Delete all images in order of dependency excluding selected base images for faster builds

docker_clean_ci.sh

#!/bin/bash

function list_include_item { local list="$1"; local item="$2"; if [[ $list =~ (^|[[:space:]])"$item"($|[[:space:]]) ]] ; then result=0; else result=1; fi; return $result;};
bases="alpine:latest nginx:1.11.3-alpine"
delete=
# append latest tag to each image
for item in $(docker images --format "{{.Repository}}:{{.Tag}}@{{.ID}}")
do
    export IFS=' '
    IFS='@'; arr=($item); unset IFS;
    #export IFS=' '
    `list_include_item "$bases" "${arr[0]}"` && check="yes" || check="no"
    if [[ "$check" == "yes" ]];
    then
        echo "Removing ${arr[0]} from deletion list."
    else
        delete+="${arr[0]} "
    fi
    #echo Image: ${arr[0]}
    #echo ID: ${arr[1]}
done

docker rmi $delete
docker rmi $(docker images -f "dangling=true" -q)