attodi 0.0.10

Minimalistic DI library for python.

Attodi

Minimalistic DI library for python

Attodi is a small dependency-injection container for Python. You register types (and optionally concrete implementations or pre-built instances) on a ServiceCollection, then resolve fully-constructed instances from a ServiceProvider, which builds constructor arguments automatically from type hints.

Requirements

• Python >= 3.12

Installation

pip install attodi

Usage

from attodi.core import ServiceCollection, ServiceProvider

class Greeter:
    def __init__(self, name: str):
        self.name = name

    def greet(self) -> str:
        return f"Hello, {self.name}!"

services = ServiceCollection()
services.add_singleton(str, service="World")
services.add_singleton(Greeter)

provider = ServiceProvider(services)
greeter = provider.get_service(Greeter)
print(greeter.greet())  # Hello, World!

ServiceProvider inspects the constructor of the class being resolved, matches its parameter type hints against registered services, resolves them recursively, and instantiates the class with the results.

Service lifetimes

Register services with one of three lifetimes:

Method	Lifetime	Behavior
add_singleton(cls, concrete=None, service=None)	Singleton	One shared instance per ServiceProvider (or a pre-built service value).
add_scoped(cls, concrete=None)	Scoped	One shared instance per scope (see create_scope).
add_transient(cls, concrete=None)	Transient	A new instance every time it is resolved.

services = ServiceCollection()
services.add_scoped(Database)

provider = ServiceProvider(services)
scope = provider.create_scope()
db = scope.get_service(Database)

Resolving multiple registrations

get_service returns the first matching registration; get_services returns an iterator over every registration that matches a type (including subclasses).

for service in provider.get_services(Person):
    ...

License

GPL-3.0