Use decorators to set a service definition

[shiroyuki]

While XML is a powerful ML, not many people like working with XML. So, there are a few feedbacks on how writing service definition can be improved.

Instead of using XML, we borrow the idea of component scanning from Spring Beans by allowing developers to define the definitions in Python (beside #21).

# the ready-to-go standalone container already implemented
from imagination.standalone import container

container.configure('myapp.config')
container.configure('library_1.config')
# ...
container.configure('library_n.config')

from imagination.decorators import config

@config(scan=['myapp.submodule_1', '...', 'myapp.submodule_n'])
class MyAppConfigurationA:
    # ...

from imagination.decorator.stereotype  import component

@component
class Dependency1Class:
      # ...

from imagination.decorator import auto_wired
from imagination.decorator.stereotype  import component, identifier

@auto_wired
@component
@identifier('myapp.service.one')
class Service1:
      dependency1: Dependency1Class

This is borrowed the idea from Flask and the presumably discontinued Spring-Python.

[shiroyuki]

In the 3.0.0-dev.1 release, the code will look like this.

from imagination import service
from imagination.decorator.config import (default_id_by_fully_qualify_class_name,
                                          default_id_by_shorten_fully_qualify_class_name,
                                          default_id_by_qualify_class_name,
                                          default_id_by_class_name,
                                          Parameter as PrimitiveParameter,
                                          Service as ServiceParameter)

@service.registered(
    params=[
        PrimitiveParameter('Panda', 'name'),
        ServiceParameter(SimpleSampleService, 'simple_sample', default_id_by_class_name),
    ],
    default_service_id_generator=default_id_by_class_name
)
class Foo:
    # ...

However, the end goal should be something like:

@generate_service_id(by_class_name)
@inject(SimpleSampleService, 'simple_sample')
@define(name='Panda')
@service.registered
class Foo:
    simple_sample:SimpleSampleService
    # ...

[shiroyuki]

The commit c3b994c should resolve the basic requirement for this issue. Until there is a proper documentation, please check out https://github.com/shiroyuki/Imagination/blob/master/test/v3/test_imagination_decorator_config.py for sample usage.

[shiroyuki]

Service scanning is required for this task.