Add containerfile element

This is a base element which uses a containerfile (Dockerfile) to
build a container image, then the filesystem is extracted from that
image and forms the root of the dib image.

You can add as little or as much to the dockerfile as desired.

Change-Id: I4e821aa2ce7feb8841ef31da56de1a31aa9218b5

.zuul.d/jobs.yaml

@@ -29,6 +29,7 @@
         - ubuntu-minimal/xenial-build-succeeds
         - ubuntu-minimal/bionic-build-succeeds
         - ubuntu-minimal/focal-build-succeeds
+        - containerfile/focal-build-succeeds
 
 - job:
     name: dib-functests-image

diskimage_builder/elements/containerfile/README.rst

@@ -0,0 +1,9 @@
+=============
+containerfile
+=============
+
+Base element for creating images from container files (aka
+Dockerfiles).
+
+To use this element, create a container file (Dockerfile), and supply
+the path to that file in the environment variable `DIB_CONTAINER_FILE`.

diskimage_builder/elements/containerfile/element-provides

@@ -0,0 +1 @@
+operating-system

diskimage_builder/elements/containerfile/root.d/08-containerfile

@@ -0,0 +1,42 @@
+#!/bin/bash
+#
+# Copyright 2015 Hewlett-Packard Development Company, L.P.
+# Copyright 2019 Red Hat, INC.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+if [ ${DIB_DEBUG_TRACE:-1} -gt 0 ]; then
+    set -x
+fi
+set -eu
+set -o pipefail
+
+if [ -f ${TARGET_ROOT}/.extra_settings ] ; then
+    . ${TARGET_ROOT}/.extra_settings
+fi
+
+[ -n "$DIB_CONTAINER_FILE" ]
+
+# Use the image cache directory as the default context, so anything
+# there is automatically available for COPY commands.
+DIB_CONTAINER_CONTEXT=${DIB_CONTAINER_CONTEXT:-${DIB_IMAGE_CACHE}/containerfile}
+
+mkdir -p $DIB_CONTAINER_CONTEXT
+
+podman build -t dib-work-image -f $DIB_CONTAINER_FILE $DIB_CONTAINER_CONTEXT
+container=$(podman run -d dib-work-image /bin/sh)
+podman export $container | sudo tar -C $TARGET_ROOT --numeric-owner -xf -
+podman rm $container
+podman rmi dib-work-image
+
+sudo rm -f ${TARGET_ROOT}/.extra_settings

diskimage_builder/elements/containerfile/test-elements/focal-build-succeeds/README.rst

@@ -0,0 +1,2 @@
+Verify we can build an image from a containerfile.
+

diskimage_builder/elements/containerfile/test-elements/focal-build-succeeds/element-deps

@@ -0,0 +1 @@
+openstack-ci-mirrors

diskimage_builder/elements/containerfile/test-elements/focal-build-succeeds/environment.d/10-set-distro.bash

@@ -0,0 +1,2 @@
+# For the openstack-ci-mirrors element
+export DISTRO_NAME=ubuntu

diskimage_builder/elements/containerfile/test-elements/focal-build-succeeds/environment.d/10-set-file.bash

@@ -0,0 +1,3 @@
+path="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+path="$( dirname $path)"
+export DIB_CONTAINER_FILE="$path/files/Dockerfile"

diskimage_builder/elements/containerfile/test-elements/focal-build-succeeds/files/Dockerfile

@@ -0,0 +1,2 @@
+FROM docker.io/library/ubuntu:focal
+RUN touch /testfile

diskimage_builder/elements/containerfile/test-elements/focal-build-succeeds/test-output-formats

@@ -0,0 +1 @@
+tar

playbooks/dib-functests/run.yaml

@@ -4,5 +4,6 @@
     - ensure-pip
     - bindep
     - dib-setup-gate-mirrors
+    - ensure-podman
     - dib-functests