clone_with_backup

#!/usr/bin/env ruby

require 'fileutils'
require 'yaml'
require 'shellwords'

include FileUtils

def copy_backup base, target, last_target, remove_last = false
  if File.exists?(last_target)
    rm_r last_target
  end
  if File.exists?(target)
    mv target, last_target
  end
  system "cp", "-al", base, target
  if remove_last and File.exists?(last_target)
    rm_r last_target
  end
end

require 'optparse'

verbose = false
dry_run = false

OptionParser.new do |opts|
  opts.banner = "Usage: example.rb [options]"

  opts.on("-v", "--[no-]verbose", "Run verbosely") do |v|
    verbose = v
  end
  opts.on("-n", "--[no-]dry-run", "Dont process") do |v|
    dry_run = v
  end
end.parse!

if ARGV.size != 1
  raise "usage: #$0 [-v] [-n] <root|config>"
end

root = ARGV.first
if File.directory? root
  config_file = File.join(root, "config.yml")
else
  config_file = root
  root = nil
end

config = YAML.load(File.read(config_file))

remote = config["remote"]
id_file = config["key"]
id_files = ([id_file] + config.fetch("keys",  [])).compact
paths = config["paths"]
root = config["root"] || root
options = config["options"]
timeout_hours = config["timeout_hours"] || 6
timeout = timeout_hours * 3600
bwlimit = config["bwlimit"] || 100
remove_last = config["remove_last"] || false
ssh_options = config["ssh_options"] || {}

raise "No root defined" unless root

if paths.nil?
  paths = { "root" => "/" }
end

known_hosts_file = File.expand_path("~/.ssh/known_hosts")
if File.exists? known_hosts_file
  known_hosts = File.read(known_hosts_file).split("\n")
else
  known_hosts = []
end

if known_hosts.grep(/^#{Regexp.escape remote} /).empty?
  host_key = %x(ssh-keyscan -t rsa,dsa #{remote} 2>/dev/null)
  puts "Adding host key #{host_key}"
  known_hosts << host_key
  File.open(known_hosts_file, "w") { |f| f.puts known_hosts.join("\n") }
end

now = Time.now
name = "current"

paths.each do |path_name, path|
  dest = File.join(root, path_name)
  mkpath dest
  backup_dir = File.join(dest, name)

  ssh_args = []
  id_files.each do |id_file|
    ssh_args += ["-i", id_file]
  end
  ssh_options.each do |name, value|
    ssh_args += ["-o", "#{name}=#{Shellwords.escape(value)}"]
  end
  ssh_args = ssh_args.join(" ")

  cmd = [
    "/usr/bin/ionice", "-c", "3",
    "/usr/bin/nice",
    "/usr/bin/timeout", timeout.to_s,
    "/usr/bin/rsync",
    "--archive",
    "--one-file-system",
    "--delete-delay",
    "--numeric-ids",
    "--partial",
    "--bwlimit=#{bwlimit}",
    # "--rsync-path='nice rsync'",
    "--rsh", "ssh #{ssh_args}",
  ]
  cmd << "--verbose" if verbose
  cmd << "--dry-run" if dry_run
  cmd += options if options
  cmd += [
    remote + ":" + path,
    backup_dir,
  ]

  puts cmd.inspect if verbose
  unless system(*cmd)
    exit_status = $?.exitstatus
    STDERR.puts("rsync failed (exit status #{exit_status})")
  end

  target = File.join(dest, "month")
  last_target = File.join(dest, "month.last")
  if now.day == 1 or !File.exists?(target)
    copy_backup(backup_dir, target, last_target, remove_last)
  end

  target = File.join(dest, "week")
  last_target = File.join(dest, "week.last")
  if now.wday == 0 or !File.exists?(target)
    copy_backup(backup_dir, target, last_target, remove_last)
  end
end