Build a Linux C++ Project in a Docker Container without contaminating your system with unnecessary development files.

Building C++ Projects in Docker.

Building C++ projects in Linux can be a pain, especially if the project maintainer does not have a good build process. Many projects need you to install dependencies. Sometimes they even give you a bootstrap.sh script which runs sudo commands to install packages. I personally hate when scripts attempt to install packages, add things to my bashrc file, modify my PATH or any of the sort.

To protect from these things, we’d like to create an isolated environment where you can build the project and pass the build objects back to your host system without contaminating your host with unnecessary development files.

I have created a few docker images which contain a lot of the required build essentials, plus a few extra libraries that are common. Such as Qt, CMake Conan, Ninja, etc. They are based off the ConanCenter docker images ( https://github.com/conan-io/conan-docker-tools )

The images come with the following packages:

gcc
Cmake, Ninja, Conan Package Manager
Qt Development files
OpenGL
Vulkan (ubuntu 20.04 version only)
Various other libraries

Here’s a quick set of commands to build the images.


cd /tmp

git clone https://github.com/GavinNL/gcc-dockerfiles

cd gcc-dockerfiles

cd bionic-gcc7
docker build -t ubuntu1804gcc:Dockerfile .

cd ../focal-gcc9
docker build -t ubuntu2004gcc:Dockerfile .

cd /tmp

rm -rf gcc-dockerfiles

There are two images, One based off Ubuntu 18.04 and the other based off Ubuntu 20.04.

The Docker Command

To use these images, simply create an empty folder where you’d like to build your project and then execute the docker command. This will create two mounted folders in the image, one for the build files and one for the source. The source folder is mounted as read-only using the :ro tag, but if you don’t need this, you can remove it.


mkdir build

docker run --rm --it PATH_TO_BUILD_FOLDER:/conan/build PATH_TO_SOURCE:/conan/src:ro ubuntu2004gcc:Dockerfile /bin/bash

Bash Functions

I have the following two bash functions in my $HOME/.bashrc file. I can now quickly choose which Ubuntu platform I want to build for.


# Start a gcc7 environment using Ubuntu 18.04 to build a C++ project  
#
# mkdir path/to/empty/build
# gcc7 /path/to/source/folder
#
gcc7() {
    echo "Using $PWD as Build folder"
    if [[ "$1" == "" ]]; then
        echo "Argument 1 Needs to be the project folder"
        return 1
    fi

    docker run --rm -it -v ${PWD}:/home/conan/build -v $(realpath ${1}):/home/conan/src:ro ubuntu1804gcc:Dockerfile /bin/bash
}

# Start a gcc9 environment using Ubuntu 20.04 to build a C++ project  
#
# mkdir path/to/empty/build
# gcc9 /path/to/source/folder
#
gcc9() {
    echo "Using $PWD as Build folder"
    if [[ "$1" == "" ]]; then
        echo "Argument 1 Needs to be the project folder"
        return 1
    fi

    docker run --rm -it -v ${PWD}:/home/conan/build -v $(realpath ${1}):/home/conan/src:ro ubuntu2004gcc10:Dockerfile /bin/bash
}

Example

We are going to build the Easy Profiler GUI on Ubuntu 20.04


git clone https://github.com/yse/easy_profiler

cd easy_profiler

mkdir build
cd build

gcc9 ..

# we are now in the docker container

cd build
cmake ../src -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=Off

make

#exit the container
exit

If everything worked out, you should have the executable binaries in the build folder on your host. Because the container used the same Ubuntu image, it should be able to find the Qt libraries on your system.

Building Linux C++ Projects in Docker

Building C++ Projects in Docker.

The Docker Command

Bash Functions

Example