Dependency injection for Typer

Add dependency injection functionality to Typer library. Implement the same DI behavior as in FastAPI.

Description

With typer_di you can easely move common parts of your commands to dependency functions.

Any dependency function can depends on other functions and etc. All args and options will be merged to interface of each command that uses corresponding dependencies.

typer_di ensures to call each dependency callback only once.

Usage

Lets say you have a method that validates and parses a config:

def get_config(config_path: Path) -> Config:
    ...

In case of multiple commands you need to duplicate annotation code:

from typing import Annotated
from typer import Typer, Option

app = Typer()

@app.command()
def first(..., config_path: Annotated[Path, Option("--config")]):
    config = get_config(config_path)
    ...

@app.command()
def second(..., config_path: Annotated[Path, Option("--config")]):
    config = get_config(config_path)
    ...

With typer_di you can move annotations to parsing methods.

All you need is to use Depends annotation and replace the original Typer by TyperDI (it's a thin layer that transforms all passed functions unwrapping dependencies).

from typing import Annotated
from typer import Option
from typer_di import TyperDI, Depends

app = TyperDI()

def get_config(config_path: Annotated[Path, Option("--config")]) -> Config:
    ...

@app.command()
def first(..., config: Config = Depends(get_config)):
    ...

@app.command()
def second(..., config: Config = Depends(get_config)):
    ...

Release Notes

v0.1.2

• add py.typed marker to the package

v0.1.1

• fix invalid validation for duplicated names
• check for loops in dependency graph

v0.1.0

• first public version
• support py37+