independency 1.2

Dependency injection container

Independency

Independency is a DI container library. Unlike many other Python DI containers Independency operates in the local scope. It's inspired by punq, so the API is very similar.

Independency supports generics and other specific typings.

Installation

pip install independency

Quick start

Independency avoids global state, so you must explicitly create a container in the entrypoint of your application:

import independency

builder = independency.ContainerBuilder()
# register application dependencies
container = builder.build()

Examples

import requests

from independency import Container, ContainerBuilder


class Config:
    def __init__(self, url: str):
        self.url = url


class Getter:
    def __init__(self, config: Config):
        self.config = config

    def get(self):
        return requests.get(self.config.url)


def create_container() -> Container:
    builder = ContainerBuilder()
    builder.singleton(Config, Config, url='http://example.com')
    builder.singleton(Getter, Getter)
    return builder.build()


def main():
    container = create_container()
    getter: Getter = container.resolve(Getter)
    print(getter.get().status_code)


if __name__ == '__main__':
    main()

Suppose we need to declare multiple objects of the same type and use them correspondingly.

from independency import Container, ContainerBuilder, Dependency as Dep


class Queue:
    def __init__(self, url: str):
        self.url = url

    def pop(self):
        ...

    
class Consumer:
    def __init__(self, q: Queue):
        self.queue = q

    def consume(self):
        while True:
            message = self.queue.pop()
            # process message


def create_container() -> Container:
    builder = ContainerBuilder()
    builder.singleton('first_q', Queue, url='http://example.com')
    builder.singleton('second_q', Queue, url='http://example2.com')
    builder.singleton('c1', Consumer, q=Dep('first_q'))
    builder.singleton('c2', Consumer, q=Dep('second_q'))
    return builder.build()


def main():
    container = create_container()
    consumer: Consumer = container.resolve('c1')
    consumer.consume()


if __name__ == '__main__':
    main()