limiter 0.2.0

⏲️ Rate-limiting, thread-safe and asynchronous decorators + context managers that implement the token-bucket algorithm.

limiter: Easy rate limiting for Python

limiter makes it easy to add rate limiting to Python projects, using a token bucket algorithm. limiter can provide Python projects and scripts with:

• Rate limiting thread-safe decorators
• Rate limiting async decorators
• Rate limiting thread-safe context-managers
• Rate limiting async context-managers

Here are a few benefits of using limiter:

• Easily control burst and average request rates
• limiter is thread-safe, with no need for a timer thread
• Has a simple API that takes advantage of Python's features, idioms and type hinting

Usage

You can define dynamic and static limiters, and use them across your project.

Dynamic limit

You can define a limiter with a set rate and capacity. Then you can consume a dynamic amount of tokens from different buckets using limit():

from limiter import get_limiter, limit


REFRESH_RATE: int = 2
BURST_RATE: int = 3
MSG_BUCKET: bytes = b'messages'


limiter = get_limiter(rate=REFRESH_RATE, capacity=BURST_RATE)


@limit(limiter)
def download_page(url: str) -> bytes:
    ...


@limit(limiter, consume=2)
async def download_page(url: str) -> bytes:
    ...


def send_page(page: bytes):
    with limit(limiter, consume=1.5):
        ...


async def send_page(page: bytes):
    async with limit(limiter):
        ...


@limit(limiter, bucket=MSG_BUCKET)
def send_email(to: str):
    ...


async def send_email(to: str):
    async with limit(limiter, bucket=MSG_BUCKET):
        ...

Static limit

You can define a static limit and share it between blocks of code:

limit_downloads = limit(limter, consume=2)


@limit_downloads
def download_page(url: str) -> bytes:
    ...


@limit_downloads
async def download_page(url: str) -> bytes:
    ...


def download_image(url: str) -> bytes:
    with limit_downloads:
        ...


async def download_image(url: str) -> bytes:
    async with limit_downloads:
        ...

Installation

Requirements

• Python 3.7+

Installing from PyPI

python3 -m pip install limiter

License

See LICENSE. If you'd like to use this project with a different license, please get in touch.