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https://github.com/Neoteroi/rodi
Implementation of dependency injection for Python 3
https://github.com/Neoteroi/rodi
dependency-injection python
Last synced: 6 days ago
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Implementation of dependency injection for Python 3
- Host: GitHub
- URL: https://github.com/Neoteroi/rodi
- Owner: Neoteroi
- License: mit
- Created: 2018-10-03T21:23:57.000Z (about 6 years ago)
- Default Branch: main
- Last Pushed: 2024-07-07T09:48:32.000Z (4 months ago)
- Last Synced: 2024-08-10T18:05:38.058Z (3 months ago)
- Topics: dependency-injection, python
- Language: Python
- Homepage:
- Size: 213 KB
- Stars: 175
- Watchers: 6
- Forks: 17
- Open Issues: 12
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
- awesome-dependency-injection-in-python - Rodi
- awesome-python-backend - _rodi_ - in DI container, less features and less Github activity (commits/contributors/etc.) but simpler to use (Topics Index / Commonly Useful Knowledge)
README
[](https://pypi.python.org/pypi/rodi)
[](https://github.com/Neoteroi/rodi)
[](https://codecov.io/gh/Neoteroi/rodi)
[](https://github.com/Neoteroi/rodi/blob/main/LICENSE)
# Implementation of dependency injection for Python 3
**Features:**
* types resolution by signature types annotations (_type hints_)
* types resolution by class annotations (_type hints_)
* types resolution by names and aliases (_convention over configuration_)
* unintrusive: builds objects graph **without** the need to change the
source code of classes
* minimum overhead to obtain services, once the objects graph is built
* support for singletons, transient, and scoped services
This library is freely inspired by .NET Standard
`Microsoft.Extensions.DependencyInjection` implementation (_ref. [MSDN,
Dependency injection in ASP.NET
Core](https://docs.microsoft.com/en-us/aspnet/core/fundamentals/dependency-injection?view=aspnetcore-2.1),
[Using dependency injection in a .Net Core console
application](https://andrewlock.net/using-dependency-injection-in-a-net-core-console-application/)_).
The `ContainerProtocol` for v2 is inspired by [punq](https://github.com/bobthemighty/punq).
## Installation
```bash
pip install rodi
```
## Efficient
`rodi` works by inspecting code **once** at runtime, to generate
functions that return instances of desired types - as long as the object graph
is not altered. Inspections are done either on constructors
(____init____) or class annotations. Validation steps, for
example to detect circular dependencies or missing services, are done when
building these functions, so additional validation is not needed when
activating services.
## Flexible
`rodi` offers two code APIs:
- one is kept as generic as possible, using a `ContainerProtocol` for scenarios
in which it is desirable being able to replace `rodi` with alternative
implementations of dependency injection for Python. The protocol only expects
a class being able to `register` and `resolve` types, and to tell if a type
is configured in it (`__contains__`). Even if other implementations of DI
don´t implement these three methods, it should be easy to use
[composition](https://en.wikipedia.org/wiki/Composition_over_inheritance) to
wrap other libraries with a compatible class.
- one is a more concrete implementation, for scenarios where it's not desirable
to consider alternative implementations of dependency injection.
For this reason, the examples report two ways to achieve certain things.
### Examples
For examples, refer to the [examples folder](./examples).
### Recommended practices
All services should be configured once, when an application starts, and the
object graph should *not* be altered during normal program execution.
Example: if you build a web application, configure the object graph when
bootstrapping the application, avoid altering the `Container` configuration
while handling web requests.
Aim at keeping the `Container` and service graphs abstracted from the front-end
layer of your application, and avoid mixing runtime values with container
configuration. Example: if you build a web application, avoid if possible
relying on the HTTP Request object being a service registered in your container.
## Service life style:
* singleton - instantiated only once per service provider
* transient - services are instantiated every time they are required
* scoped - instantiated only once per root service resolution call
(e.g. once per web request)
## Usage in BlackSheep
`rodi` is used in the [BlackSheep](https://www.neoteroi.dev/blacksheep/)
web framework to implement [dependency injection](https://www.neoteroi.dev/blacksheep/dependency-injection/) for
request handlers.
# Documentation
Under construction. 🚧