Clean IoC

A simple dependency injection library for python that requires nothing of your application code (except that you use typing).

Read the docs to find out more.

Basic Registering and resolving

There are 4 basic modes of registering a new set of classes

Implementation

class UserRepository(abc.ABC):
    @abc.abstractmethod
    def add(self, user):
        pass

class InMemoryUserRepository(UserRepository):

    def __init__(self):
        self.users = []

    def add(self, user):
        # This is obviously terrible, but it's for demo purposes
        self.users.append(user)

class SqlAlchemyUserRepository(UserRepository):

    def __init__(self):
        # Do some db stuff here
        pass

    def add(self, user):
        # Do some db stuff here
        pass

container = Container()
container.register(UserRepository, InMemoryUserRepository)


repository = container.resolve(UserRepository) # This will return an InMemoryUserRepository

Concrete Class

class ClientDependency:
    def get_int(self):
        return 10

class Client:
    def __init__(self, dep: ClientDependency):
        self.dep = dep

    def get_number(self):
        return self.dep.get_int()


container = Container()
container.register(ClientDependency)
container.register(Client)

client = container.resolve(Client)

client.get_number() # returns 10

Factory

class ClientDependency:
    def get_int(self):
        return 10

class Client:
    def __init__(self, dep: ClientDependency):
        self.dep = dep

    def get_number(self):
        return self.dep.get_int()

def client_factory(dep: ClientDependency):
    return Client(dep=dep)


container = Container()
container.register(ClientDependency)
container.register(Client, factory=client_factory)

client = container.resolve(Client)

client.get_number() # returns 10

Instance

class ClientDependency:
    def __init__(self, num):
        self.num = num

    def get_int(self):
        return self.num

class Client:
    def __init__(self, dep: ClientDependency):
        self.dep = dep

    def get_number(self):
        return self.dep.get_int()

client_dependency = ClientDependency(num=10)

container = Container()
container.register(ClientDependency, instance=client_dependency)
container.register(Client)

client = container.resolve(Client)

client.get_number() # returns 10