Including an external library in a Docker/CMake Project - docker

Question

I am working on a cxx project using docker and cmake to build and I'm now tasked to integrate a third party library that I have locally.
To get started I added a project containing only a src folder and a single cpp file with a main function as well as includes that I will need from the library mentioned above. At this point, I'm already stuck as my included files are not found when I build in the docker environment. When I call cmake without docker on the project then I do not get the include error.
My directory tree:
my_new_project
CMakeLists.txt
src
my_new_project.cpp
In the CMakeLists.txt I've the following content:
CMAKE_MINIMUM_REQUIRED (VERSION 3.6)
project(my_new_project CXX)
file(GLOB SRC_FILES src/*.cpp)
add_executable(${PROJECT_NAME} ${SRC_FILES})
include_directories(/home/me/third_party_lib/include)
What is needed to make this build in the Docker environment? Would I need to convert the third party library into another project and add it as dependency (similar to what I do with projects from GitHub)?
I would be glad for any pointers into the right direction!
Edit:
I've copied the entire third party project root and can now get add include directories with include_directories(/work/third_party_lib/include), but would that be the way to go?

Answer 1

When you are building a new dockerized app, you need to COPY/ADD all your src, build and cmake files and define RUN instructions in your Dockerfile. This will be used to build your docker image that captures all the necessary binaries, resources, dependencies, etc.. Once the image is built, you can run the container from that image on docker, which can expose ports, bind volumes, devices, etc for your application.
So essentially, create your Dockerfile:
# Get the GCC preinstalled image from Docker Hub
FROM gcc:4.9
# Copy the source files under /usr/src
COPY ./src/my_new_project /usr/src/my_new_project
# Copy any other extra libraries or dependencies from your machine into the image
COPY /home/me/third_party_lib/include /src/third_party_lib/include
# Specify the working directory in the image
WORKDIR /usr/src/
# Run your cmake instruction you would run
RUN cmake -DKRISLIBRARY_INCLUDE_DIR=/usr/src/third_party_lib/include -DKRISLIBRARY_LIBRARY=/usr/src/third_party_lib/include ./ && \
make && \
make install
# OR Use GCC to compile the my_new_project source file
# RUN g++ -o my_new_project my_new_project.cpp
# Run the program output from the previous step
CMD ["./my_new_project"]
You can then do a docker build . -t my_new_project and then docker run my_new_project to try it out.
Also there are few great examples on building C** apps as docker containers:
VS Code tutorials: https://blogs.msdn.microsoft.com/vcblog/2018/08/14/c-development-with-docker-containers-in-visual-studio-code/
GCC image and sample: https://hub.docker.com/_/gcc/
For more info on the this, please refer to the docker docs:
https://docs.docker.com/engine/reference/builder/