Need help snapping a python app

snapcraft
1

Hi,

I’m trying to snap my own local python package/app and run into some issues. Sample app is here: GitHub - juergh/testsnap

It’s a very simple classic snap that contains a python app that calls a system command (dput - another python program). The current state is that the execution of dput fails because it seems confused (see below) by PYTHONPATH which I had to set in snapcraft.yaml.

Questions/issues:

  1. Why do I have to manually stage the python interpreter? Shouldn’t snapcraft figure out by itself that it’s required?
  2. enable-patchelf seems necessary to prevent lint warnings. Do I really need this or am I doing something wrong?
  3. I need to set PYTHONPATH otherwise I’m getting the below, but PYTHONPATH breaks dput. It feels wrong to have to specify PYTHONPATH…
Traceback (most recent call last):
  File "/snap/testapp/x3/bin/testapp", line 5, in <module>
    from testapp.testapp import main
ModuleNotFoundError: No module named 'testapp'

Current output:

$ /snap/bin/testapp 
Calling dput...
Traceback (most recent call last):
  File "/usr/bin/dput", line 33, in <module>
    sys.exit(load_entry_point('dput==1.1.3+ubuntu3', 'console_scripts', 'execute-dput')())
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/bin/dput", line 25, in importlib_load_entry_point
    return next(matches).load()
           ^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/importlib/metadata/__init__.py", line 205, in load
    module = import_module(match.group('module'))
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/importlib/__init__.py", line 90, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 995, in exec_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/usr/share/dput/dput/dput.py", line 34, in <module>
    from .helper import dputhelper
  File "/usr/share/dput/dput/helper/dputhelper.py", line 17, in <module>
    import pkg_resources
  File "/snap/testapp/x6/lib/python3.10/site-packages/pkg_resources/__init__.py", line 2172, in <module>
    register_finder(pkgutil.ImpImporter, find_on_path)
                    ^^^^^^^^^^^^^^^^^^^
AttributeError: module 'pkgutil' has no attribute 'ImpImporter'. Did you mean: 'zipimporter'?

Any help is greatly appreciated. Thanks!

2

Add the path of test snap module to PYTHONPATH environment variable.

3

If the linter says so it is usually correct. The classic confinement snap runtime is different from the one in strict confinement so special care is needed.

1 Like
4

If the linter says so it is usually correct. The classic confinement snap runtime is different from the one in strict confinement so special care is needed.

Thanks for that clarification.

5

Add the path of test snap module to PYTHONPATH environment variable.

Which path is that? I’m not sure how this would unconfuse dput.

1 Like
6

Has the snap been published? Or somewhere available to look into?

7

The snap is here: Index of /~juergh/snap

This seems to be an unfortunate interaction of PYTHONPATH with the host’s Python version. 3.11 on the host works, 3.12 doesn’t. Googling reveals that Python 3.12 got rid of […the long-deprecated pkgutil.ImpImporter class…]. https://stackoverflow.com/questions/77364550/attributeerror-module-pkgutil-has-no-attribute-impimporter-did-you-mean

Which to me seems I need to get rid of PYTHONPATH somehow.

8

For the record, switching to base: core24 fixed the problem.

1 Like