Rails Postgres Database Snapshots

backup.rake

namespace :db do
  desc "Backup the database to a file and manage archives"
  task :backup => [:environment] do
    datestamp = Time.now.strftime("%Y-%m-%d_%H-%M-%S")
    database = Rails.env.downcase
    max_backups = 48
    base_path = "db"
    backup_base = File.join(base_path, 'backups')
    backup_file = "#{Rails.env}_#{datestamp}.db.gz"
    backup_file_path = File.join(backup_base, backup_file)

    # create
    FileUtils.makedirs(backup_base)
    sh "pg_dump #{database} | gzip -c > #{backup_file_path}"
    system "cd #{backup_base} && ln -fs #{backup_file} latest_#{Rails.env}_db.gz"
    puts "created backup: #{backup_file}"

    # remove archives
    all_backups = Dir.glob(File.join(backup_base, "#{Rails.env}*.gz")).sort.reverse
    if all_backups.size > max_backups
      unwanted_backups = all_backups[max_backups..-1]
      unwanted_backups.each do |unwanted_backup|
        FileUtils.rm(unwanted_backup)
        puts "deleted #{unwanted_backup}"
      end
      puts "Deleted #{unwanted_backups.length} backups, #{all_backups.length - unwanted_backups.length} backups available"
    end
  end
end