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A simple plugin system for async applications

Project description

aiohook – simple plugins for asyncio, trio and curio

aiohooks is a small library meant to help implementing a plugin system in Python 3.7+ asynchronous applications developed with an anyio-compatible library.


  • Declare the signature of the hook coroutine by decorating a dummy def (without implementation, or with a default one) with aiohook.spec.
  • await the dummy coroutine where you would want the plugin one to be called.
  • Implement the dummy coros in a separate module or class and decorate them with aiohook.impl('').
  • Call aiohook.register(reference) to register the decorated implementations in reference (object instance or module).
  • Non-implemented hooks result in the default implementation being called.
  • Registering multiple implementations of the same hook raises an exception.

Basic usage

In this story, your name is Wallace, you are implementing an awesome async application accepting plugins. Your user, Gromit, wants to make use of your plugin system to inject his custom parsing logic.

Application designer

You must first define the signature of each hook function, for instance in a separate file:

from typing import Sequence, Optional
import aiohook

async def tokenize(sentence: str) -> Sequence[str]:
    # Describe the purpose of the hook, arguments etc in the docstring
    """Split string of characters into individual tokens."""
    # No implementation here, this is just a function spec

async def transform_token(word: str) -> Optional[str]:
    """Preprocess each raw token, for instance as a normalization step."""

In your application code, you then call your spec'ed out functions as if they had already been implemented:

import sys
from pluginspecs import tokenize, transform_token

with open(sys.argv[1], 'r') as f:

Plugin developer


Two requirements files are used to describe the development setup:

  • The requirements.txt file describes a working development environment with all pinned dependencies.
  • The requirements-base.txt file contains the direct unpinned dependencies only.

Testing with coverage

pytest --cov=aiohook tests/

Project details

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aiohook-0.1.1.tar.gz (8.1 kB view hashes)

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