dockercache

#!/usr/bin/env bash

function cache_images() {
  images_to_cache=$( docker images --format='{{.Repository}}:{{.Tag}},{{.ID}},{{.Size}}' | grep -v '<none>' | sort | uniq )
  echo "Caching the following images"
  echo "$images_to_cache"
  if [ -n "$images_to_cache" ]; then
    rm -rf $cached_images_path
    mkdir $cached_images_path
    i=0
    for image_line in ${images_to_cache[@]}; do
      i=$(expr $i + 1)
      image_filename=$( echo "image_$i" )
      image_name=$( echo "$image_line" | cut -d , -f 1 )

      printf "Saving image $( echo ${image_name} ) to $( echo $cached_images_path/$image_filename.tar )\n"
      docker save -o $cached_images_path/$image_filename.tar $(echo ${image_name})
    done
  else
    echo "No images found."
  fi
}

function restore_images() {

  if [ -d $cached_images_path ] && [ -e $cached_image_metadata_path ]; then
    echo "Restoring images ..."
    cached_images=$(ls $cached_images_path);

    for image_archive in ${cached_images[@]}; do
      docker load -i $cached_images_path/$image_archive
    done

    echo "Images restored."
  else
   echo "No image backup found from $cached_images_path"
   exit 1
  fi
}

function docker-cache() {
  echo "Running $CMD for $DIR"
  usage="Usage: cat docker-cache | CMD=restore DIR=mydir bash"
  if [ -z $CMD ]; then
    echo "$usage"
    exit 1
  fi

  if [ -z $DIR ]; then
    echo "$usage"
    exit 1
  fi

  destination=$DIR
  cached_images_path="$destination/docker-images"

  case "$CMD" in
    "snapshot" )
      cache_images
      ;;
    "restore" )
      restore_images
      ;;
    * )
      echo "'$CMD' action unknown"
      echo "$usage"
      ;;
  esac
}

docker-cache "$@"