diff options
Diffstat (limited to 'lib/byteback/backup_directory.rb')
| -rw-r--r-- | lib/byteback/backup_directory.rb | 175 |
1 files changed, 111 insertions, 64 deletions
diff --git a/lib/byteback/backup_directory.rb b/lib/byteback/backup_directory.rb index f0ceabc..e5ab8c0 100644 --- a/lib/byteback/backup_directory.rb +++ b/lib/byteback/backup_directory.rb @@ -1,13 +1,113 @@ module Byteback + + # Represents a particular timestamped backup directory + class Snapshot + class << self + # What order to remove snapshots in to regain disk space? + # + # Order backups by their closeness to defined backup times, which are + # listed in a set order (i.e. today's backup is more important than yesterday's). + # + BACKUP_IMPORTANCE = [0, 1, 2, 3, 7, 14, 21, 28, 56, 112] + + def sort_by_importance(snapshots_unsorted, now=Time.now) + snapshots_sorted = [] + + # FIXME: takes about a minute to sort 900 items, + # seems like that ought to be quicker than O(n^2) + # + while !snapshots_unsorted.empty? + BACKUP_IMPORTANCE.each do |days| + target_time = now - (days*86400) + closest = snapshots_unsorted.inject(nil) do |best, snapshot| + if best.nil? || (snapshot.time-target_time).abs < (best.time-target_time).abs + snapshot + else + best + end + end + break unless closest + snapshots_sorted << snapshots_unsorted.delete(closest) + end + end + + snapshots_sorted + end + end + + attr_reader :backup_directory, :path + + def initialize(backup_directory, snapshot_path) + @backup_directory = backup_directory + @path = snapshot_path + time # throws ArgumentError if it can't parse + nil + end + + def time + Time.parse(path) + end + + def <=>(b) + time <=> b.time + end + + def create!(from) + system_no_error("btrfs subvolume snapshot #{from} #{path}") + end + + def delete! + system_no_error("btrfs subvolume delete #{path}") + end + + # Returns the size of the given snapshot (runs du, may be slow) + # + # Would much prefer to take advantage of this feature: + # http://dustymabe.com/2013/09/22/btrfs-how-big-are-my-snapshots/ + # but it's not currently in Debian/wheezy. + # + def du + `du -s -b #{path}`.to_i + end + + protected + + def system_no_error(*args) + args[-1] += " > /dev/null" unless @verbose + raise RuntimeError.new("Command failed: "+args.join(" ")) unless + system(*args) + end + end + # Represent a directory full of backups where "current" is a subvolume # which is snapshotted to frozen backup directories called e.g. # "yyyy-mm-ddThh:mm+zzzz". # class BackupDirectory + class << self + # Return all backup directories + # + def all + Dir.new(ENV['HOME']).entries.map do |entry| + next if entry[0] == '.' + name = File.expand_path(ENV['HOME'] + "/" + entry) + File.directory?(name + "/current") ? BackupDirectory.new(name) : nil + end. + compact + end + + # Returns every snapshot in every backup directory + # + def all_snapshots + all.map { |dir| dir.snapshots }.flatten + end + end + attr_reader :dir def initialize(dir) @dir = Dir.new(dir) + raise Errno::ENOENT unless File.directory?(dir) current end @@ -21,83 +121,30 @@ module Byteback # Return an array of Times representing the current list of # snapshots. # - def snapshot_times + def snapshots @dir.entries.map do |entry| + next if entry[0] == '.' || entry == 'current' + snapshot_path = File.expand_path(@dir.path + "/" + entry) + next unless File.directory?(snapshot_path) begin - Time.parse(entry) - rescue ArgumentError => error + Snapshot.new(self, snapshot_path) + rescue ArgumentError => ae + # directory name must represent a parseable Time nil end end. - compact. - sort - end - - # What order to remove snapshots in to regain disk space? - # - # Order backups by their closeness to defined backup times, which are - # listed in a set order (i.e. today's backup is more important than yesterday's). - # - BACKUP_IMPORTANCE = [0, 1, 2, 3, 7, 14, 21, 28, 56, 112] - def snapshot_times_by_importance - now = Time.now - snapshot_times_unsorted = snapshot_times - snapshot_times_sorted = [] - while !snapshot_times_unsorted.empty? - BACKUP_IMPORTANCE.each do |days| - target_time = now + (days*86400) - closest = snapshot_times_unsorted.inject(nil) do |best, time| - if best.nil? || (time-target_time).abs < (best-target_time).abs - time - else - best - end - end - break unless closest - snapshot_times_sorted << snapshot_times_unsorted.delete(closest) - end - end - snapshot_times_sorted - end - - # Returns the size of the given snapshot (runs du, may be slow) - # - # Would much prefer to take advantage of this feature: - # http://dustymabe.com/2013/09/22/btrfs-how-big-are-my-snapshots/ - # but it's not currently in Debian/wheezy. - # - def snapshot_size(time=snapshot_times.last) - `du -s -b #{snapshot_path(time)}`.to_i - end - - def average_snapshot_size(number=10) - snapshot_times.sort[0..number].inject(0) { |total, time| snapshot_size(time) } / number + compact end # Create a new snapshot of 'current' # - def new_snapshot! - system_no_error("btrfs subvolume snapshot -r #{current.path} #{snapshot_path}") - end - - def delete_snapshot!(time) - system_no_error("btrfs subvolume delete #{snapshot_path(time)}") + def new_snapshot!(time = Time.now) + snapshot_path = time.strftime("%Y-%m-%dT%H:%M%z") + Snapshot.new(self, snapshot_path).create!(current.path) end def current Dir.new("#{dir.path}/current") end - - def snapshot_path(time=Time.now) - "#{dir.path}/#{time.strftime("%Y-%m-%dT%H:%M%z")}" - end - - protected - - def system_no_error(*args) - args[-1] += " > /dev/null" unless @verbose - raise RuntimeError.new("Command failed: "+args.join(" ")) unless - system(*args) - end end end |