pip install fails if requirements.txt includes "-r path/to/more/requirements.txt"

[lbjay]

The requirements.txt in my app root only contains the line:

-r requirements/foo.txt

So the 'django:onbuild' image doesn't work for me because the Dockerfile only copies the requirements.txt file before running pip install. Could it not be simplified to just:

ONBUILD COPY . /usr/src/app
ONBUILD RUN pip install -r requirements.txt

[yosifkit]

The current ordering is to maximize docker caching. Doing a docker build, you don't want to have to wait for pip install every time that you change something in a python script.

This is the limitation of the onbuild images. They are meant for simple projects to just get you running. For more complicated setups (ie, that have multiple requirements files), we recommend just copying the items from the onbuild Dockerfile, removing ONBUILD from the commands, and then adding in your custom steps (like COPY requirements/foo.txt /usr/src/app/reqirements/foo.txt).

(related onbuild discussions: docker-library/ruby#35, docker-library/rails#28)

[lbjay]

Okey-doke. I'll carry on with my copied/modified Dockerfile. Thanks for the illumination.