PYGRL - Python General Rate Limiter

Another Python package aim to offer "Rate Limiting" functionality for general use cases.

Features

• Flexible storage strategy (Memory | File | Database)
  • MemoryStorage
    • BasicStorage
  • FileStorage
    • SQLite3_Storage
• Cleanup expired rate limiters
• Use as a decorator
• Use as a variable
• Compatible with fastapi (TO BE TESTED)
• Support asynchronous DB operations (TODO)

Dependencies

• Python 3.10

Installation

pip3 install pygrl

Example - BasicStorage

Imports

from pygrl import BasicStorage, GeneralRateLimiter as grl, ExceededRateLimitError

Check limit with BasicStorage

storage = BasicStorage()
rate_limiter = grl(storage, 10, 1)
try:
    for i in range(12):
        allowed_to_pass = rate_limiter.check_limit("client-key")
        if allowed_to_pass:
            print(f"Request {i + 1}: Allowed")
        else:
            print(f"Request {i + 1}: Exceeded rate limit")
except Exception as e:
    print(f"Rate limit exceeded: {e}")

Apply rate limiter decorator with BasicStorage

@grl.general_rate_limiter(storage=BasicStorage(), max_requests=10, time_window=1)
def fn(a, b):
    return a + b

try:
    for i in range(12):
        result = fn(i, i + 1)
        print(f"Result {i + 1}: {result}")
except ExceededRateLimitError as e:
    print(f"Rate limit exceeded: {e}")

Apply rate limiter decorator with BasicStorage (Keyed function)

import random

@grl.general_rate_limiter(storage=BasicStorage(), max_requests=2, time_window=1)
def connect(key: str, host: str, port: int):
    return f"{key} connected to {host}:{port}"

users = ["Alice", "Bob", "Charlie", "David", "Eve"]
try:
    for i in range(12):
        user = random.choice(users)
        result = connect(key=user, host="localhost", port=3306)
        print(f"Result: {result}")
except ExceededRateLimitError as e:
    print(f"Rate limit exceeded: {e}")

Apply rate limiter decorator with BasicStorage (key_builder with arguments)

import random

# Take all arguments to construct the key!
key_builder = lambda f, *args, **kwargs: ",".join(list(map(lambda x: str(x), args)))

@grl.general_rate_limiter(
    storage=BasicStorage(), 
    max_requests=2, 
    time_window=1, 
    key_builder=key_builder
)
def connect(username: str, host: str, port: int, *args):
    return f"{username} connected to {host}:{port}"

users = ["Alice", "Bob", "Charlie", "David", "Eve"]
try:
    for i in range(12):
        user = random.choice(users)
        result = connect(user, "localhost", 3306)
        # Modify the function call like below would make every call unique, 
        # thus never trigger the `ExceedRateLimitError`.
        # result = connect(user, "localhost", 3306, i) # `i` is unique
        print(f"Result: {result}")
except ExceededRateLimitError as e:
    print(f"Rate limit exceeded: {e}")

Apply rate limiter decorator with BasicStorage (key_builder with keyword argument)

import random

@grl.general_rate_limiter(
    storage=BasicStorage(), 
    max_requests=2, 
    time_window=1, 
    key_builder=lambda f, *args, **kwargs: kwargs["username"]
)
def connect(username: str, host: str, port: int):
    return f"{username} connected to {host}:{port}"

users = ["Alice", "Bob", "Charlie", "David", "Eve"]
try:
    for i in range(12):
        user = random.choice(users)
        result = connect(username=user, host="localhost", port=3306)
        print(f"Result: {result}")
except ExceededRateLimitError as e:
    print(f"Rate limit exceeded: {e}")

Example - SQLite3_Storage

Imports

from pygrl import SQLite3_Storage, GeneralRateLimiter as grl, ExceededRateLimitError

Check limit with SQLite3_Storage

storage = SQLite3_Storage("storage1.db", overwrite=True)
rate_limiter = grl(storage, 10, 1)
try:
    for i in range(12):
        allowed_to_pass = rate_limiter.check_limit("client-key")
        if allowed_to_pass:
            print(f"Request {i + 1}: Allowed")
        else:
            print(f"Request {i + 1}: Exceeded rate limit")
except Exception as e:
    print(f"Rate limit exceeded: {e}")

Apply rate limiter decorator with SQLite3_Storage

@grl.general_rate_limiter(storage=SQLite3_Storage("storage2.db", overwrite=True), max_requests=10, time_window=1)
def fn(a, b):
    return a + b

try:
    for i in range(12):
        result = fn(i, i + 1)
        print(f"Result {i + 1}: {result}")
except ExceededRateLimitError as e:
    print(f"Rate limit exceeded: {e}")

Apply rate limiter decorator with SQLite3_Storage (Keyed function)

import random

@grl.general_rate_limiter(storage=SQLite3_Storage("storage3.db", overwrite=True), max_requests=2, time_window=1)
def connect(key: str, host: str, port: int):
    return f"{key} connected to {host}:{port}"

users = ["Alice", "Bob", "Charlie", "David", "Eve"]
try:
    for i in range(12):
        user = random.choice(users)
        result = connect(key=user, host="localhost", port=3306)
        print(f"Result: {result}")
except ExceededRateLimitError as e:
    print(f"Rate limit exceeded: {e}")

Apply rate limiter decorator with SQLite3_Storage (key_builder with arguments)

import random

# Take all arguments to construct the key!
key_builder = lambda f, *args, **kwargs: ",".join(list(map(lambda x: str(x), args)))

@grl.general_rate_limiter(
    storage=storage=SQLite3_Storage("storage3.db", overwrite=True), 
    max_requests=2, 
    time_window=1, 
    key_builder=key_builder
)
def connect(username: str, host: str, port: int, *args):
    return f"{username} connected to {host}:{port}"

users = ["Alice", "Bob", "Charlie", "David", "Eve"]
try:
    for i in range(12):
        user = random.choice(users)
        result = connect(user, "localhost", 3306)
        # Modify the function call like below would make every call unique, 
        # thus never trigger the `ExceedRateLimitError`.
        # result = connect(user, "localhost", 3306, i) # `i` is unique
        print(f"Result: {result}")
except ExceededRateLimitError as e:
    print(f"Rate limit exceeded: {e}")

Apply rate limiter decorator with SQLite3_Storage (key_builder with keyword argument)

import random

@grl.general_rate_limiter(
    storage=storage=SQLite3_Storage("storage3.db", overwrite=True), 
    max_requests=2, 
    time_window=1, 
    key_builder=lambda f, *args, **kwargs: kwargs["username"]
)
def connect(username: str, host: str, port: int):
    return f"{username} connected to {host}:{port}"

users = ["Alice", "Bob", "Charlie", "David", "Eve"]
try:
    for i in range(12):
        user = random.choice(users)
        result = connect(username=user, host="localhost", port=3306)
        print(f"Result: {result}")
except ExceededRateLimitError as e:
    print(f"Rate limit exceeded: {e}")

Source Code

• https://github.com/JonahTzuChi/rate-limiter