with 59 additions and 0 deletions
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.gitignore vendored Normal file
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__pycache__/
env/
*.pyc

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my_limiter/__init__.py Normal file
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my_limiter/algos.py Normal file
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import datetime as dt
TOKEN_BUCKET = {}
TIME_INTERVAL_SECONDS = 15
class TooManyRequests(Exception):
pass
def token_bucket(ip: str):
"""
Tokens are put in the bucket at preset rates periodically.
Once the bucket is full, no more tokens are added.
The refiller puts NUM_TOKENS_TO_REFILL tokens into the bucket every minute.
"""
REFILL_EVERY_SECONDS = TIME_INTERVAL_SECONDS
NUM_TOKENS_TO_REFILL = 4
MAX_CAPACITY = 4
entry = TOKEN_BUCKET.get(ip)
if entry is None:
TOKEN_BUCKET[ip] = {'tokens': 4, 'last_refilled': dt.datetime.now().timestamp()}
else:
if dt.datetime.now().timestamp() >= entry['last_refilled'] + REFILL_EVERY_SECONDS:
entry['last_refilled'] = dt.datetime.now().timestamp()
entry['tokens'] = min(entry['tokens'] + NUM_TOKENS_TO_REFILL, MAX_CAPACITY)
left = TOKEN_BUCKET[ip]['tokens']
if left == 0:
raise TooManyRequests
TOKEN_BUCKET[ip]['tokens'] -= 1

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my_limiter/config.py Normal file
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my_limiter/wsgi.py Normal file
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import flask as f
from . import algos
application = f.Flask(__name__)
increment_requests_func = algos.token_bucket
@application.before_request
def before_request():
ip = f.request.remote_addr
try:
increment_requests_func(ip)
except algos.TooManyRequests:
return f.abort(429)
@application.route('/')
def home():
return '<!doctype html><title>Hello</title><h1>Hello</h1>'