Clean up untagged manifests in private docker registry

cleanupManifestsWithoutTags.sh

#!/bin/bash

REGISTRY_DIR=/storage/data/docker-registry/docker/registry/v2/repositories
REGISTRY_URL=http://127.0.0.1:5000
# Set CURLOPTS to "--insecure" to disable TLS certificate verification
CURLOPTS=""

if [ -z "$REGISTRY_DIR" -o ! -d "$REGISTRY_DIR" ]; then
   echo "$0: error: REGISTRY_DIR not specified or does not exist"
   exit 1
fi

export LC_ALL=C
set -o pipefail
# Turn on nullglob
shopt -s nullglob

manifests_without_tags=$(comm -23 <(find ${REGISTRY_DIR}/{*,*/*}/_manifests/revisions/sha256 -type f -name link -printf '%h\n' | \
				awk -F "/" '{print $(NF)}' | \
				sort) \
				<(find ${REGISTRY_DIR}/{*,*/*}/_manifests/tags/*/current -type f -name link -exec sed -e 's/^sha256://g' -e '/.*/a\' {} \; | \
				sort))
if [ $? -ne 0 ]; then
   echo "$0: error: failed to analyze manifests"
   exit 1
fi

total_count=$(echo ${manifests_without_tags} | wc -w)
count=0
REGISTRY_DIR_escaped="$(echo ${REGISTRY_DIR}/ | sed 's/\//\\\//g')"
for manifest in ${manifests_without_tags};
    do
        repo="$(find ${REGISTRY_DIR}/{*,*/*}/_manifests/revisions/sha256/${manifest} -type f -name link | \
                sed -e "s/${REGISTRY_DIR_escaped}//" -e "s/\/_manifests\/revisions\/sha256\/${manifest}\/link//")"
        if [ $? -ne 0 ]; then
           echo "$0: warning: failed to find the repository name for manifest $manifest"
           continue
        fi

        curl -s -X DELETE ${CURLOPTS} "${REGISTRY_URL}/v2/${repo}/manifests/sha256:${manifest}" > /dev/null
        retval=$?
        if [ $retval -ne 0 ]; then
           echo "$0: warning: failed to delete $repo using curl on $REGISTRY_URL (retval: $retval)"
        fi
        
        ((count++))
        echo "$0: Deleted $count of $total_count manifests, manifest for repo \"$repo\" deleted."
    done