di

A lightweight and extensible Dependency Injection (DI) framework for Python.

This project offers a minimalistic yet powerful approach to defining and resolving dependencies in Python applications using container-based injection and class decorators for automatic registration.

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Features

• 📦 Component Registration — Use @component to register classes into a DI container.
• ⚙️ Method Injection — Use @autowired to inject dependencies into arbitrary methods or functions.
• 🔄 Automatic Dependency Resolution — Constructor dependencies are automatically resolved and injected.
• 🧱 Custom Containers — Manage multiple containers for different contexts or scopes.
• 🔍 Type-safe Lookup — Retrieve components by type using indexing, get_component, or get_optional_component.
• 🔒 Immutable Containers — Containers become immutable after first use to ensure consistent state.
• ⏳ Async Support — Works seamlessly with async def functions and methods, including @autowired injection.

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Installation

Use the di.aio module for asyncio-compatible dependency injection in your project. The synchronous API is available in di and is documented in di/basic_container/README.md.

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Usage

For legacy usage examples without asyncio support, see: di/basic_container/README.md.

Example

This is an example of how to register components using decorators and autowiring.

import asyncio
from di.aio import component, autowired

@component
class AsyncService:
    async def fetch(self):
        await asyncio.sleep(0.1)
        return "Fetched async result"

class AsyncWorker:
    @autowired
    async def work(self, *, async_service: AsyncService):
        result = await async_service.fetch()
        print("Result:", result)

worker = AsyncWorker()
asyncio.run(worker.work())

The @autowired decorator can be used outside of classes as well

import asyncio
from di.aio import component, autowired

@component
class AsyncService:
    async def fetch(self):
        await asyncio.sleep(0.1)
        return "Fetched async result"

@autowired
async def work(self, *, async_service: AsyncService):
    result = await async_service.fetch()
    print("Result:", result)

asyncio.run(work())

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License

This project is licensed under the Eclipse Public License 2.0. See the LICENSE file for more details.