How do you add a path to PYTHONPATH in a Dockerfile
PythonDockerPathPython Problem Overview
How do you add a path to PYTHONPATH in a Dockerfile? So that when the container is run it has the correct PYTHONPATH? I'm completely new to Docker.
I've added ENV PYTHONPATH "${PYTHONPATH}:/control" to the Dockerfile as I want to add the directory /control to PYTHONPATH.
When I access the container's bash with docker exec -it trusting_spence bash and open python and run the commands below the directory control is not on the list.
import sys print(sys.path)
FROM python:2
RUN pip install requests pymongo
RUN mkdir control
COPY control_file/ /control
ENV PYTHONPATH "${PYTHONPATH}:/control"
CMD ["python","control/control_file/job.py"]
Python Solutions
Solution 1 - Python
Just add an ENV entry in your Dockerfile:
ENV PYTHONPATH "${PYTHONPATH}:/your/custom/path"
Or set PYTHONPATH in your startup script.
Solution 2 - Python
You're setting the python path correctly, but your command is not being run by a shell, so the environment variable PYTHONPATH is not considered.
chang your CMD from "exec" form to "shell" form:
CMD python control/control_file/job.py
From the Docs:
> Note: Unlike the shell form, the exec form does not invoke a command shell. This means that normal shell processing does not happen. For example, CMD [ "echo", "$HOME" ] will not do variable substitution on $HOME. If you want shell processing then either use the shell form or execute a shell directly, for example: CMD [ "sh", "-c", "echo $HOME" ]. When using the exec form and executing a shell directly, as in the case for the shell form, it is the shell that is doing the environment variable expansion, not docker.
Solution 3 - Python
Do it in a much simpler way. Add the python path in your .env file as a line in this way.
PYTHONPATH=/app/project_source/