Class: Dreamback::Backup

Inherits:
Object
  • Object
show all
Defined in:
lib/dreamback/backup.rb

Constant Summary collapse

BACKUP_FOLDER = 
"./dreamback"

Class Method Summary collapse

Class Method Details

.rotate_backups ⇒ Object

Rotate out the backups that are past our limit



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# File 'lib/dreamback/backup.rb', line 19

def self.rotate_backups
  backup_to_link = nil
  Net::SFTP.start(Dreamback.settings[:backup_server], Dreamback.settings[:backup_server_user]) do |sftp|
    # Create the backup folder if it doesn't exist
    backup_folder_exists = false
    begin
      sftp.stat!(BACKUP_FOLDER) do |response|
        backup_folder_exists = response.ok?
      end
    rescue Net::SFTP::StatusException => e
      backup_folder_exists = false if e.code == 2
    end

    # Get a list of all backup directories
    backup_folders = []
    if backup_folder_exists
      sftp.dir.foreach(BACKUP_FOLDER) do |entry|
        # Names should be like "dreamback.20120520", so we can sort on the folder name
        backup_folders << [ entry.name, entry.name.split(".")[1].to_i ] if entry.name.include?("dreamback")
        backup_folders.sort! {|a,b| b <=> a}
      end
    else
      sftp.mkdir(BACKUP_FOLDER)
    end

    # Don't rotate if there aren't any previous folders
    unless backup_folders.empty?
      # Get yesterday's folder to link against
      backup_to_link = backup_folders.first[0]
      # If this would link us to the same folder, don't do that. Try yesterday's instead.
      if backup_to_link.eql? "dreamback." + Date.today.strftime("%Y%m%d")
        backup_to_link = "dreamback." + (Date.today - 1).strftime("%Y%m%d")
      end

      # Delete any folders older than our limit
      if Dreamback.settings[:days_to_keep]
        folders_to_delete = rotate_daily(backup_folders)
      elsif Dreamback.settings[:keep_time_machine]
        folders_to_delete = rotate_time_machine(backup_folders)[:delete]
      else
        folders_to_delete = nil
      end
      rsync_delete(folders_to_delete)
    end
  end

  backup_to_link
end

.rotate_daily(backup_folders) ⇒ Array

Rotate folders based on the number of days to keep

Parameters:

  • folders (Array) —

    to rotate in Dreamback format (dreamback.20120521)

Returns:

  • (Array) —

    list of folders to delete



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# File 'lib/dreamback/backup.rb', line 119

def self.rotate_daily(backup_folders)
  # Subtract one to account for the folder we're about to create
  # Normally we remove a folder so that our count is one less than the "days to keep"
  # However, if today's folder already exists then there's no need
  offset = backup_folders.include?("dreamback.#{Time.now.strftime("%Y%m%d")}") ? 0 : 1
  if backup_folders.length >= Dreamback.settings[:days_to_keep] - offset
    folders_to_delete = backup_folders.slice(Dreamback.settings[:days_to_keep] - offset, backup_folders.length)
    folders_to_delete.map! {|f| f[0]}
  end
  folders_to_delete ||= nil
end

.rotate_time_machine(folders, today = nil) ⇒ Hash

Use a time machine-like algorithm to rotate backups. This will keep daily backups for seven days, weeklies for three months, and monthlies forever

Parameters:

  • the (Date) —

    day to count as “today”, where the rotation will start

  • folders (Array) —

    to rotate in Dreamback format (dreamback.20120521)

Returns:

  • (Hash) —

    :keep => list of folders to retain, :delete => folders marked for deletion



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# File 'lib/dreamback/backup.rb', line 135

def self.rotate_time_machine(folders, today = nil)
  today ||= Date.today
  ymd = "%Y%m%d"

  folder_data = {}
  folders.each do |f|
    folder_data[f] = {
      :date => Date.strptime(f[1].to_s, ymd)
    }
  end

  keep = []
  one_week_ago = today - 7
  three_months_ago = today << 3

  week_hash = {}
  month_hash = {}
  folder_data.each do |k, v|
    if v[:date] >= one_week_ago
      keep << k
    elsif v[:date] >= three_months_ago
      week_hash[v[:date].cweek] = [] if week_hash[v[:date].cweek].nil?
      week_hash[v[:date].cweek] << [k, v]
    else
      ym = v[:date].strftime("%Y%m").to_i
      month_hash[ym] = [] if month_hash[ym].nil?
      month_hash[ym] << [k, v]
    end
  end

  week_hash.each do |week, dates|
    dates.sort! {|a, b| a[1][:date] <=> b[1][:date]}
  end

  week_hash.each do |week, dates|
    keep << dates.shift[0] unless dates.empty?
  end

  month_hash.each do |month, dates|
    dates.sort! {|a, b| a[1][:date] <=> b[1][:date]}
  end

  month_hash.each do |month, dates|
    keep << dates.shift[0] unless dates.empty?
  end

  keep.sort!.compact!

  # Convert elements from ["dreamback.20120701", "20120701"] to "dreamback.20120701"
  keep_clean = keep.map {|folder| folder.shift}
  delete = (folders - keep).map {|folder| folder.shift}

  { :keep => keep_clean, :delete => delete}
end

.rsync_backup(link_dir) ⇒ Object

Sync to the backup server using link-dest to save space

Parameters:

  • name (String) —

    of the most recent backup folder prior to starting this run to link against



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# File 'lib/dreamback/backup.rb', line 89

def self.rsync_backup(link_dir)
  tmp_dir_path = "~/.dreamback_tmp"
  tmp_dir = File.expand_path(tmp_dir_path)
  Dir.mkdir(tmp_dir) unless File.exists?(tmp_dir)
  user_exclusions_path = File.expand_path("~/.dreamback_exclusions")
  default_exclusions_path = File.expand_path("../exclusions.txt", __FILE__)
  exclusions_path = File.exists?(user_exclusions_path) ? user_exclusions_path : default_exclusions_path
  begin
    backup_server_user = Dreamback.settings[:backup_server_user]
    backup_server = Dreamback.settings[:backup_server]
    today = Time.now.strftime("%Y%m%d")
    Dreamback.settings[:dreamhost_users].each do |dreamhost|
      # User that we're going to back up
      user = dreamhost[:user]
      server = dreamhost[:server]
      # rsync won't do remote<->remote syncing, so we stage everything here first
      `rsync -e ssh -av --keep-dirlinks --exclude-from #{exclusions_path} --copy-links #{user}@#{server}:~/ #{tmp_dir}/#{user}@#{server}`
    end
    # Now we can sync local to remote. Only use link-dest if a previous folder to link to exists.
    link_dest = link_dir.nil? ? "" : "--link-dest=~#{BACKUP_FOLDER.gsub(".", "")}/#{link_dir}"
    `rsync -e ssh -av --delete --copy-links --keep-dirlinks #{link_dest} #{tmp_dir}/ #{backup_server_user}@#{backup_server}:#{BACKUP_FOLDER}/dreamback.#{today}`
  ensure
    # Remove the staging directory
    `rm -rf #{File.expand_path(tmp_dir_path)}`
  end
end

.rsync_delete(directories) ⇒ Object

This uses a hack where we sync an empty directory to remove files We do this because sftp has no recursive delete method



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# File 'lib/dreamback/backup.rb', line 71

def self.rsync_delete(directories)
  return if directories.nil? || directories.empty?
  empty_dir_path = File.expand_path("../.dreamback_empty_dir", __FILE__)
  empty_dir = Dir.mkdir(empty_dir_path) unless File.exists?(empty_dir_path)
  begin
    directories.each do |dir|
      `rsync --delete -a #{empty_dir_path}/ #{Dreamback.settings[:backup_server_user]}@#{Dreamback.settings[:backup_server]}:#{BACKUP_FOLDER}/#{dir}`
      Net::SFTP.start(Dreamback.settings[:backup_server], Dreamback.settings[:backup_server_user]) do |sftp|
        sftp.rmdir!("#{BACKUP_FOLDER}/#{dir}")
      end
    end
  ensure
    Dir.delete(empty_dir_path)
  end
end

.start ⇒ Object

Manage the backup process



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# File 'lib/dreamback/backup.rb', line 8

def self.start
  # rotate the backup folders
  backup_to_link = rotate_backups
  # rsync backup of dreamhost user accounts
  rsync_backup(backup_to_link)
  # mysql backup
  # TODO: Add mysql backups
end