Welcome to PyDIO’s documentation!

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About PyDIO

PyDIO is a dependency injection library for Python.

It aims to be simple, yet still powerful, allowing you to feed dependencies inside your application in a flexible way. PyDIO design is based on simple assumption, that dependency injection can be achieved using simple key-to-function map, where key specifies type of object you want to inject and function is a factory function that creates instances of that type.

In PyDIO, this is implemented using providers and injectors. You use providers to configure your key-to-function mapping, and then you use injectors to perform a lookup of a specific key and creation of the final object.

Here’s a simple example:

import abc

from pydio.api import Provider, Injector

provider = Provider()

@provider.provides('greet')
def make_greet():
    return 'Hello, world!'

def main():
    injector = Injector(provider)
    greet_message = injector.inject('greet')
    print(greet_message)

And if you now call main() function, then the output will be following:

Hello, world!

Key features

  • Support for any hashable keys: class objects, strings, ints etc.

  • Support for any type of object factories: function, coroutine, generator, asynchronous generator.

  • Automatic resource management via generator-based factories (similar to pytest’s fixtures)

  • Multiple environment support: testing, development, production etc.

  • Limiting created object’s lifetime to user-defined scopes: global, application, use-case etc.

  • No singletons used, so there is no global state…

  • …but you still can create global injector on your own if you need it :-)

User’s Guide