This script can be used to copy all docker images from one GitLab-project to another. It was created because in GitLab it's not possible to move projects that contain docker images.

copy_images.sh

#!/usr/bin/env bash

# This script can be used to copy all docker images from one GitLab-project to another. 
# It was created because in GitLab it's not possible to move projects that contain docker images.
#
# Related issue: https://gitlab.com/gitlab-org/gitlab/-/issues/18383
#
# Author: Daniel Estermann <estermad@apache.org>
# Thanks to komar <komar@core.org.ua> for his brilliant support

ME=$(basename "$0")
DEPENDS="docker curl jq tac"

die() {
  if [[ "$*" && -t 2 ]]; then
    printf "\e[31;1m%s\e[0m\n" "$*" >&2
  else
    printf "%s\n" "$*" >&2
  fi
  exit 1
}

usage() {
  cat <<- EOM
		Usage: $ME <gitlab-server> <path-to-project> <new-path-to-project>

		Example: $ME gitlab.com johndoe/foo johndoe/bar
	EOM
  exit 1
}

[[ ${GITLAB_TOKEN} ]] || die "Please provide an access token via the environment variable GITLAB_TOKEN"

for CMD in $DEPENDS; do
  command -v $CMD >/dev/null 2>&1 || die "This script requires $CMD but it's not installed. Aborting."
done

docker ps >/dev/null 2>&1 || die "This script requires docker but its engine is unreachable. Aborting."

[[ ${1} && ${2} && ${3} ]] || usage

PROJECT_NS=${2//\//%2F}

REPOSITORY_IDS=$(curl -s -H "PRIVATE-TOKEN:${GITLAB_TOKEN}" \
                   "https://$1/api/v4/projects/${PROJECT_NS}/registry/repositories/" |
                     jq -r '.[].id' 2>/dev/null)
[[ ${REPOSITORY_IDS} ]] || die "$1/$2 has no docker images"

TMPFILE=$(mktemp -u /tmp/$ME.XXXXXX)

for REPOSITORY_ID in $REPOSITORY_IDS; do

  TAGS_URL="https://$1/api/v4/projects/${PROJECT_NS}/registry/repositories/${REPOSITORY_ID}/tags?per_page=100"
  
  TOTAL_PAGES=$(curl -sI -X HEAD -H "PRIVATE-TOKEN:${GITLAB_TOKEN}" ${TAGS_URL} |
                    sed -nE 's/X-Total-Pages:[[:space:]]*([^'$'\r'']*)'$'\r''?/\1/ip')
  [[ $TOTAL_PAGES =~ ^[0-9]+$ ]] || die "Error getting total page number using HTTP HEAD on $TAGS_URL (got $TOTAL_PAGES)"

  for PAGE in $(seq 1 $TOTAL_PAGES); do
    curl -s -H "PRIVATE-TOKEN:${GITLAB_TOKEN}" "${TAGS_URL}&page=${PAGE}" |
        jq -r '.[].location'
  done |
    sed -E "s#(.*)#docker pull \1 \&\& docker tag \1 \1#g
            s#(.*)($2)(.*:.*)#\1$3\3#i" |
      tee -a $TMPFILE

done

cat << EOM >> $TMPFILE
while true; do
    read -p "Do you want to push the images now? [Y/n] " yn
    case \${yn:-Y} in
        [Yy]* ) break;;
        * ) echo "Abort."; exit;;
    esac
done
EOM

tac $TMPFILE | sed '1,7d' | tac |
  sed -E "s#.* (.*)#docker push \1#" |
    tee -a $TMPFILE

[[ -f $TMPFILE ]] &&
  chmod +x $TMPFILE &&
    echo "You can now review the generated script in stdout or in $TMPFILE and if it looks fine for you just execute it." ||
      die "Something went wrong, sorry :("

@JanWendler I just tested the script with our internal GitLab installation and with gitlab.com - it works with both, so the HTTP header X-Total-Pages is available. Now there might be an incompatibility with the sed expression, as it is quite complicated.

Do you know if at least the validation in line 57 worked for you? What did you get as an output there?

To investigate your problem further, it would be helpful to see the output of the script in tracing mode. To do this, simply append -x to the shebang in line 1. And don`t forget to mask sensitive data if you want to paste the logs ;-)

@Smasherr This is the output:

$ ./copy_images.sh <our_server> <original_repo> jan.wendler/temp
++ basename ./copy_images.sh
+ ME=copy_images.sh
+ DEPENDS='docker curl jq tac'
+ [[ -n <Token> ]]
+ for CMD in $DEPENDS
+ command -v docker
+ for CMD in $DEPENDS
+ command -v curl
+ for CMD in $DEPENDS
+ command -v jq
+ for CMD in $DEPENDS
+ command -v tac
+ docker ps
+ [[ -n <our_server> ]]
+ [[ -n <original_repo> ]]
+ [[ -n jan.wendler/temp ]]
+ PROJECT_NS=<original_repo_%2F>
++ curl -s -H PRIVATE-TOKEN:<Token> https://<our_server>/api/v4/projects/<original_repo_%2F>/registry/repositories/
++ jq -r '.[].id'
+ REPOSITORY_IDS=1702
+ [[ -n 1702 ]]
++ mktemp -u /tmp/copy_images.sh.XXXXXX
+ TMPFILE=/tmp/copy_images.sh.AIoZz4
+ for REPOSITORY_ID in $REPOSITORY_IDS
+ TAGS_URL='https://<our_server>/api/v4/projects/<original_repo_%2F>/registry/repositories/1702/tags?per_page=100'
++ curl -sI -X HEAD -H PRIVATE-TOKEN:<Token> 'https://<our_server>/api/v4/projects/<original_repo_%2F>/registry/repositories/1702/tags?per_page=100'
++ sed -nE 's/X-Total-Pages:[[:space:]]*([^]*)?/\1/ip'
sed: -e expression #1, char 41: unterminated `s' command
+ TOTAL_PAGES=
+ [[ '' =~ ^[0-9]+$ ]]
+ die 'Error getting total page number using HTTP HEAD on https://<our_server>/api/v4/projects/<original_repo_%2F>/registry/repositories/1702/tags?per_page=100 (got )'
+ [[ -n Error getting total page number using HTTP HEAD on https://<our_server>/api/v4/projects/<original_repo_%2F>/registry/repositories/1702/tags?per_page=100 (got ) ]]
+ [[ -t 2 ]]
+ printf '\e[31;1m%s\e[0m\n' 'Error getting total page number using HTTP HEAD on https://<our_server>/api/v4/projects/<original_repo_%2F>/registry/repositories/1702/tags?per_page=100 (got )'
Error getting total page number using HTTP HEAD on https://<our_server>/api/v4/projects/<original_repo_%2F>/registry/repositories/1702/tags?per_page=100 (got )
+ exit 1

I'm working on Windows 10 with an elevated gitbash console. I hope this helps : )