Download backup containing Postgres and Redis dumps from S3 and import into local db

import_backup.rake

desc 'Download and import the lastest backup from S3'
task import_backup: :environment do
  # Configure AWS
  AWS.config \
    access_key_id:     Settings.aws.backup.key,
    secret_access_key: Settings.aws.backup.secret,
    region:            Settings.aws.backup.region

  # Download and extract backup file
  bucket_name = 'kc-backups'
  bucket = AWS::S3.new.buckets[bucket_name]
  last_backup = bucket.objects.with_prefix('productwidgets/').map(&:key).last
  puts "Last backup: #{last_backup}"
  tmp_file = Rails.root.join('tmp', [bucket_name, last_backup.gsub(%r(/), '_')].join('_'))
  if File.exists?(tmp_file)
    puts 'Already downloaded.'
  else
    puts 'Downloading...'
    open tmp_file, 'w' do |file|
      file.write bucket.objects[last_backup].read.force_encoding(Encoding::UTF_8)
    end
  end
  extract_folder = File.join(File.dirname(tmp_file), File.basename(tmp_file).gsub(/[^0-9a-z]/, '_'))
  if File.exists?(extract_folder)
    puts 'Already extracted.'
  else
    puts 'Extracting...'
    %x(
      mkdir -p #{extract_folder} &&
      cd #{extract_folder} &&
      tar xvzf #{tmp_file}
    )
  end

  # Import Postgres
  postgres_backup_gz = "#{extract_folder}/backup/databases/PostgreSQL.sql.gz"
  raise 'No gzipped Postgres backup file found.' unless File.exist?(postgres_backup_gz)
  postgres_backup = postgres_backup_gz.sub(/\.gz\z/, '')
  if File.exists?(postgres_backup)
    puts 'Postgres backup already extracted.'
  else
    puts 'Extracting Postgres backup...'
    %x(gunzip -fc #{postgres_backup_gz} > #{postgres_backup})
  end
  raise "Could not extract gzipped Postgres backup file #{postgres_backup_gz} to #{postgres_backup}." unless File.exists?(postgres_backup)
  db_config = ActiveRecord::Base.configurations[Rails.env].symbolize_keys
  puts 'Importing Postgres backup...'
  %x(
    bundle exec rake db:drop &&
    bundle exec rake db:create &&
    psql #{db_config[:database]} < #{postgres_backup}
  )

  # Import Redis
  redis_backup_gz = "#{extract_folder}/backup/databases/Redis.rdb.gz"
  raise 'No gzipped Redis backup file found.' unless File.exist?(redis_backup_gz)
  redis_backup = redis_backup_gz.sub(/\.gz\z/, '')
  if File.exist?(redis_backup)
    puts 'Redis backup already extracted.'
  else
    puts 'Extracting Redis backup...'
    %x(gunzip -c #{redis_backup_gz} > #{redis_backup})
  end
  puts 'Importing Redis backup...'
  # TODO: Check if Redis is running using `redis-cli ping`. If it is, raise error saying it has to be stopped before importing backup
  %x(cp #{redis_backup} #{Rails.root.join('tmp', 'redis.rdb')})
end