Check if newer docker image available.

check_docker_newer_tag.sh

#!/bin/bash
# ensure running bash
if ! [ -n "$BASH_VERSION" ];then
    echo "this is not bash, calling self with bash....";
    SCRIPT=$(readlink -f "$0")
    /bin/bash $SCRIPT
    exit;
fi


REGISTRY="my.registry.com:5000"
REPOSITORY="awesome-project-of-awesomeness"


LATEST="`wget -qO- http://$REGISTRY/v1/repositories/$REPOSITORY/tags`"
LATEST=`echo $LATEST | sed "s/{//g" | sed "s/}//g" | sed "s/\"//g" | cut -d ' ' -f2`

RUNNING=`docker inspect "$REGISTRY/$REPOSITORY" | grep Id | sed "s/\"//g" | sed "s/,//g" |  tr -s ' ' | cut -d ' ' -f3`

if [ "$RUNNING" == "$LATEST" ];then
    echo "same, do nothing"
else
    echo "update!"
    echo "$RUNNING != $LATEST"
fi