in-n-out

0.2.1 verified Mon Apr 27 auth: no python

A plugable dependency injection and result processing library for Python. Current version 0.2.1, released June 2025. Active development with monthly releases.

pip install in-n-out

Common errors

error ModuleNotFoundError: No module named 'in_n_out' ↓

cause Library not installed or Python environment mismatch.

fix

Run pip install in-n-out and ensure you are using Python >=3.8.

error TypeError: 'NoneType' object is not callable ↓

cause Return value from `processor.process()` is None because no registered processor handles the function's return type.

fix

error AttributeError: module 'in_n_out' has no attribute 'Injector' ↓

cause Incorrect import path; the class is exported from the top-level package.

fix

Use from in_n_out import Injector or import in_n_out; injector = in_n_out.Injector().

Warnings

deprecated The `register` decorator with both Injector and Processor on the same function is deprecated; use `@injector.register` and `@processor.register` separately. ↓

fix Decorate the function twice, once per instance.

gotcha Processor returns a coroutine object if the function is async; you must await it. ↓

fix Use `await processor.process(...)` for async functions.

breaking Before v0.2.0, the `inject` decorator existed; it was removed and replaced with `Injector.register`. ↓

fix Upgrade to 0.2.x and use `Injector.register`.

Imports

Injector
```
from in_n_out import Injector
```
Processor
```
from in_n_out import Processor
```
intake
```
from in_n_out import intake
```

Quickstart

Simple dependency injection and result processing example.

from in_n_out import Injector, Processor, intake

class MyService:
    def greet(self, name: str) -> str:
        return f"Hello, {name}!"

injector = Injector()
processor = Processor()

@injector.register
@processor.register
def my_function(name: str) -> str:
    service = MyService()
    return service.greet(name)

result = processor.process(my_function, name="World")
print(result)