summaryrefslogtreecommitdiff
path: root/byteback-backup
blob: ffc4186ad3284ac5c931d13edbeed9608578e86b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
#!/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))