registry-keep-last-n-tags.sh

#!/bin/sh
# This script remove tags from local registry, keeping just the n most recents tags 
#
# based on: https://gist.github.com/jaytaylor/86d5efaddda926a25fa68c263830dac1?permalink_comment_id=4732942#gistcomment-4732942
# and on: https://stackoverflow.com/questions/31251356/how-to-get-a-list-of-images-on-docker-registry-v2
# Abels changes: 
# - Not using jq utility, just curl and native linux binaries
# - Check based tag count, removing last n versions

# Function to check if has more than n tags and remove
check_tags_more_than_n_versions() {
    # Get tag list, not sorted
    local tagurl="https://${registry}/v2/${image}/tags/list"
    echo "Searching image ${image} tags in registry ${registry} with url ${tagurl}"
    local tags=$(curl -k -s -u $user:$password "$tagurl" | awk -F: '{print $3}' | sed -e 's/[][]//g' -e 's/\"//g' -e 's/ //g' -e 's/,/\n/g' | tr '}' '\n' | tr '{' '\n')

    # Filter tags that has this string (opcional)
    if [ -n "$only" ]; then
        tags=$(echo "${tags}" | grep "$only")
    fi

    # Exclude tags that has this string (opcional)
    if [ -n "$exclude" ]; then
        tags=$(echo "${tags}" | grep -v "$exclude")
    fi

    local tagsWithTS=""
    if [ -n "$tags" ]; then
        # Get created timestamp for each tag
        for tag in $tags; do
            local created_time=$(curl -k -s -u $user:$password -H 'Accept: application/vnd.docker.distribution.manifest.v1+json' -X GET https://$registry/v2/$image/manifests/$tag | grep -i v1Compatibility | head -n1 | awk -F'created' '{print $2}' | awk -F'"' '{print $3}' | sed -e 's/\\//g')
            created_time=$(echo $created_time | sed -e 's/T/ /g' | awk -F'.' '{print $1}')
            local created_timestamp=$(date -d "$created_time" +%s)
            tagsWithTS="${tagsWithTS}${created_timestamp}|${tag} "
        done

        #Sort tags by time stamp and remove from list keeplast values, keeping tags to remove
        tagsWithTS=$(echo $tagsWithTS | xargs -n1 | sort -r -n -t'|' -k1)
        tagsWithTS=$(echo $tagsWithTS | xargs -n1 | sed -n $((keeplast + 1)),1000p)

        # Tags to remove
        if [ -n "$tagsWithTS" ]; then
            for tag in $tagsWithTS; do
                tag=$(echo "$tag" | awk -F'|' '{print $2}')
                echo "Tag $tag of image $image will be deleted..."
                local tagdigest=$(curl -s -k -I -u "$user:$password" -H "Accept: application/vnd.docker.distribution.manifest.v2+json" "https://${registry}/v2/${image}/manifests/${tag}" | grep -i 'docker-content-digest: ' | awk -F': ' '{print $2}' | sed 's/[\r\n]//g')
                local url="https://${registry}/v2/${image}/manifests/${tagdigest}"
                curl -s -k -u "$user:$password" -X DELETE $url
            done
        else
            echo "No tags to delete founded for image $image."
        fi
    else
        echo "No tags found for image $image."
    fi

}

HELPMSG="
    Basic usage
        $0 -r {registry_url} -i {image-name}

    Options avaliable
        -r    registry url
        -i    image name
        -k    keep last n
        -o    keep only tags that contains this string
        -e    exclude tags if name contains this string
        -u    user 
        -p    password 

    Examples
        $0 -r registry.local:5000 -i project1
        $0 -r registry.local:5000 -i project1 -e latest
"

while getopts ":r:i:k:o:e:u:p:" opt; do
    case "$opt" in
        r) registry="$OPTARG" ;;
        i) image="$OPTARG" ;;
        k) keeplast="$OPTARG" ;;
        o) only="$OPTARG" ;;
        e) exclude="$OPTARG" ;;
        u) user="$OPTARG" ;;
        p) password="$OPTARG" ;;
        \?) echo "Opção inválida: -$OPTARG" >&2; exit 1 ;;
    esac
done

# Set keeplast default value to 10
if [ -z "$keeplast" ]; then keeplast=10; fi

# Required params 
if [ -z "$registry" ]; then echo "Error: Registry (-r) required"; echo "$HELPMSG"; exit 1; fi
if [ -z "$image" ]; then echo "Error: Image (-i) required"; echo "$HELPMSG"; exit 1; fi

check_tags_more_than_n_versions

See this line https://gist.github.com/jaytaylor/86d5efaddda926a25fa68c263830dac1