Get rid of old ecr images

script.rb

#!/usr/bin/env ruby
# this script will delete ECR images that are older than N days

require 'date'
require 'json'

# customize this script
repo = 'changeme'
delete_if_older_than = 180 # days

# get the list of all images
json_output = `aws ecr describe-images --repository-name #{repo} --output json --region us-west-2`
images = JSON.parse(json_output)['imageDetails']

# find the images to delete
images_to_delete = []
images.each do |i|
  date_pushed = DateTime.strptime(i['imagePushedAt'].to_s,'%s')
  age_in_days = (DateTime.now - date_pushed).to_i
  if age_in_days > delete_if_older_than
    #puts "#{i['imageDigest']} #{age_in_days}"
    images_to_delete << i
  end
end

# sanity check
puts "There are #{images.size} total"
puts "There are #{images_to_delete.size} images that will be deleted."
require 'pp'
#pp images_to_delete
puts "Is that okay?"
input = STDIN.gets.strip
exit 5 unless input =~ /^y/i

# actually delete the images
# AWS has a limit of 100 images in a batch
images_to_delete.each_slice(100) do |batch|
  image_ids = batch.map{|i| "imageDigest=#{i['imageDigest']}"}.join(' ')
  puts `aws ecr batch-delete-image --repository-name #{repo} --image-ids #{image_ids} --region us-west-2`
end

puts "Done!"