Lunnaris-PyInject

Dependency injection library. Aims to be as simple as posible.

Usage

Using Dependency will create the object in every call.

# example.py
# import the dependency you need and the decorator 'inject'
from lunnaris_pyinject import Dependency, inject

class MyNeededDependency:
    def __init__(self, arg, other_arg):
        pass

# Supports *args and *kwargs
dependency = Dependency(MyNeededDependency,"some argument", other_arg="other arg")

@inject
def some_awesome_function(my_dependency: MyNeededDependency = dependency):
    # Do something cool with my_dependency
    pass

To use Singleton pattern

from lunnaris_pyinject import Dependency
class MyNeededDependency:
    pass
# Same code from above
# use is_singleton keyword argument
dependency = Dependency(MyNeededDependency, "one_argument", other_args=1, is_singleton=True)
# Same code

Take in count that is_singleton keyword argument is reserved and will be removed from the kwargs dictionary passed to the dependency.

You might want to use another object to hold all of your dependency creators.

# example.py
from lunnaris_pyinject import Dependency, DependantDependency, inject

class DB:
    pass


class Service:
    # No need to specify a default value, since it will be used 
    def __init__(self, db: DB):
        pass


class MyDependenciesHolder:
    # A simple dependency
    db = Dependency(DB, "connection_string", is_singleton=True)
    # Here a dependency can call another if the __init__ function is decorated with @inject
    service = DependantDependency(Service, db, is_singleton=True)

@inject
def some_func(service: Service = MyDependenciesHolder.service):
    pass