typedi 0.4.1

Simple yet powerful typed dependency injection container

typedi

Simple yet powerful typed dependency injection container.

To install from python package index simply type (no dependencies):

pip install typedi

Or if you don't want to bring a dependency inside your project simply copy and paste typedi.py file (and dont forget the tests).

Usage

Common usage scenario

config.py

from dataclasses import dataclass

@dataclass
class DatabaseConfig:
    host: str
    username: str
    password: str

@dataclass
class AppConfig:
    debug: bool = False 

app.py

from config import DatabaseConfig, AppConfig

class Application:
    def __init__(self, app_conf: AppConfig, db_config: DatabaseConfig):
        pass

    def run(self):
        pass

main.py

from typedi import container

from config import DatabaseConfig, AppConfig
from app import Application

def load_db_config_from_file() -> DatabaseConfig:
    # Load config from file... and intantiate a config object
    return DatabaseConfig(host='localhost', username='user', password='pass')

if __name__ == '__main__':
    container.register_singleton_factory(load_db_config_from_file)
    container.register_singleton_class(AppConfig)
    container.register_class(Application)

    # When accessing the instance typedi will automatically resolve all required dependencies
    # provided in __init__ annotations
    application_with_initialized_configs = container.get_instance(Application)
    application_with_initialized_configs.run()

Containers

typedi comes with a default shared container, to add or retrieve instances from it import it anywhere you need - usually in some initialization/bootstrapping logic.

from typedi import container

Or you could also create your own DI containers:

from typedi import Container

my_container = Container()

Instance bindings, "user-managed singletons"

from typedi import container

class MyClass:
    pass

instance = MyClass()
container.register_instance(instance)

# anywhere else
from typedi import container

instance = container.get_instance(MyClass)

Class bindings

from typedi import container

class MyClass:
    pass

container.register_class(MyClass)

# anywhere else
from typedi import container

auto_instantiated_instance = container.get_instance(MyClass)

Class bindings with inheritance

from typedi import container

class MyClass:
    pass

class ChildOfMyClass(MyClass):
    pass

container.register_class(ChildOfMyClass)

# anywhere else
from typedi import container

auto_instantiated_instance = container.get_instance(MyClass)  # type: ChildOfMyClass

Testing

We are using tox (and pytest) to test among multiple python versions. To run test suites and generate coverage reports simply execute

tox

If you don't have tox installed, execute pip install tox first.