Example of declaring and loading namespace packages

load.py

# dirs/c/xx_plugins/c_module/__init__.py
# dirs/c/xx_plugins/d_module/__init__.py
# dirs/a/b/xx_plugins/ab_module/__init__.py
import sys
import os.path as op
import importlib
import pkgutil
from types import ModuleType
from typing import List

def _import_namespace(namespace: str):

  ns = importlib.import_module(namespace)
  if not hasattr(ns, '__path__') and getattr(ns, '__file__', None):
    raise TypeError(f'module {namespace} is not a namespace module')

  modules = []
  for spec in pkgutil.iter_modules(ns.__path__):
    fqn = '.'.join([namespace, spec.name])
    loader = pkgutil.get_loader(fqn)
    module = loader.load_module(fqn)
    modules.append(module)

  return ns, modules

def import_namespace_modules(namespace: str, module_dirs: List[str]):

  module_dirs = list(map(op.abspath, module_dirs))
  for path in module_dirs:
    sys.path.insert(0, path)

  try:
    return _import_namespace(namespace)
  except:
    raise
  finally:
    for path in module_dirs:
      if path in sys.path:
        sys.path.remove(path)

  return None, None

module_paths = ['dirs/a/b', 'dirs/c']
ns, modules = import_namespace_modules('xx_plugins', module_paths)

from xx_plugins import d_module
print(d_module)

ns_modules.tar

dirs/c/xx_plugins/c_module/__init__.py0000664000175000017500000000007614060254606020301 0ustar  mcuttermcutter

print('C imported')


def c_func():
  print('C func called')dirs/c/xx_plugins/d_module/__init__.py0000664000175000017500000000011514060254565020300 0ustar  mcuttermcutter

print('D module loaded')

from xx_plugins.c_module import c_func

c_func()
dirs/a/b/xx_plugins/ab_module/__init__.py0000664000175000017500000000002614060251722020647 0ustar  mcuttermcutter

print('AB imported')