Minimal example driving Python importlib machinery to import a runtime created module

importlib_importer_poc.py

#!/usr/bin/env python3

import importlib.machinery
import sys
import types


class Finder:
    def find_spec(self, fullname, path, target=None):
        if fullname != 'poc_module':
            return None

        spec = importlib.machinery.ModuleSpec(
            fullname,
            loader=Loader(),
            origin='<fevered imagination>',
        )
        return spec


class Loader:
    def create_module(self, spec):
        module = types.ModuleType(spec.name)
        module.__spec__ = spec
        module.__loader__ = spec.loader
        module.__file__ = spec.origin
        return module

    def exec_module(self, module):
        source = 'import math; tau=2*math.pi; print("Hello importlib fans!")'
        code = compile(source, module.__file__, 'exec')
        exec(code, module.__dict__)


print('Inserting Finder into meta_path')
sys.meta_path.insert(0, Finder())

print('Importing poc_module')
import poc_module

print(f'{poc_module=}')
print(f'{poc_module.__spec__=}')
print(f'{poc_module.tau=}')

This Proof of Concept demonstrates a dynamically generated Python module getting imported. There is no poc_module.py on disk.

$ python3 importlib_importer_poc.py
Inserting Finder into meta_path
Importing poc_module
Hello importlib fans!
poc_module=<module 'poc_module' (<fevered imagination>)>
poc_module.__spec__=ModuleSpec(name='poc_module', loader=<__main__.Loader object at 0x1046219d0>, origin='<fevered imagination>')
poc_module.tau=6.283185307179586

The Python import machinery is (somewhat) described in https://docs.python.org/3/reference/import.html and https://docs.python.org/3/library/importlib.html