philiprehberger-di 0.2.0

Lightweight dependency injection container for Python.

philiprehberger-di

Lightweight dependency injection container for Python.

Installation

pip install philiprehberger-di

Usage

from philiprehberger_di import Container

container = Container()
container.register(Logger)
logger = container.resolve(Logger)

Singletons

container.register(Database, singleton=True)

a = container.resolve(Database)
b = container.resolve(Database)
assert a is b

Custom Factories

container.register(Cache, factory=lambda: Cache(max_size=256))
cache = container.resolve(Cache)

Recursive Resolution

class Service:
    def __init__(self, db: Database, logger: Logger) -> None:
        self.db = db
        self.logger = logger

container.register(Database)
container.register(Logger)
container.register(Service)
service = container.resolve(Service)  # db and logger are injected automatically

Inject Decorator

from philiprehberger_di import Container, inject

container = Container()
container.register(Logger, singleton=True)

@inject(container)
def handle_request(logger: Logger) -> str:
    logger.log("request handled")
    return "ok"

handle_request()  # logger is resolved and injected automatically

Lifecycle Hooks

container.register(
    Database,
    singleton=True,
    on_create=lambda db: db.connect(),
    on_destroy=lambda db: db.disconnect(),
)

db = container.resolve(Database)  # on_create called after creation
container.reset()                 # on_destroy called before clearing singletons

API

Function / Class	Description
Container()	Create a new dependency injection container
container.register(cls, factory?, singleton?, on_create?, on_destroy?)	Register a class with optional factory, singleton flag, and lifecycle hooks
container.resolve(cls)	Resolve an instance, recursively injecting dependencies
container.reset()	Call on_destroy for singletons with hooks, then clear the cache
inject(container)	Decorator that resolves type-hinted params from the container

Development

pip install -e .
python -m pytest tests/ -v

Support

If you find this package useful, consider starring the repository.

License

MIT