Ghetto Docker Update

update-check.sh

#!/bin/sh
RUNNING="$(docker ps --format "{{ .ID }}" | xargs docker inspect --format "{{ .Image }}" | xargs docker inspect --format "{{ .Id }} {{ .RepoTags }}")"
AVAILABLE="$(docker images --format "{{ .ID }} [{{ .Repository }}:{{ .Tag }}]" --no-trunc)"
NEEDS_UPDATE=0
echo "${RUNNING}" | while read line; do
    current_id=$(echo "${line}" | awk '{print $1}')
    current_tag=$(echo "${line}" | awk '{print $2}')
    updated_id=$(echo "${AVAILABLE}" | grep -F "${current_tag}" | awk '{print $1}')
    if [ "$current_id" != "$updated_id" ]; then
        echo "Update required for ${current_tag}"
        NEEDS_UPDATE=1
    fi
done
exit ${NEEDS_UPDATE}