Reloading packages (and their submodules) recursively in Python

Question

In Python you can reload a module as follows...

import foobar

import importlib
importlib.reload(foobar)

This works for .py files, but for Python packages it will only reload the package and not any of the nested sub-modules.

With a package:

• foobar/__init__.py
• foobar/spam.py
• foobar/eggs.py

Python Script:

import foobar

# assume `spam/__init__.py` is importing `.spam`
# so we dont need an explicit import.
print(foobar.spam)  # ok

import importlib
importlib.reload(foobar)
# foobar.spam WONT be reloaded.

Not to suggest this is a bug, but there are times its useful to reload a package and all its submodules. (If you want to edit a module while a script runs for example).

What are some good ways to recursively reload a package in Python?

Notes:

• For the purpose of this question assume the latest Python3.x

  (currently using importlib)

• Allowing that this may requre some edits to the modules themselves.
• Assume that wildcard imports aren't used (from foobar import *), since they may complicate reload logic.

Answer 1

Heres a function that recursively loads a package. Double checked that the reloaded modules are updated in the modules where they are used, and that issues with infinite recursion are checked for.

One restruction is it needs to run on a package (which only makes sense for packages anyway)

import os
import types
import importlib


def reload_package(package):
    assert(hasattr(package, "__package__"))
    fn = package.__file__
    fn_dir = os.path.dirname(fn) + os.sep
    module_visit = {fn}
    del fn

    def reload_recursive_ex(module):
        importlib.reload(module)

        for module_child in vars(module).values():
            if isinstance(module_child, types.ModuleType):
                fn_child = getattr(module_child, "__file__", None)
                if (fn_child is not None) and fn_child.startswith(fn_dir):
                    if fn_child not in module_visit:
                        # print("reloading:", fn_child, "from", module)
                        module_visit.add(fn_child)
                        reload_recursive_ex(module_child)

    return reload_recursive_ex(package)

# example use
import os
reload_package(os)