aiobreaker

aiobreaker is a Python implementation of the Circuit Breaker pattern, described in Michael T. Nygard’s book Release It!.

Circuit breakers exist to allow one subsystem to fail without destroying the entire system. This is done by wrapping dangerous operations (typically integration points) with a component that can circumvent calls when the system is not healthy.

This project is a fork of pybreaker by Daniel Fernandes Martins that replaces tornado with native asyncio, originally so I could practice packaging and learn about that shiny new typing package.

Features

  • Configurable list of excluded exceptions (e.g. business exceptions)

  • Configurable failure threshold and reset timeout

  • Support for several event listeners per circuit breaker

  • Can guard generator functions

  • Functions and properties for easy monitoring and management

  • asyncio support

  • Optional redis backing

  • Synchronous and asynchronous event listeners

Requirements

All you need is python 3.6 or higher.

Installation

To install, simply download from pypi:

pip install aiobreaker

Usage

The first step is to create an instance of CircuitBreaker for each integration point you want to protect against.

from aiobreaker import CircuitBreaker

# Used in database integration points
db_breaker = CircuitBreaker(fail_max=5, reset_timeout=timedelta(seconds=60))

@db_breaker
async def outside_integration():
    """Hits the api"""
    ...

At that point, go ahead and get familiar with the documentation.

General

Reference