skopeo-push-maybe

#!/usr/bin/env bash
#
# Usage: ./skopeo-push-maybe <SOURCE-IMAGE> <DEST-IMAGE>
#
# Like skopeo copy but assumes that if the image already exists there is no
# need to re-upload the image.
#
# Needs skopeo 0.1.29+
set -uo pipefail

# Config
source=$1
dest=$2

## Main

# Avoid re-uploading images
out=$(skopeo inspect "${dest}" 2>&1)
es=$?

if [[ $es = 0 ]]; then
  echo "image already exists"
  exit 0
fi

# Ugly differentiator on error message output since all exit with the same
# exit status
if echo "$out" | grep "manifest unknown" >/dev/null; then
  # image doesn't exist, upload
  exec skopeo copy "$source" "$dest"
fi

# some other error
echo "$out"
exit "$es"