Some RUNs won't work on docker but will when inside a container - docker

Question

I've got a Dockerfile for some lua and torch related tasks and I'm trying to install some rocks using luarocks.
FROM ubuntu:14.04
RUN rm /bin/sh && ln -s /bin/bash /bin/sh
RUN apt-get update -y
RUN apt-get install -y curl git
RUN curl -s https://raw.githubusercontent.com/torch/ezinstall/master/install-deps | bash
RUN git clone https://github.com/torch/distro.git ~/torch --recursive
RUN cd ~/torch; ./install.sh
RUN source ~/.bashrc
RUN luarocks install nngraph
RUN luarocks install optim
RUN luarocks install nn
RUN luarocks install cltorch
RUN luarocks install clnn
docker build runs fine up until the first luarocks call: RUN luarocks install nngraph at which point it stops and throws the error:
/bin/sh: luarocks: command not found
If I comment out the luarocks lines, the build runs fine. Using that image, I can create a container and using bash, run luarocks as expected.
Of course, I don't particularly want to have to do this every time I start up the container, so I'm wondering if there's anything I can do to make this work. I have a feeling that this problem has something to do with the line RUN rm /bin/sh && ln -s /bin/bash /bin/sh but I need that to be able to run the line RUN source ~/.bashrc.
Thanks.

Answer 1

Each RUN command runs on its own shell and a new layer is committed.
From the Docker documentations:
RUN (the command is run in a shell - /bin/sh -c - shell
form)
So when you run luarocks install <app> it will not be the same shell you source your profile.
You have to provide the full path for luarocks to run. See below a modified Dockerfile I successfully run:
FROM ubuntu:14.04
RUN rm /bin/sh && ln -s /bin/bash /bin/sh
RUN apt-get update -y
RUN apt-get install -y curl git
RUN curl -s https://raw.githubusercontent.com/torch/ezinstall/master/install-deps | bash
RUN git clone https://github.com/torch/distro.git ~/torch --recursive
RUN cd ~/torch; ./install.sh
RUN source ~/.bashrc
RUN /root/torch/install/bin/luarocks install nngraph
RUN /root/torch/install/bin/luarocks install optim
RUN /root/torch/install/bin/luarocks install nn
RUN /root/torch/install/bin/luarocks install cltorch
RUN /root/torch/install/bin/luarocks install clnn
For more details see docker RUN documentation here.

Answer 2

As Alex da Silva pointed it out, sourcing .bashrc happens in another shell in your Dockerfile.
You could also try that to have your luarocks commands executed in the same shell with your sourced bashrc:
...
RUN source ~/.bashrc && luarocks install nngraph
RUN source ~/.bashrc && luarocks install optim
RUN source ~/.bashrc && luarocks install nn
RUN source ~/.bashrc && luarocks install cltorch
RUN source ~/.bashrc && luarocks install clnn