summaryrefslogtreecommitdiff
path: root/byteback-backup
blob: 8595eb156df3f6769f6d770c0af57677ee3d6e77 (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
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
#!/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 remove_lockfile!
  begin
    File.unlink(@lockfile)
  rescue Errno::ENOENT
  end
end

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 (default: /)
       --exclude, -x <s>:   Exclude paths (defaults: /swap.file, /var/backups/localhost, /var/cache/apt/archives, /var/lib/php5, /tmp, /var/tmp)
           --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

Additional excludes can be specified using /etc/byteback/rsync_filter, which is
an rsync filter file.  See the rsync man page for information on how this
works.

EOF
  remove_lockfile!
  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
@lockfile = "/var/run/byteback/byteback.lock"


# 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

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 the lockfile first
if File.directory?(File.dirname(@lockfile))
  if File.exists? @lockfile
    # check the lockfile is sane
    exist_pid = File.read(@lockfile).to_i
    if exist_pid > 1 and exist_pid < (File.read("/proc/sys/kernel/pid_max").to_i)
      begin
        Process.getpgid(exist_pid)
        # if no exception, process is running, abort
        error("Process is running (#{exist_pid} from #{@lockfile})! Exiting now.")
      rescue Errno::ESRCH
        # no process running with that pid, pidfile is stale
        remove_lockfile!
      end
    else
      # lockfile isn't sane, remove it and continue
      remove_lockfile!
    end
  end
else
  Dir.mkdir(File.dirname(@lockfile))
  # lockfile didn't exist so just carry on
end

# Own the pidfile ourselves
File.open(@lockfile, "w") do |lockfile|
  lockfile.puts Process::pid
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 = %w(
     /swap.file
     /tmp
     /var/backups/localhost
     /var/cache/apt/archives
     /var/lib/php5
     /var/tmp
  ).select do |x|
    File.exists?(x)
  end
end


#
# Always add these filesystems
#
@excludes += %w(/dev /proc /run /sys)

@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-delay --inplace --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

  #
  # Add in the rsync excludes and sources files, if present.
  #
  if File.exists?("/etc/byteback/excludes")
      args += ["--exclude-from", "/etc/byteback/excludes"]
  end

  #
  # Add in an rsync_filter if required.
  #
  if File.exists?("/etc/byteback/rsync_filter")
      args += ["--filter", "merge /etc/byteback/rsync_filter"]
  end

  args += sources
  args << @destination

  print args.map { |a| / /.match(a) ? "\"#{a}\"" : a }.join(" ")+"\n" if $VERBOSE

  system(*args)

  return $?.exitstatus
end

#
# We treat exit statuses 0 and 24 as success; 0 is "Success"; 24 is "Partial
# transfer due to vanished source files", which we treat as success otherwise
# on some hosts the backup process never finishes.
#
RSYNC_EXIT_STATUSES_TO_ACCEPT   = [0, 24]
RSYNC_EXIT_STATUSES_TO_RETRY_ON = [10,11,20,21,22,23,30]

# Run the file copy, retrying if necessary
#
loop do
  status = rsync(*@sources)

  if RSYNC_EXIT_STATUSES_TO_ACCEPT.any?{|s| s === status} 
    break
  elsif RSYNC_EXIT_STATUSES_TO_RETRY_ON.any?{|s| s === 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" : ""))

remove_lockfile!