Broccoli is a simple dependency injection package based on type annotations

Installation

pip install broccoli

Features

• Simple - less than 100 lines of code without external dependencies
• Error check - Function signature check on start up - less errors during refactoring
• Fast - Designed to have zero runtime overhead, all dependencies injected either on module load or application start up.
• Powerful - Auto-discovery of dependencies by package and by module
• Convenient - Hackable and elegant programmatic API. Really easy to start using it.

Python 2 support?

Oups, sorry

Basic Usage

Inject dependency to function with type annotations

from broccoli import bind

class Dependency:
    pass

def foo(a, bar:Dependency):
    print(a, bar)

bind(foo, Dependency())
foo(1)  # prints 1 <__main__.Dependency object at 0x11111b7b8>

Inject dependency to module/package

# module foo.py

def foo(a, b:DependencyA):
    print(a, b)


def bar(a, b:DependencyB):
    print(a, b)

# main.py
from broccoli import inject
from package import foo

inject(foo, DependencyA(), DependencyB())

# or
inject('package.foo', DependencyA(), DependencyB())

Example with decorator wich inject deps on demand

from brocolli.fixtures.types import *
from broccoli import Dependency


def dependecies():
    return Db(), Service(), Cache()


default_dependencies = Dependency(dependecies)


@default_dependencies
def a(db: Db):
    return db.query('User').all()

Inject deps on application entry point

...

default_dependencies = Dependency()


@default_dependencies
def a(db: Db):
    return db.query('User').all()

if __name__ == '__main__':
    default_dependencies << dependecies
    # or even
    default_dependencies << dependecies()

Test examples

examples

This looks as dirty hack why should use it?

No reason, you can keep using module level variables and singleton objects. But if you know a good example of unit tests for such code don't hesitate to share it.

Getting Help

For feature requests and bug reports submit an issue to the GitHub issue tracker for Broccoli.