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#!/usr/bin/ruby
#
# Back up this system to a byteback-enabled server (just some command line
# tools and SSH setup). We aim to make sure this backups are easy, complete
# and safe for most types of hosting customer.
#
# See 'man byteback' for more information.
require 'getoptlong'
require 'resolv'
def error(message)
STDERR.print "*** #{message}\n"
exit 1
end
def verbose(message)
print "#{message}\n"
end
def help
puts <<EOF
#{$0}: Back up this system to a byteback-enabled server
Options:
--destination, -d <s>: Backup destination (i.e. user@host:/path)
--source, -s <s>: Source paths (defaults: / and /boot)
--exclude, -x <s>: Exclude paths (defaults: /swap.file, /var/backups/localhost, /var/cache)
--verbose, -v: Show rsync command and progress
--retry-number, -r <n>: Number of retries on error (default: 3)
--retry-delay, -e <n>: Wait number of seconds between retries (default: 1800)
--ssh-key, -k <s>: SSH key for connection (default: /etc/byteback/key)
--help, -h: Show this message
EOF
exit 0
end
opts = GetoptLong.new(
[ '--help', '-h', GetoptLong::NO_ARGUMENT ],
[ '--verbose', '-v', GetoptLong::NO_ARGUMENT ],
[ '--source', '-s', GetoptLong::REQUIRED_ARGUMENT ],
[ '--destination', '-d', GetoptLong::REQUIRED_ARGUMENT ],
[ '--retry-number', '-r', GetoptLong::REQUIRED_ARGUMENT ],
[ '--retry-delay', '-e', GetoptLong::REQUIRED_ARGUMENT ],
[ '--ssh-key' ,'-k', GetoptLong::REQUIRED_ARGUMENT ]
)
@ssh_key = nil
@destination = nil
@retry_number = 3
@retry_delay = 1800
@sources = nil
@excludes = nil
# Read the default destination
if File.exists?("/etc/byteback/destination")
@destination = File.read("/etc/byteback/destination").chomp
end
# Set the default SSH key
if File.exists?("/etc/byteback/key")
@ssh_key = "/etc/byteback/key"
end
# Read in the default sources
if File.exists?("/etc/byteback/sources")
@sources = File.readlines("/etc/byteback/sources").map{|m| m.chomp}
end
# Read in the default excludes
if File.exists?("/etc/byteback/excludes")
@excludes = File.readlines("/etc/byteback/excludes").map{|m| m.chomp}
end
begin
opts.each do |opt,arg|
case opt
when '--help'
help = true
when '--verbose'
$VERBOSE = true
when "--source"
@sources ||= []
@sources << arg
when "--exclude"
@excludes ||= []
@excludes << arg
when "--destination"
@destination = arg
when "--retry-number"
@retry_number = arg.to_i
when "--retry-delay"
@retry_delay = arg.to_i
when "--ssh-key"
@ssh_key = arg
end
end
rescue => err
# any errors, show the help
warn err.to_s
help = true
end
#
# Check our destination
#
if @destination =~ /^(?:(.+)@)?([^@:]+):(.+)?$/
@destination_user, @destination_host, @destination_path = [$1, $2, $3]
else
error("Destination must be a remote path, e.g. ssh@host.com:/store/backups")
end
#
# Validate & normalise source directories
#
@sources = ["/"] if @sources.nil?
error("No sources specified") if @sources.empty?
@sources = @sources.map do |s|
s = s.gsub(/\/+/,"/")
error("Can't read directory #{s}") unless File.readable?(s)
s
end
#
# Validate and normalise excludes
#
if @excludes.nil?
@excludes = ["/swap.file", "/var/backups/localhost"]
@excludes << "/var/cache/apt/archives" if File.directory?("/var/cache/apt/archives")
end
@excludes = @excludes.map do |e|
e.gsub(/\/+/,"/")
end
error("Must suply --destination or put it into /etc/bytebackup/destination") unless @destination
#
# Test ssh connection is good before we start
#
error("Could not read ssh key #{@ssh_key}") unless File.readable?(@ssh_key)
def ssh(*ssh_args)
args = ["ssh",
"-o", "BatchMode=yes",
"-x", "-a",
"-i", @ssh_key,
"-l", @destination_user,
@destination_host
] +
ssh_args.
map { |a| a ? a : "" }
print args.map { |a| / /.match(a) ? "\"#{a}\"" : a }.join(" ")+"\n" if $VERBOSE
system(*args)
end
error("Could not connect to #{@destination}") unless
ssh("byteback-receive", "--ping", ($VERBOSE ? "--verbose" : "" ))
#
# Call rsync to copy certain sources, returns exit status (see man rsync)
#
def rsync(*sources)
# Default options include --inplace because we only care about consistency
# at the end of the job, and rsync will do more work for big files without
# it.
#
args = %w(rsync --archive --numeric-ids --delete --inplace --delete --one-file-system --relative)
args += [ "--rsync-path", "rsync --fake-super"]
args += [ "--rsh", "ssh -o BatchMode=yes -x -a -i #{@ssh_key} -l #{@destination_user}"]
args << "--verbose" if $VERBOSE
args += @excludes.map { |x| ["--exclude", x] }.flatten
args += sources
args << @destination
print args.map { |a| / /.match(a) ? "\"#{a}\"" : a }.join(" ")+"\n" if $VERBOSE
system(*args)
return $?.exitstatus
end
RSYNC_EXIT_STATUSES_TO_RETRY_ON = [10,11,20,21,22,23,24,30]
# Run the file copy, retrying if necessary
#
loop do
status = rsync(*@sources)
if status === 0
break
elsif RSYNC_EXIT_STATUSES_TO_RETRY_ON.include?(status)
if @retry_number > 0
@retry_number -= 1
sleep @retry_delay
redo
else
error("Maximum number of rsync retries reached")
end
else
error("Fatal rsync error occurred (#{status})")
end
end
# Mark the backup as done on the other end
#
error("Backup could not be marked complete") unless
ssh("sudo", "byteback-snapshot", "--snapshot", ($VERBOSE ? "--verbose" : ""))
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