Dfyjkt

I'm runnin Python 3.6.3 and I have the following module in a subdirectory that I'm trying to install through pip.

/g_plotter
 setup.py
 /g_plotter
 __init__.py
 g_plotter.py
 Gparser.py

setup.py

from setuptools import setup

setup(
 name='g_plotter',
 packages=['g_plotter'],
 include_package_data=True,
 install_requires=[
 'flask',
 ],
)

I installed that module form Docker in my container:

RUN pip3 install ./g_plotter

Then in my app code:

import g_plotter

print(dir(g_plotter))

which outputs

 server_1 | ['__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__path__', '__spec__']

so using this import instead:

from g_plotter import g_plotter

results in

server_1 | Traceback (most recent call last):
server_1 | File "./g_server.py", line 21, in <module>
server_1 | from g_plotter import g_plotter
server_1 | File "/usr/local/lib/python3.7/site-packages/g_plotter/g_plotter.py", line 7, in <module>
server_1 | import Gparser
server_1 | ModuleNotFoundError: No module named 'Gparser'

When I run the submodule on it's own (It's a flask app), it works.

You must use absolute import in python 3, import Gparser is not allowed any more. You can change it to:

from . import Gparser
from g_plotter import Gparser

Let you more clear, I will describe what do they mean.

import Gparser

Gparser = load_module()
sys.modules['Gparser'] = Gparser

from g_plotter import Gparser

Gparser = load_module()
sys.modules[Gparser_name] = Gparser

from . import Gparser

package = find_package(__name__) # 'g_plotter'
Gparser_name = package + 'Gparser' # g_plotter.Gparser
Gparser = load_module()
sys.modules[Gparser_name] = Gparser

Now you can understand, if you run g_plotter directly, actually __name__ is __main__, so python can't find a package from it. Only if you import this submodule in other module, from . import something can be worked.