How to install local packages using pip as part of a docker build?

Question

I've got a package that I want to build into a docker image which depends on an adjacent package on my system.

My requirements.txt looks something like this:

 -e ../other_module numpy==1.0.0 flask==0.12.5 

When I call pip install -r requirements.txt in a virtualenv this works fine. However, if I call this in a Dockerfile, e.g.:

 ADD requirements.txt /app RUN pip install -r requirements.txt 

and run using docker build . I get an error saying the following:

../other_module should either be a path to a local project or a VCS url beginning with svn+, git+, hg+, or bzr+

What, if anything, am I doing wrong here?

Answer 1

First of all, you need to add other_module to your Docker image. Without that, the pip install command will not be able to find it. However you cant ADD a directory that is outside the directory of the Dockerfile according to the documentation:

The path must be inside the context of the build; you cannot ADD ../something /something, because the first step of a docker build is to send the context directory (and subdirectories) to the docker daemon.

So you have to move the other_module directory into the same directory as your Dockerfile, i.e. your structure should look something like

. ├── Dockerfile ├── requirements.txt ├── other_module |   ├── modue_file.xyz |   └── another_module_file.xyz 

then add the following to the dockerfile:

ADD /other_module /other_module ADD requirements.txt /app WORKDIR /app RUN pip install -r requirements.txt 

The WORKDIR command moves you into /app so the next step, RUN pip install... will be executed inside the /app directory. And from the app-directory, you now have the directory../other_module avaliable