ElasticBeanstalkのDockerrun.aws.jsonから ECRにdocker imageをpush するscript

TL;DR

ElasticBeanstalkのDockerrun.aws.jsonからAmazon ECRに docker image をpushする
PrimaryなDocker Registryは docker hubなり quay.io なり、ECR以外のRegistryを利用している場合に
SecondaryなDocker RegistryとしてECRを利用するときにdocker imageをsyncする

script

# Docker image sync quay.io to Amazon ECR
# require docker login over aws cli
# command here :
#   aws ecr get-login --region ap-northeast-1
#   and exec display docker login command
#   $(aws ecr get-login --region ap-northeast-1)
#
require 'json'

def targets
  # Dockerrun.aws.json
  json = open('./Dockerrun.aws.json') do |file|
    JSON.load(file)
  end
  images = []
  json['containerDefinitions'].each do |caontainer|
    images << caontainer['image']
  end
  images
end

def docker_pull(image)
  `docker pull #{image}`
end

def tag_change(image)
  new_tag = replace_repository(image)
  `docker tag #{image} #{new_tag}`
end

def docker_push(image)
  new_tag = replace_repository(image)
  `docker push #{new_tag}`
end

def replace_repository(image)
  repository, tag = image.split(':')
  repository.gsub!(%r{quay.io/hogehoge}, ecr_host)
  return "#{repository}:latest" if ARGV[0] == 'latest'
  "#{repository}:#{tag}"
end

def ecr_host
  'xxxxxxxxxxxxxx.dkr.ecr.us-east-1.amazonaws.com'
end

targets.each do |image|
  docker_pull(image)
  tag_change(image)
  docker_push(image)
end