Dependency Injection

from pprint import pprint

from dicfg import ConfigReader, build_config

!cat ./configs/config.yml
config_reader = ConfigReader(name="myconfig")

default:
    config_int: 1
    config_string: "fire"
    config_list: [1, 2, 3]
    config_none: None
    config_dict:
        sub_config: "water"

To use dependency injection in our config we first need to setup a project with object dependencies.

class ProjectComponent:
    def __init__(self, name):
        self.name = name


class MyProject:
    def __init__(self, project_component: ProjectComponent):
        self.project_component = project_component

Objects can be build with build_config when using the *object key.

user_config = {
    "myconfig": {
        "default": {
            "project_component": {
                # a classes/functions can be build via the *object key
                "*object": "__main__.ProjectComponent",
                # any arguments can specified below
                "name": "my_project_component",
                # non-keyword arguments can be specified with *args, e.g.,
                # "*args": ["my_project_component"],
            },
        },
    },
}

config = config_reader.read(user_config)
pprint(config, sort_dicts=False)
objects = build_config(config["default"])

print("\n build objects: \n")

pprint(objects)

{'default': {'config_int': 1,
             'config_string': 'fire',
             'config_list': [1, 2, 3],
             'config_none': 'None',
             'config_dict': {'sub_config': 'water'},
             'project_component': {'*object': '__main__.ProjectComponent',
                                   'name': 'my_project_component'}}}

 build objects: 

{'config_dict': {'sub_config': 'water'},
 'config_int': 1,
 'config_list': [1, 2, 3],
 'config_none': None,
 'config_string': 'fire',
 'project_component': <__main__.ProjectComponent object at 0x7f1dc82a0df0>}

Dependency Injection can be done by object interpolation.

user_config = {
    "myconfig": {
        "default": {
            "project_component": {
                "*object": "__main__.ProjectComponent",
                "name": "my_project_component",
            },
            "project": {
                "*object": "__main__.MyProject",
                # object interpolation
                "project_component": "${project_component}",
            },
        },
    },
}

config = config_reader.read(user_config)
pprint(config, sort_dicts=False)
objects = build_config(config["default"])
print("\n build objects: \n")
pprint(objects, sort_dicts=False)
print("\nproject component name:", objects["project"].project_component.name)

{'default': {'config_int': 1,
             'config_string': 'fire',
             'config_list': [1, 2, 3],
             'config_none': 'None',
             'config_dict': {'sub_config': 'water'},
             'project_component': {'*object': '__main__.ProjectComponent',
                                   'name': 'my_project_component'},
             'project': {'*object': '__main__.MyProject',
                         'project_component': '${project_component}'}}}

 build objects: 

{'config_int': 1,
 'config_string': 'fire',
 'config_list': [1, 2, 3],
 'config_none': None,
 'config_dict': {'sub_config': 'water'},
 'project_component': <__main__.ProjectComponent object at 0x7f1dc82a0ac0>,
 'project': <__main__.MyProject object at 0x7f1dc82a0be0>}

project component name: my_project_component

Interpolation of objects is done by object reference.

user_config = {
    "myconfig": {
        "default": {
            "project_component": {
                "*object": "__main__.ProjectComponent",
                "name": "my_project_component",
            },
            "project": {
                "*object": "__main__.MyProject",
                # object interpolation by object reference
                "project_component": "${project_component}",
            },
            # object interpolation by object reference
            "my_interpolation_component": "${project_component}",
        },
    },
}

config = config_reader.read(user_config)
pprint(config, sort_dicts=False)
objects = build_config(config["default"])
print("\n build objects: \n")
pprint(objects, sort_dicts=False)

print("\nreference       project_component:", objects["project_component"])
print("reference interpolation_component:", objects["my_interpolation_component"])

{'default': {'config_int': 1,
             'config_string': 'fire',
             'config_list': [1, 2, 3],
             'config_none': 'None',
             'config_dict': {'sub_config': 'water'},
             'project_component': {'*object': '__main__.ProjectComponent',
                                   'name': 'my_project_component'},
             'project': {'*object': '__main__.MyProject',
                         'project_component': '${project_component}'},
             'my_interpolation_component': '${project_component}'}}

 build objects: 

{'config_int': 1,
 'config_string': 'fire',
 'config_list': [1, 2, 3],
 'config_none': None,
 'config_dict': {'sub_config': 'water'},
 'project_component': <__main__.ProjectComponent object at 0x7f1dc82a02b0>,
 'project': <__main__.MyProject object at 0x7f1dc82a08b0>,
 'my_interpolation_component': <__main__.ProjectComponent object at 0x7f1dc82a02b0>}

reference       project_component: <__main__.ProjectComponent object at 0x7f1dc82a02b0>
reference interpolation_component: <__main__.ProjectComponent object at 0x7f1dc82a02b0>

Object attribute interpolation is possible via accesing attributes of object references.

user_config = {
    "myconfig": {
        "default": {
            "project_component": {
                "*object": "__main__.ProjectComponent",
                "name": "my_project_component",
            },
            "project": {
                "*object": "__main__.MyProject",
                "project_component": "${project_component}",
            },
            "my_attribute_component": "${project_component}",
            # object attribute interpolation
            "my_attribute_component_name": "${project_component.name}",
        },
    },
}

config = config_reader.read(user_config)
pprint(config, sort_dicts=False)
objects = build_config(config["default"])
print("\n build objects: \n")
pprint(objects, sort_dicts=False)

print("\nmy_attribute_component_name:", objects["my_attribute_component_name"])

{'default': {'config_int': 1,
             'config_string': 'fire',
             'config_list': [1, 2, 3],
             'config_none': 'None',
             'config_dict': {'sub_config': 'water'},
             'project_component': {'*object': '__main__.ProjectComponent',
                                   'name': 'my_project_component'},
             'project': {'*object': '__main__.MyProject',
                         'project_component': '${project_component}'},
             'my_attribute_component': '${project_component}',
             'my_attribute_component_name': '${project_component.name}'}}

 build objects: 

{'config_int': 1,
 'config_string': 'fire',
 'config_list': [1, 2, 3],
 'config_none': None,
 'config_dict': {'sub_config': 'water'},
 'project_component': <__main__.ProjectComponent object at 0x7f1dc830c790>,
 'project': <__main__.MyProject object at 0x7f1dc830c6d0>,
 'my_attribute_component': <__main__.ProjectComponent object at 0x7f1dc830c790>,
 'my_attribute_component_name': 'my_project_component'}

my_attribute_component_name: my_project_component