coed

Configurable Object Entry-point Discovery.

Installation

Install via pip:

pip install "git+https://github.com/waikato-datamining/coed.git"

Usage

Approach:

1. define a class lister function
2. reference the class lister function in setup.py
3. create a custom registry
4. query classes

For the examples below, we assume that the project is called project42.

Class lister function

The class lister function simply returns a dictionary of super classes associated with lists of packages that classes derived from these super classes may occur in.

For example, the following function is located in module project42.class_lister:

from typing import List, Dict

def list_classes() -> Dict[str, List[str]]:
    return {
        "project42.superclass.One": [
            "project42.one",
            "project42.two",
        ],
        "project42.superclass.Two": [
            "project42.deep.deeper.deepest.another",
        ],
        "project42.superclass.Three": [
            "project42.one",
            "project42.three",
            "project42.deep.four",
            "project42.five",
        ],
    }

Entry point in setup.py

The format for referencing the class lister function is as follows:

    ...
    entry_points={
        "class_lister": [
            "unique_name=module_name:function_name",
        ],
    },
    ...

If the function_name is list_classes, it can be omitted.

The above example class lister function would be referenced like this:

    ...
    entry_points={
        "class_lister": [
            "project42=project42.class_lister",
        ],
    },
    ...

Custom registry

Create a custom registry (module project42.registry):

from coed.registry import Registry as CRegistry

ENV_CLASSLISTERS = "PROJECT42_CLASSLISTERS"

class Registry(CRegistry):
    """
    Registry for managing plugins.
    """

    def __init__(self):
        super().__init__(env_class_listers=ENV_CLASSLISTERS)


REGISTRY = Registry()

Notes The environment variable is useful while developing, as the entrypoints are only available when installing the library.

While developing in your IDE, you can set the PROJECT42_CLASSLISTERS environment variable to list all your class lister functions (comma-separated list), e.g.:

PROJECT42_CLASSLISTERS=project42.class_lister:list_classes

Query classes

With the registry in place, you can now obtain all the classes that have been associated with a certain super class, e.g.:

from project42.registry import REGISTRY

classes = REGISTRY.classes("project42.superclass.One")
for c in classes:
    print(c)