Docker file for building code cloned from git - github

Question

I've cloned a copy of FreeCAD from github and I'm trying to create a docker file so that I can develop it locally on my machine.
The objectives being that:
I have a local copy of the code from git on my machine
I can make modifications to the code
I can build debug and release image (do I need to create two separate images?)
Have access to the code on my machine, so that I can use git for source control
This is the content of my Dockerfile:
# Get base image
FROM phusion/baseimage
# Use baseimage-docker's init system.
CMD ["/sbin/my_init"]
# Get the build pre-requisites
RUN apt-get update
RUN apt-get install -y build-essential cmake python python-matplotlib libtool
RUN apt-get install -y libcoin80-dev libsoqt4-dev
RUN apt-get install -y libxerces-c-dev libboost-dev libboost-filesystem-dev
RUN apt-get install -y libboost-regex-dev
RUN apt-get install -y libboost-program-options-dev libboost-signals-dev
RUN apt-get install -y libboost-thread-dev libboost-python-dev libqt4-dev
RUN apt-get install -y libqt4-opengl-dev qt4-dev-tools python-dev
RUN apt-get install -y python-pyside pyside-tools
RUN apt-get install -y liboce*-dev oce-draw
RUN apt-get install -y libeigen3-dev libqtwebkit-dev libshiboken-dev
RUN apt-get install -y libpyside-dev libode-dev swig libzipios++-dev
RUN apt-get install -y libfreetype6 libfreetype6-dev
# to make Coin to support additional image file formats
RUN apt-get install -y libsimage-dev
# to register your installed files into your system's package manager, so yo can easily uninstall later
RUN apt-get install -y checkinstall
# needed for the 2D Drafting module
RUN apt-get install -y python-qt4 python-pivy
# doxygen and libcoin80-doc (if you intend to generate source code documentation)
RUN apt-get install -y doxygen libcoin80-doc
# libspnav-dev (for 3Dconnexion devices support like the Space Navigator or Space Pilot)
RUN apt-get install -y libspnav-dev
# CMAke related issue for compiling on Ubuntu Xenial: http://forum.freecadweb.org/viewtopic.php?f=4&t=16292
RUN apt-get install -y libmedc-dev
RUN apt-get install -y libvtk6-dev
RUN apt-get install -y libproj-dev
# Get git
RUN apt-get install -y git
RUN git clone https://github.com/FreeCAD/FreeCAD.git freecad
RUN cd freecad
RUN mkdir freecad-debug
RUN cd freecad-debug
# command below is just a diagnostic to let me know wth I am (output is: /)
# RUN pwd
RUN cmake ../ -DFREECAD_USE_EXTERNAL_PIVY=1 -DCMAKE_BUILD_TYPE=Debug .
#cmake -DFREECAD_USE_EXTERNAL_PIVY=1 -DCMAKE_BUILD_TYPE=Release .
RUN make
I attempt to build the image using the following command:
docker build -tag freeCAD-my-fork .
Everything works until I get to the first cmake invocation. I then get the following error:
CMake Error: The source directory "/" does not appear to contain CMakeLists.txt.
Specify --help for usage, or press the help button on the CMake GUI.
The command '/bin/sh -c cmake ../ -DFREECAD_USE_EXTERNAL_PIVY=1 -DCMAKE_BUILD_TYPE=Debug .' returned a non-zero code: 1
I placed a RUN pwd in my Dockerfile, so I could find where the cmake command was being run from, and I was surprised to find that it was been run from the root directory.
I thought the issue was being caused by my use of relative and that it would be fixed by absolute paths - however specifying /path/to/my/copy/freecad when cloning etc, the issue remains.
How can I write my Dockerfile so that it achieves the objectives outlined above (stated at the beginning of my question)?

Answer 1

Default WORKDIR in docker is "/".All docker commands will be executed in that directory.There are two option either you change WORKDIR(https://docs.docker.com/engine/reference/builder/#workdir) or execute everything in one layer(In one RUN command).I have taken second approach.
Cloning and Building source code both executed in One layer of docker.
RUN git clone https://github.com/FreeCAD/FreeCAD.git freecad \
&& cd freecad \
&& mkdir freecad-debug \
&& cd freecad-debug \
&& cmake ../ -DFREECAD_USE_EXTERNAL_PIVY=1 -DCMAKE_BUILD_TYPE=Debug . \
&& make

Answer 2

You should install all your dependencies using run as you do but the actual building and copying of source code files should not happen when you build your image but when you run a container.
This way you can reuse your image for as many builds as you like.
Write a script with the build commands and copy it over to your image. Then in the CMD part of the dockerfile run that script.
To share the git project with the container you can mount your local files with docker run -v hostpath:containerpath imagename. That way any files in hostpath will be visible to the container at containerpath and vice versa. Alternatively you could also git clone from the script which is invoked by CMD but then you have to expose the build somehow to your host (some mounted volume again).