Dockerfile does not work with docker version 24

[stefanhaerter]

Docker version 24.0.7, build 24.0.7-0ubuntu2~22.04.1

Apparently, this docker version does not like the HEREDOC syntax like here:

otobo/otobo.web.dockerfile

Lines 106 to 118 in 1663607

	RUN <<END_BASH bash
	set -eux
	PERL_CPANM_OPT="--local-lib /opt/otobo_install/local"
	cpanm --local-lib local Carton
	if [[ $DOCKER_TAG == local-* ]]
	then
	carton install
	else
	carton install --deployment
	fi
	rm -rf "/root/.cpanm"
	END_BASH

[bschmalhofer]

Changing the Dockerfiles to not using here documents is no problem. But I think that we should first discuss the required versions of Docker. We could also require different versions for running and for building Docker images.

[stefanhaerter]

According to some blog posts, heredoc support was added during 2021, which surprised me a bit because the docker version which I run seems to have been released in 2023. But I couldn't figure out which versions exactly have heredoc support.

[bschmalhofer]

Yes, this is a bit confusing. Another thing is that the builds on Docker Hub and GitHub are apparently building with buildkit. I think that the same should be done when building locally.
See https://docs.docker.com/build/buildkit/#getting-started . But still more confusion ensues. From reading the documentation I would have assumed that buildkit is used per default when running Docker 23 or later.

@stefanhaerter : Do you have special setup in your /etc/docker/daemon.json file ?

[stefanhaerter]

I have the folder /etc/docker on my system, but it is empty.