Add a Dockerfile.buildroot

Dockerfile.buildroot

@@ -0,0 +1,15 @@
+# This layers on top of the primary cosa container, and includes
+# the build dependencies for some key packages such as
+# ignition, rpm-ostree, libpod, systemd, and kernel.  If you want
+# another package in this list, submit a PR and we can probably add it.
+#
+# Further, the entrypoint is reset to bash, and the user to root, making
+# this container easier to use generically.  For example, the rpm-ostree
+# CI system will likely use this as a base image.
+FROM quay.io/coreos-assembler/coreos-assembler:latest
+USER root
+ENTRYPOINT ["/usr/bin/bash"]
+WORKDIR /root/containerbuild
+COPY src src
+RUN ./src/install-buildroot.sh && yum clean all && rm src -rf
+WORKDIR /root

src/buildroot-buildreqs.txt

@@ -0,0 +1,9 @@
+# This is what the CoreOS developers tend to actively develop/own.
+# If you want to extend this, feel free to file a PR.
+ignition
+ostree
+rpm-ostree
+kernel
+systemd
+dracut
+podman

src/buildroot-reqs.txt

@@ -0,0 +1,29 @@
+# This is a list of basic buildrequires; it'd be a bit better to
+# yum -y install @buildsys-build but unfortunately that hits a bug:
+# https://fedoraproject.org/wiki/Common_F30_bugs#Conflicts_between_fedora-release_packages_when_installing_package_groups
+# So here we inline it, minus the -release package.
+bash
+bzip2
+coreutils
+cpio
+diffutils
+findutils
+gawk
+glibc-minimal-langpack
+grep
+gzip
+info
+make
+patch
+redhat-rpm-config
+rpm-build
+sed
+shadow-utils
+tar
+unzip
+util-linux
+which
+xz
+
+# Also, add clang since it's useful at least in CI for C/C++ projects
+clang

src/install-buildroot.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+# This is invoked by Dockerfile.buildroot
+set -euo pipefail
+dn=$(dirname "$0")
+deps=$(grep -v '^#' "${dn}"/buildroot-reqs.txt)
+echo "Installing requirements"
+echo "${deps}" | xargs yum -y install
+brs=$(grep -v '^#' "${dn}"/buildroot-buildreqs.txt)
+echo "Installing build dependencies of primary packages"
+echo "${brs}" | xargs yum -y builddep
+echo 'Done!'