As the title says. I need to be able to retrieve the IP address the docker hosts and the portmaps from the host to the container, and doing that inside of the container.
In linux you can run
HOST_IP=`hostname -I | awk '{print $1}'`
In macOS your host machine is not the Docker host. Docker will install it's host OS in VirtualBox.
HOST_IP=`docker run busybox ping -c 1 docker.for.mac.localhost | awk 'FNR==2 {print $4}' | sed s'/.$//'`