registry-cleanup

#!/bin/bash
# Check arguments.
if [ "x$1" == "x"  ] || [ "x$2" == "x" ] || [ "x$3" == "x" ]
then
  # Print error.
  echo "Error: Missing arguments."
  # Print usage.
  echo "Usage: $(basename "$0") registry max_images max_age"
  # Exit.
  exit 1
fi

# Get registry, maximum images and maximum age.
registry="$1/v2"
max_images="$(( $2 + 1 ))"
max_age="$(( $(date "+%s") - $3 * 86400 ))"

# Gets repositories.
function get_repositories {
  # Get repositories.
  curl --silent "$registry/_catalog" | jq -r ".repositories[]"
}

# Gets tags by repository.
function get_tags {
  # Get repository.
  repository="$1"

  # Get tags by repository.
  curl --silent "$registry/$repository/tags/list" | jq -r ".tags[]"
}

# Gets image by repository and tag.
function get_image {
  # Get repository and tag.
  repository="$1"
  tag="$2"

  # Get image by repository and tag.
  curl --silent "$registry/$repository/manifests/$tag" --header "Accept: application/vnd.docker.distribution.manifest.v2+json" | jq -r ".config.digest"
}

# Gets created by repository and image.
function get_created {
  # Get repository and image.
  repository="$1"
  image="$2"

  # Get created by repository and image.
  created="$(curl --silent "$registry/$repository/blobs/$image" | jq -r ".created")"

  # Convert to seconds.
  date --date "$created" "+%s"
}

# Deletes tag by repository and tag.
function delete_tag {
  # Get repository and tag.
  repository="$1"
  tag="$2"

  # Get digest by repository and tag.
  digest="$(curl --silent "$registry/$repository/manifests/$tag" --header "Accept: application/vnd.docker.distribution.manifest.v2+json" --head | grep "^Docker-Content-Digest\:.*$" | awk '{print $2}' | tr --delete '\r')"

  # Delete tag by repository and digest.
  curl --silent "$registry/$repository/manifests/$digest" --request DELETE
}

# Get repositories.
repositories=$(get_repositories)

# Iterate repositories.
for repository in $repositories
do
  # Get tags by repository.
  tags=$(get_tags "$repository")

  # Iterate tags.
  for tag in $tags
  do
    # Get image by repository and tag.
    image="$(get_image "$repository" "$tag")"

    # Get created by repository and image.
    created="$(get_created "$repository" "$image")"

    echo "$created $image $tag"
  done > /tmp/tags

  # Get images to delete.
  awk '{print $1" "$2}' /tmp/tags | sort --numeric-sort --reverse --unique | tail --lines "+$max_images" > /tmp/images

  # Iterate images.
  while read line
  do
    # Get created.
    created="$(echo "$line" | awk '{print $1}')"

    # Check age.
    if [ "$created" -lt "$max_age" ]
    then
      # Get image.
      image="$(echo "$line" | awk '{print $2}')"

      # Get tags to delete.
      tags=$(grep "$image" /tmp/tags | awk '{print $3}')

      # Iterate tags to delete.
      for tag in $tags
      do
        # Log deletion.
        echo "DELETE $repository:$tag [image: $image] [created: $created]"
        # Delete tag.
        delete_tag "$repository" "$tag"
      done
    fi
  done < /tmp/images
done

# Run Docker Registry garbage collection.
registry garbage-collect /etc/docker/registry/config.yml