load_module for import entire package

[Sergey]

Hi,
I need to import package and instantiate a class, defined in one of modules, located in package.

Package is located in folder "tmp". basedir - path to running python script.

I'm doing it so:

import imp

def load_package_strict(p_package_name, p_package_path):
f, filename, description = imp.find_module(p_package_name, [p_package_path])
try:
result = imp.load_module(p_package_name, f, filename, description)
finally:
if f: f.close
return result

def get_obj():
pkg = load_package_strict("tmp", basedir)
from tmp import main
return main.TTT()

It is working, but if package code changes on disc at runtime and I call get_obj again, it returns instance of class, loaded for the first time previously.

How to replace line "from tmp import main" by getting properties of pkg?

Regards,
Sergey

 

[Dave Angel]

def get_obj():
pkg = load_package_strict("tmp", basedir)
from tmp import main
return main.TTT()

It is working, but if package code changes on disc at runtime and I

call get_obj again, it returns instance of class, loaded for the
first time previously.

That's how import works. Once something has been imported, the
module information is cached. There are three ways to defeat that,
but they're all risky.

How to replace line "from tmp import main" by getting properties of

pkg?

No clue what you mean by that.

 

[alex23]

def get_obj():
pkg = load_package_strict("tmp", basedir)
from tmp import main
return main.TTT()

It is working, but if package code changes on disc at runtime and I call get_obj again, it returns instance of class, loaded for the first time previously.

How to replace line "from tmp import main" by getting properties of pkg?

Your `load_package_strict` function loads the `tmp` module and binds it
to the name `pkg`. You then use a regular import to load `tmp.main`,
which is _cached_; all subsequent occurrences reuse the initially
imported value.

This should work:

def get_obj():
tmp = load_package_strict("tmp", basedir)
return tmp.main.TTT()

 

[Sergey]

This should work:

def get_obj():
tmp = load_package_strict("tmp", basedir)
return tmp.main.TTT()

Thank you
I can only mention that it is working only if __init__.py of pkg contains line: import main

To avoid modules caching I copy package to the new folder with another name and import it using this new name.

tmp_pkg = "t" + str(randint(10000,100000000)) + '_' + time.strftime("%Y%m%d%H%M%S", time.localtime())
shutil.copytree(pkg_dir, basedir + '/x/' + dir_name + '/' + tmp_pkg)

pkg = load_package_strict(tmp_pkg, basedir + '/x/' + dir_name)
result = pkg.main.TTT()
What is the risk of this method? What are 3 methods of doing the same?