PyInject

PyInject is a Python library for dependency injection.

It is inspired by the FastAPI dependency framework.

Installation

Requires Python 3.10 or higher.

You can install with pip install git+https://github.com/xpinked/pyinject.git.

Basic Usage

Lets define some services

In this example we will define two services, ServiceA and ServiceB.

will be in a module called services.py.

class ServiceA:
    name = "ServiceA"

    def hello(self):
        return f"Hello from {self.name}"

class ServiceB:
    name = "ServiceB"

    def hello(self):
        return f"Hello from {self.name}"

class ServiceC:
    name = "ServiceC"

    def hello(self):
        return f"Hello from {self.name}"

def get_service_c():
    return ServiceC()

---

Lets use these services

Lets say we want to use these services in a function.

from typing import Annotated
from pyinject import AutoWired, Depends, execute

from .services import ServiceA, ServiceB

@AutoWired()
def func(service_a: Annotated[ServiceA, Depends()], service_b: Annotated[ServiceB, Depends()]):
    print(service_a.hello())
    print(service_b.hello())

if __name__ == "__main__":
    execute(func)

We have to use the AutoWired decorator to tell the dependency injector that this function should be executed with all its dependencies injected.

and we have to use the Annotated type hint to tell the dependency injector what type of dependency we want to inject.

The Depends class is used to tell the dependency injector that we want to inject a dependency,

and we used the execute function to execute the function with all its dependencies injected.

This will print:

Hello from ServiceA
Hello from ServiceB

if we do not provide a type hint for the dependency, the dependency injector will try to infer the type from the type hint of the variable.

Otherwise, we can provide a provider function to the Depends class, which will be used to provide the dependency.

from typing import Annotated
from pyinject import AutoWired, Depends, execute

from .services import ServiceC, get_service_c

@AutoWired()
def func_2(service_c: Annotated[ServiceC, Depends(get_service_c)]):
    print(service_c.hello())

if __name__ == "__main__":
    execute(func2)

This will print:

Hello from ServiceC

More Advanced Usage

You can checkout more code examples in Examples

License

This project is licensed under the terms of the MIT license.