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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 'trollop'
require 'resolv'
@sources = ["/"]
@exclude = ["/swap.file", "/var/backups/localhost"]
def error(message)
STDERR.print "*** #{message}\n"
exit 1
end
def verbose(message)
print "#{message}\n"
end
opts = Trollop::options do
opt :destination, "Backup destination (i.e. user@host:/path)",
:type => :string
opt :source, "Source paths",
:type => :strings
opt :verbose, "Show rsync command and progress"
opt :retry_number, "Number of retries on error",
:type => :integer,
:default => 3
opt :retry_delay, "Wait number of seconds between retries",
:type => :integer,
:default => 1800
opt :ssh_key, "SSH key for connection",
:type => :string,
:default => "/etc/byteback/key"
end
@ssh_key = opts[:ssh_key]
@verbose = opts[:verbose] ? "--verbose" : nil
@sources = opts[:source] if opts[:source]
@destination = opts[:destination]
@retry_number = opts[:retry_number]
@retry_delay = opts[:retry_delay]
if !@destination && File.exists?("/etc/byteback/destination")
@destination = File.read("/etc/byteback/destination").chomp
end
error("Must suply --destination or put it into /etc/bytebackup/destination") unless @destination
_dummy, @destination_user, @destination_host, colon, @destination_path =
/^(.*)?(?:@)([^:]+)(:)(.*)?$/.match(@destination).to_a
error("Must be a remote path") unless colon
# Validate & normalise source directories
#
error("No sources specified") if @sources.empty?
@sources = @sources.map do |s|
s = s.gsub(/\/+/,"/")
error("Can't read directory #{s}") unless File.readable?(s)
s
end
# Guess destination for backup
#
if !@destination
guesses = []
hostname = `hostname -f`
Resolv::DNS.open do |dns|
suffix = hostname.split(".")[2..-1].join(".")
["byteback." + suffix].each do |name|
[Resolv::DNS::Resource::IN::AAAA,
Resolv::DNS::Resource::IN::A].each do |record_type|
next if !guesses.empty? # only care about first result
guesses += dns.getresources(name, record_type)
end
end
end
if guesses.empty?
error "Couldn't guess at backup host, please specify --destination"
end
# ick, do I really have to do this to get a string represnetion of
# the IP address?
#
guess = guesses.first.inspect
match = / (.*)>$/.match(guess)[1]
error "Result #{guesses} is not an IP" if !match
@destination = "byteback@#{match[1]}:#{HOSTNAME}/current/"
verbose "Guessed destination=#{@destination} from #{guess}"
end
# Test ssh connection is good before we start
#
error("Could not read ssh key #{@ssh_key}") unless File.readable?(@ssh_key)
def ssh(*args)
["ssh",
"-o", "BatchMode=yes",
"-x", "-a",
"-i", @ssh_key,
"-l", @destination_user
] +
args
end
error("Could not connect to #{@destination}") unless
system(*ssh("byteback-receive", "--ping", @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 = [
"rsync",
"--archive",
"--numeric-ids",
"--delete",
"--inplace",
"--rsync-path",
"rsync --fake-super",
"--rsh",
ssh.join(" "),
"--delete",
"--one-file-system",
"--relative"
]
args << "--verbose" if @verbose
args += @exclude.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
system(*ssh("sudo", "byteback-snapshot", "--snapshot", @verbose))
|
