Create a Docker image via CMake

This project creates a docker image using CMake. The image holds an executable that was also built by the same CMake build system. It correctly models various file dependencies so that only out-of-date items are rebuilt.

Here's the utilitarian user's guide:

# Clone and build.
mkdir build
cd build
cmake ..
make

# Run the docker image that was just built.
docker run --rm cmake-docker-example

# Run make again. Nothing should be rebuilt.
make

# Touch the main.c file, then run make again.
# Notice how both the executable and the dockerfile
# are rebuilt.
touch ../main.c
make

Best Good practices

This project follows good practices by correctly modeling the various dependencies between the docker image and its source files (i.e. the executable target and Dockerfile).

Bad practices

This project yanks an executable out of the build tree and dumps it into a Docker image. The executable has the wrong RPATH and may not be setup for the image's operating system (e.g. building on Ubuntu but creating a CentOS image).

A better option would be to use CPack to create a "shippable" binary, then inject that package into the image. I've had good success doing this with TGZs and RPMs. Maybe someday I'll extend this example to demonstrate that...