Knighted

Knighted, is heavily inspired by jeni and works only with asyncio. It allows to described dependencies, and inject them later.

For example:

from knighted import annotation, Injector

class MyInjector(Injector):
    pass

services = MyInjector()

@services.factory('foo')
def foo_factory():
    return 'I am foo'

@services.factory('bar')
def bar_factory():
    return 'I am bar'

@services.factory('all')
def together_factory():
    foo = yield from services.get('foo')
    bar = yield from services.get('bar')
    return [foo, bar]

@annotate('foo', 'bar')
def fun(foo, bar):
    return {'foo': foo,
            'bar': bar}

assert (yield from services.apply(fun)) == {'foo': 'I am foo',
                                            'bar': 'I am bar'}

The func() can be a function or an awaitable. These 2 examples works the same:

@annotate('foo', 'bar')
def sync_fun(foo, bar):
    return {'foo': foo,
            'bar': bar}

assert (yield from services.apply(sync_fun)) == {'foo': 'I am foo',
                                                 'bar': 'I am bar'}


@annotate('foo', 'bar')
async def awaitable_fun(foo, bar):
    return {'foo': foo,
            'bar': bar}

assert (yield from services.apply(awaitable_fun)) == {'foo': 'I am foo',
                                                      'bar': 'I am bar'}

When applied with some arguments, placeholders just fills the gaps:

@annotate('foo', 'bar')
def fun(foo, bar):
    return {'foo': foo,
            'bar': bar}

assert (yield from services.apply(fun, foo="yes")) == {'foo': 'yes',
                                                       'bar': 'I am bar'}


@annotate('foo', 'bar')
async def awaitable_fun(foo, bar):
    return {'foo': foo,
            'bar': bar}

assert (yield from services.apply(awaitable_fun)) == {'foo': 'I am foo',
                                                      'bar': 'I am bar'}

Factories also can be either sync or awaitable:

@services.factory('bar:sync')
def bar_factory():
    return 'I am bar'

@services.factory('bar:awaitable')
async def bar_factory():
    return 'I am bar'

Services are by default singleton, but they can also be instantiated at every call:

@services.factory('bar', singleton=True)
def bar_factory():
    return time()

result1 = await services.get('bar')
sleep(.1)
result2 = await services.get('bar')
assert result1 == result2

# cache can be resetted

services.refresh("bar")
result3 = await services.get('bar')
assert result3 != result2

Singleton mode can be disabled per service:

@services.factory('baz', singleton=False)
def baz_factory():
    return time()

result1 = await services.get('baz')
sleep(.1)
result2 = await services.get('baz')
assert result1 != result2

Current services are automatically exposed inside functions:

def func():
    return current_injector()

assert func() is None
assert (await services.apply(func)) is services

@services.factory('prefix')
def foo_factory(bar):
    return 'I am foo and ' + bar

assert (yield from services.get('prefix:baz')) == 'I am foo and baz'
assert (yield from services.get('prefix:qux')) == 'I am foo and qux'

class Foo:
    def close(self):
        self.closed = True
foo = Foo()
services.close.register(foo)
services.close()
assert foo.closed == True

@annotate('foo', 'bar')
def fun(foo, bar):
    return {'foo': foo,
            'bar': bar}

partial = services.partial(fun)
assert (yield from partial()) == {'foo': 'I am foo',
                                  'bar': 'I am bar'}

services["foo"] = "yes"
assert await services["foo"] == "yes"