Dockerfile CMD脚本的运行方式与在容器中手动运行的脚本不同

Question

I have a dockerfile with the following end

CMD python app/start.py arg1 arg2 arg3

And when I try calling run (through compose) it gives me an error from my python script:

Traceback (most recent call last):
  File "app/start.py", line 4, in <module>
    from utils.foo import bar
ImportError: No module named 'utils'

However, when I call run ... bash (again through compose) or set the compose command argument to bash , and then in the bash terminal that comes up run:

python app/start.py arg1 arg2 arg3

The script runs perfectly.

I assume this is something to do with how folder structure is handled on startup. Is there something I don't understand about how CMD works in dockerfiles?

Updates

• Running with ENTRYPOINT instead of CMD makes no difference
• Setting CMD to bash -c "python app/start.py arg1 arg2 arg3" makes no difference

Answer 1

This is definitely not the best solution, but it ended up working for me.

I simply created a new top level file start.py with:

from app.start import startup

startup()

And replaced the command:

CMD python start.py arg1, arg2, arg3

And it worked fine. I feel this somewhat confirms my suspicion that it was something to do with the file hierarchy, but as to why this occurs only when running off CMD still has me stumped. Any suggestions for a better solution would be much appreciated.