Cross Reference: /ontohub/script/backup

	backup revision 6cdc461aada609d57d50ff675d29b15378717ff2
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#!/usr/bin/env ruby
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper# Description
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#   This backup script creates and restores backups of ontohub data. It includes:
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#     * bare git repositories (data/repositories)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#     * named symlinks to git repositories (data/git_daemon)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#     * the postgres database
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper# Usage
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#   To create a backup, run this script with the argument `create`:
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#     $ script/backup create
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#   Then a backup named with the current date and time is created in the
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#   backup directory (see below).
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#   To restore a backup, run this script with the argument `restore <backup name>`
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#     $ script/backup restore 2015-01-01_00-00
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#   Then the selected backup is fully restored
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper# Backup directory
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#   For development machines, the backup directory is:
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#     <rails root>/tmp/backup/
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#   And for production machines, the backup directory is:
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#     /home/ontohub/ontohub_data_backup
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper# Super user privileges
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#   To create and restore, we need root privileges. Otherwise file modes are not
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#   preserved. This script will call `sudo` when needed and inform you about the
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#   reason for calling `sudo`. If you don't allow sudo, a backup will be created
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#   or restored anyway, but the file modes and ownership are not preserved.
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#   Then, you need to adjust them manually.
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper# Maintenance mode
5c39d8f041417518a02ce2c941d96c2d33b2a364Mark de Reeper#   While backing up and restoring the data, the maintenance mode is activated.
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#   This way we guarantee data consistency of the backup.
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeperrequire 'tmpdir.rb'
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeperrequire 'fileutils'
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeperrequire 'pathname'
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeperrequire 'open3'
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reepermodule Backup
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper  class Backup
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    # Amount of backups that have to be there at least
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    BACKUPS_COUNT = 30
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    # Backups are kept for at least 365 days
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    BACKUPS_VALIDITY_TIME = 365 * 60 * 60 * 24
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    MAINTENANCE_FILE = 'maintenance.txt'
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    SQL_DUMP_FILE = 'ontohub_sql_dump.postgresql'
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    REPOSITORY_FILE = 'ontohub_repositories.tar.gz'
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    DATA_DIRS = %w(data/repositories data/git_daemon)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    attr_reader :db_name, :data_root, :backup_root, :backup_instance_dir
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    attr_reader :dry_run, :verbose, :sql_dump_as_postgres_user
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    def initialize(db_name, data_root, backup_root,
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      verbose: false, dry_run: true, sql_dump_as_postgres_user: false)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      @db_name = db_name
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      @data_root = Pathname.new(data_root)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      @backup_root = Pathname.new(backup_root)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      @dry_run = dry_run
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      @verbose = verbose
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      @sql_dump_as_postgres_user = sql_dump_as_postgres_user
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    def create
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      puts 'Creating backup...'
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      enable_maintenance_mode
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      initialize_backup
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      create_sql_dump
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      create_repository_archive
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      # We needed to create the directory for the script to continue later on.
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      Dir.rmdir(backup_instance_dir) if dry_run
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      disable_maintenance_mode
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      puts "Created backup in #{backup_instance_dir}"
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      self.class.prune(backup_root)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    def restore(backup_name)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      enable_maintenance_mode
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      initialize_restore(backup_name)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      restore_sql_dump
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      restore_repository_archive
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      disable_maintenance_mode
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      puts "Restored backup from #{backup_instance_dir}"
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    def self.prune(backup_root)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      if !Dir.exists?(backup_root)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper        $stderr.puts "Nothing to prune: There is no backup directory."
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper        return
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      now = Time.now
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      backup_dirs_allowed_to_delete(Dir.new(backup_root).entries).each do |dir|
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper        backup = backup_root.join(dir)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper        if now - File.new(backup).ctime > BACKUPS_VALIDITY_TIME
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper          puts "removing old backup: #{dir}"
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper          FileUtils.rm_r(backup)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper        end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    protected
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    def new_backup_name
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      Time.now.strftime("%Y-%m-%d_%H-%M-%S")
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    def initialize_backup
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      @backup_instance_dir = backup_root.join(new_backup_name)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      puts "FileUtils.mkdir_p #{backup_instance_dir}" if verbose
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      # Create directory even in dry run to let the script continue.
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      FileUtils.mkdir_p(backup_instance_dir)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    def create_sql_dump
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      puts 'Creating SQL dump...'
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      Dir.chdir(backup_instance_dir) do
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper        exec('pg_dump', *pg_user_switch, '-Fc', db_name,
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper          file_dest: SQL_DUMP_FILE)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    def create_repository_archive
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      puts 'Creating repository archive...'
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      Dir.chdir(data_root.join('..')) do
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper        archive_file = backup_instance_dir.join(REPOSITORY_FILE)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper        exec('tar', verbose ? '-v' : '', '-czf', archive_file.to_s,
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper          *DATA_DIRS.map(&:to_s))
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    def initialize_restore(backup_name)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      @backup_instance_dir = backup_root.join(backup_name)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      unless Dir.exists?(backup_instance_dir)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper        $stderr.puts (
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper          "Error: Backup '#{backup_name}' does not exist in #{backup_root}.")
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper        exit
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    def restore_sql_dump
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      'Restoring SQL dump...'
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      Dir.chdir(backup_instance_dir) do
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper        exec('pg_restore', '-c', *pg_user_switch, '-d', db_name, SQL_DUMP_FILE)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    def restore_repository_archive
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      puts 'Restoring repository archive...'
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      Dir.chdir(data_root.join('..')) do
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper        tmpdir = Dir.mktmpdir
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper        move_data_dirs_to_tmpdir(tmpdir)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper        begin
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper          extract_archive
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper          remove_tmpdir(tmpdir)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper        rescue => e
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper          puts <<-MSG
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de ReeperAn error occured while restoring the repositories:
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper#{e.message}
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de ReeperYou can find the pre-restore repositories at #{tmpdir}
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de ReeperDo something about it.
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper          MSG
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper          raise e
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper        end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    def move_data_dirs_to_tmpdir(tmpdir)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      puts "FileUtils.mv(#{DATA_DIRS}, #{tmpdir})" if verbose
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      FileUtils.mv(DATA_DIRS, tmpdir) unless dry_run
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    rescue Errno::EACCES
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      puts <<-MSG
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de ReeperAs the current user I have no access to move the repository data
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeperdirectories #{DATA_DIRS.join(' ')} to a temporary directory #{tmpdir}.
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de ReeperThis is used as a backup for the case of an error while restoring.
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de ReeperTo continue, I try the command again using sudo.
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      MSG
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      exec('sudo', 'mv', *DATA_DIRS.map(&:to_s), tmpdir)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    def extract_archive
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      archive_file = backup_instance_dir.join(REPOSITORY_FILE)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      puts <<-MSG
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de ReeperSuper user privileges are needed to reset the file permissions as
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeperthey were before the backup. If you refuse to enter the password
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper(Ctl-C) or enter a wrong password, only the permissions will not be
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeperrestored and all restored files will belong to the current user/group.
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      MSG
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      try_as_sudo_with_fallback('tar', verbose ? '-v' : '', '-xzf',
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper        archive_file.to_s, *DATA_DIRS.map(&:to_s))
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    end
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    def remove_tmpdir(tmpdir)
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      puts "FileUtils.remove_entry(#{tmpdir})" if verbose
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      FileUtils.remove_entry(tmpdir) # even do this in dry run
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper    rescue Errno::EACCES
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      puts <<-MSG
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de ReeperAs the current user I have no access to remove the temporary
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeperdirectory #{tmpdir}.
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de ReeperTo continue, I try the command again using sudo.
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      MSG
6406210b71fd4a97800f32f3613eea9b6a6a12ceMark de Reeper      exec('sudo', 'rm', '-r', tmpdir)
    end

    def enable_maintenance_mode
      puts 'Enabling maintenance mode...'
      puts "FileUtils.touch #{maintenance_file}" if verbose
      FileUtils.touch maintenance_file unless dry_run
    end

    def disable_maintenance_mode
      puts 'Disabling maintenance mode...'
      puts "FileUtils.rm #{maintenance_file}" if verbose
      FileUtils.rm maintenance_file unless dry_run
    end

    def exec(*args, file_dest: nil)
      puts "[executing next command in #{Dir.getwd}]" if verbose
      out = args.join(' ')
      out << " > #{file_dest}" if file_dest
      puts out if verbose
      Subprocess.run(*args, file_dest: file_dest) unless dry_run
    end

    def try_as_sudo_with_fallback(*args)
      _out, _err, exit_code = exec('sudo', *args)
      unless exit_code.success?
        sudo_not_given_fallback(*args) # Wrong sudo password
      end
    rescue Exception => e
      raise e unless e.is_a?(Interrupt) # Ctrl-C when asked for password
      sudo_not_given_fallback(*args)
    end

    def sudo_not_given_fallback(*args)
      puts 'Super user privileges not granted. Trying as normal user.'
      exec(*args)
    end

    def maintenance_file
      data_root.join(MAINTENANCE_FILE)
    end

    def pg_user_switch
      sql_dump_as_postgres_user ? %w(-U postgres) : []
    end

    def self.backup_dirs_allowed_to_delete(entries)
      entries.reject{ |entry| %w(. ..).include?(entry) }[0..-(BACKUPS_COUNT+1)]
    end
  end

  class Subprocess
    def self.run(*args, file_dest: nil)
      stdin, stdout, stderr, wait_thr, io_dest = run_streaming(*args,
        file_dest: file_dest)
      exit_code = wait_thr.value # wait for the process to finish
      io_dest.close if io_dest

      [stdout.read, stderr.read, exit_code]
    end

    def self.run_streaming(*args, file_dest: nil)
      stdin, stdout, stderr, wait_thr = Open3.popen3(*args)
      io_dest = nil
      if file_dest
        io_dest = File.open(file_dest, 'w')
        IO.copy_stream(stdout, io_dest)
      end
      [stdin, stdout, stderr, wait_thr, io_dest]
    end
  end
end

def data_root(rails_root)
  File.realpath(rails_root.join('data'))
end

def on_development_system?(rails_root)
  !File.symlink?(rails_root.join('data'))
end

# We assume, this script runs in "RAILS_ROOT/script/".
RAILS_ROOT = Pathname.new(__FILE__).dirname.join('..')
BACKUP_ROOT_PRODUCTION = '/home/ontohub/ontohub_data_backup'

DATABASE =
  if on_development_system?(RAILS_ROOT)
    'ontohub_development'
  else
    'ontohub'
  end

BACKUP_ROOT =
  if on_development_system?(RAILS_ROOT)
    RAILS_ROOT.join('tmp', 'backup')
  else
    File.realpath(BACKUP_ROOT_PRODUCTION)
  end

backup = Backup::Backup.new(DATABASE, data_root(RAILS_ROOT), BACKUP_ROOT,
  sql_dump_as_postgres_user: on_development_system?(RAILS_ROOT),
  dry_run: false, verbose: true)

case ARGV.first
when 'create'
  backup.create
when 'restore'
  if ARGV.length == 1
    $stderr.puts(
      'To restore a backup, you need to specify one with the arguments')
    $stderr.puts('"restore backup_name"')
    exit
  end
  backup_name = ARGV[1]
  backup.restore(backup_name)
when 'prune'
  Backup::Backup.prune(BACKUP_ROOT)
else
  $stderr.puts 'unknown or missing parameter'
  $stderr.puts 'use parameter "create" or "restore <backup_name>" or "prune"'
  exit
end