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.
#

# Buildah binary
BUILDAH=${BUILDAH:-buildah}

# 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_z=$(env TZ=UTC date +'%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
#
echo Confirmed: testimage pause invoked as \$0
while :; do
    sleep 0.1
done
EOF
chmod 755 pause

# 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
cat >Containerfile <<EOF
ARG ARCH=please-override-arch
FROM docker.io/\${ARCH}/alpine:3.12.0
RUN apk add busybox-extras
ADD testimage-id pause /home/podman/
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

# --squash-all    : needed by 'tree' test in 070-build.bats
podman rmi -f testimage &> /dev/null || true

# We need to use buildah because (as of 2021-02-23) only buildah has --manifest
# and because Dan says arch emulation is not currently working on podman
# (no further details).
# Arch emulation on Fedora requires the qemu-user-static package.
for arch in amd64 ppc64le s390x;do
    ${BUILDAH} bud \
               --arch=$arch \
               --build-arg ARCH=$arch \
               --manifest=testimage \
               --squash \
               .
done

# Clean up
cd /tmp
rm -rf $tmpdir

# Tag image and push (all arches) to quay.
remote_tag=quay.io/libpod/testimage:$YMD
podman tag testimage ${remote_tag}
${BUILDAH} manifest push --all  ${remote_tag} docker://${remote_tag}

# Side note: 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 :-(
#
# As of 2021-02-24 it is simply busybox, because it is super small,
# but it's complicated because of multiarch:
#
#    img=quay.io/libpod/testimage:00000001
#    buildah manifest create $img
#    for arch in amd64 ppc64le s390x;do
#        buildah pull --arch $arch docker.io/$arch/busybox:1.32.0
#        buildah manifest add $img docker.io/$arch/busybox:1.32.0
#    done
#    buildah manifest push --all $img docker://$img
#