github.com/containers/podman/v5@v5.1.0-rc1/test/system/build-testimage

#!/bin/bash
#
# build-testimage - script for producing a test image for podman CI
#
# The idea is to have a small multi-purpose image that can be pulled once
# by system tests and used for as many tests as possible. This image
# should live on quay.io, should be small in size, and should include
# as many components as needed by system tests so they don't have to
# pull other images.
#
# Unfortunately, "small" is incompatible with "systemd" so tests
# still need a fedora image for that.
#

# Podman binary to use
PODMAN=${PODMAN:-$(pwd)/bin/podman}

# Tag for this new image
YMD=$(date +%Y%m%d)

# git-relative path to this script
create_script=$(cd $(dirname $0) && git ls-files --full-name $(basename $0))
if [ -z "$create_script" ]; then
    create_script=$0
fi

# Creation timestamp, Zulu time
create_time_t=$(date +%s)
create_time_z=$(env TZ=UTC date --date=@$create_time_t +'%Y-%m-%dT%H:%M:%SZ')

set -ex

# We'll need to create a Containerfile plus various other files to add in
#
# Please document the reason for all flags, apk's, and anything non-obvious
tmpdir=$(mktemp -t -d $(basename $0).tmp.XXXXXXX)
cd $tmpdir

# 'image mount' test will confirm that this file exists and has our YMD tag
echo $YMD >testimage-id

# ...but set the timestamp on the file itself to a constant well-known
# value, for use by the 'run --tz' test. Date value chosen for nerdiness
# and because it's in the past. (Much as I'd love FFFFFFFF, we can't
# use any future date because of unpredictable leap second adjustments).
touch --date=@1600000000 testimage-id

# 'pod' test will use this for --infra-command
cat >pause <<EOF
#!/bin/sh
#
# Trivial little pause script, used in one of the pod tests
#
trap 'exit 0' SIGTERM
echo Confirmed: testimage pause invoked as \$0
while :; do
    sleep 0.1
done
EOF
chmod 755 pause

# Add a health check
cat >healthcheck <<EOF
#!/bin/sh

if test -e /uh-oh || test -e /uh-oh-only-once; then
    echo "Uh-oh on stdout!"
    echo "Uh-oh on stderr!" >&2

    # Special file causes us to fail healthcheck only once
    rm -f /uh-oh-only-once

    exit 1
else
    echo "Life is Good on stdout"
    echo "Life is Good on stderr" >&2
    exit 0
fi
EOF
chmod 755 healthcheck

# alpine because it's small and light and reliable
#    - check for updates @ https://hub.docker.com/_/alpine
# busybox-extras provides httpd needed in 500-networking.bats
# iproute2 provides JSON output (not in busybox) for 505-networking-pasta.bats
# socat offers convenient UDP test termination in 505-networking-pasta.bats
#
# Two Containerfiles, because we have to do the image build in two parts,
# which I think are easier to describe in reverse order:
#    2) The second build has to be run with --timestamp=CONSTANT, otherwise
#       the Created test in 110-history.bats may fail (#14456); but
#    1) the timestamp of the testimage-id file must be preserved (see above),
#       and 'build --timestamp' clobbers all file timestamps.
#
cat >Containerfile1 <<EOF
ARG REPO=please-override-repo
FROM docker.io/\${REPO}/alpine:3.19.0
RUN apk add busybox-extras iproute2 socat
ADD testimage-id healthcheck pause /home/podman/
RUN rm -f /var/cache/apk/*
EOF

cat >Containerfile2 <<EOF
FROM localhost/interim-image:latest
LABEL created_by=$create_script
LABEL created_at=$create_time_z
WORKDIR /home/podman
CMD ["/bin/echo", "This container is intended for podman CI testing"]
EOF

# Start from scratch
testimg_base=quay.io/libpod/testimage
testimg=${testimg_base}:$YMD
$PODMAN rmi -f $testimg &> /dev/null || true

# There should always be a testimage tagged ':0000000<X>' (eight digits,
# zero-padded sequence ID) in the same location; this is used by tests
# which need to pull a non-locally-cached image. This image will rarely
# if ever need to change, nor in fact does it even have to be a copy of
# this testimage since all we use it for is 'true'.
# However, it does need to be multiarch :-(
zerotag_latest=$(skopeo list-tags docker://${testimg_base} |\
                     jq -r '.Tags[]' |\
                     sort --version-sort |\
                     grep '^000' |\
                     tail -n 1)
zerotag_next=$(printf "%08d" $((zerotag_latest + 1)))

# We don't always need to push the :00xx image, but build it anyway.
zeroimg=${testimg_base}:${zerotag_next}
$PODMAN manifest create $zeroimg

# Arch emulation on Fedora requires the qemu-user-static package.
for arch in amd64 arm64 ppc64le s390x;do
    # docker.io repo is usually the same name as the desired arch; except
    # for arm64, where podman needs to have the arch be 'arm64' but the
    # image lives in 'arm64v8'.
    repo=$arch
    if [[ $repo = "arm64" ]]; then
        repo="${repo}v8"
    fi

    # First build defines REPO, but does not have --timestamp
    $PODMAN build \
            --arch=$arch \
            --build-arg REPO=$repo \
            --squash-all \
            --file Containerfile1 \
            -t interim-image \
            .

    # Second build forces --timestamp, and adds to manifest. Unfortunately
    # we can't use --squash-all with --timestamp: *all* timestamps get
    # clobbered. This is not fixable (#14536).
    $PODMAN build \
            --arch=$arch \
            --timestamp=$create_time_t \
            --manifest=$testimg \
            --squash \
            --file Containerfile2 \
            .

    # No longer need the interim image
    $PODMAN rmi interim-image

    # The zero-tag image
    $PODMAN pull --arch $arch     docker.io/$repo/busybox:1.34.1
    $PODMAN manifest add $zeroimg docker.io/$repo/busybox:1.34.1
done

# Clean up
cd /tmp
rm -rf $tmpdir

# Tag image and push (all arches) to quay.
cat <<EOF

If you're happy with these images, run:

   podman manifest push --all  ${testimg} docker://${testimg}
   podman manifest push --all  ${zeroimg} docker://${zeroimg}

(You do not always need to push the :0000 image)

EOF