Class: Daemons::Application

Inherits:
Object
  • Object
show all
Defined in:
lib/daemons/application.rb

Constant Summary collapse

SIGNAL = 
(RUBY_PLATFORM =~ /win32/ ? 'KILL' : 'TERM')

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(group, add_options = {}, pid = nil) ⇒ Application

Returns a new instance of Application.



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
 
# File 'lib/daemons/application.rb', line 26

def initialize(group, add_options = {}, pid = nil)
  @group = group
  @options = group.options.dup
  @options.update(add_options)

  ['dir', 'log_dir', 'logfilename', 'output_logfilename'].each do |k|
    @options[k] = File.expand_path(@options[k]) if @options.key?(k)
  end

  @dir_mode = @dir = @script = nil

  @force_kill_waittime = @options[:force_kill_waittime] || 20

  @signals_and_waits = parse_signals_and_waits(@options[:signals_and_waits])

  @show_status_callback = method(:default_show_status)

  @report = Reporter.new(@options)

  unless @pid = pid
    if @options[:no_pidfiles]
      @pid = PidMem.new
    elsif dir = pidfile_dir
      @pid = PidFile.new(dir, @group.app_name, @group.multiple, @options[:pid_delimiter])
    else
      @pid = PidMem.new
    end
  end
end

Instance Attribute Details

#app_argv ⇒ Object

Returns the value of attribute app_argv.



12
13
14
 
# File 'lib/daemons/application.rb', line 12

def app_argv
  @app_argv
end

#controller_argv ⇒ Object

Returns the value of attribute controller_argv.



13
14
15
 
# File 'lib/daemons/application.rb', line 13

def controller_argv
  @controller_argv
end

#group ⇒ Object (readonly)

the ApplicationGroup the application belongs to



19
20
21
 
# File 'lib/daemons/application.rb', line 19

def group
  @group
end

#options ⇒ Object (readonly)

my private options



22
23
24
 
# File 'lib/daemons/application.rb', line 22

def options
  @options
end

#pid ⇒ Object (readonly)

the Pid instance belonging to this application



16
17
18
 
# File 'lib/daemons/application.rb', line 16

def pid
  @pid
end

Instance Method Details

#change_privilege ⇒ Object 



65
66
67
68
69
70
71
72
 
# File 'lib/daemons/application.rb', line 65

def change_privilege
  user = options[:user]
  group = options[:group]
  if user
    @report.changing_process_privilege(user, group)
    CurrentProcess.change_privilege(user, group)
  end
end

#default_show_status(daemon = self) ⇒ Object 



438
439
440
441
442
 
# File 'lib/daemons/application.rb', line 438

def default_show_status(daemon = self)
  running = daemon.running?

  @report.status(group.app_name, running, daemon.pid.exist?, daemon.pid.pid.to_s)
end

#exception_log ⇒ Object

This is a nice little function for debugging purposes: In case a multi-threaded ruby script exits due to an uncaught exception it may be difficult to find out where the exception came from because one cannot catch exceptions that are thrown in threads other than the main thread.

This function searches for all exceptions in memory and outputs them to $stderr (if it is connected) and to a log file in the pid-file directory.



341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
 
# File 'lib/daemons/application.rb', line 341

def exception_log
  return unless logfile

  require 'logger'

  l_file = Logger.new(logfile)

  # the code below finds the last exception
  e = nil

  ObjectSpace.each_object do |o|
    if ::Exception === o
      e = o
    end
  end

  l_file.info '*** below you find the most recent exception thrown, this will be likely (but not certainly) the exception that made the application exit abnormally ***'
  l_file.error e

  l_file.info '*** below you find all exception objects found in memory, some of them may have been thrown in your application, others may just be in memory because they are standard exceptions ***'

  # this code logs every exception found in memory
  ObjectSpace.each_object do |o|
    if ::Exception === o
      l_file.error o
    end
  end

  l_file.close
end

#logdir ⇒ Object 



82
83
84
85
 
# File 'lib/daemons/application.rb', line 82

def logdir
  options[:log_dir] or
    options[:dir_mode] == :system ? '/var/log' : pidfile_dir
end

#logfile ⇒ Object 



103
104
105
106
107
 
# File 'lib/daemons/application.rb', line 103

def logfile
  if logdir
    File.join logdir, logfilename
  end
end

#logfilename ⇒ Object 



99
100
101
 
# File 'lib/daemons/application.rb', line 99

def logfilename
  options[:logfilename] or "#{@group.app_name}.log"
end

#output_logfile ⇒ Object 



91
92
93
94
95
96
97
 
# File 'lib/daemons/application.rb', line 91

def output_logfile
  if log_output_syslog?
    'SYSLOG'
  elsif log_output?
    File.join logdir, output_logfilename
  end
end

#output_logfilename ⇒ Object 



87
88
89
 
# File 'lib/daemons/application.rb', line 87

def output_logfilename
  options[:output_logfilename] or "#{@group.app_name}.output"
end

#pidfile_dir ⇒ Object 



78
79
80
 
# File 'lib/daemons/application.rb', line 78

def pidfile_dir
  Pid.dir dir_mode, dir, script
end

#reload ⇒ Object 



319
320
321
322
323
324
325
326
327
328
329
330
 
# File 'lib/daemons/application.rb', line 319

def reload
  if @pid.pid == 0
    zap
    start
  else
    begin
      Process.kill('HUP', @pid.pid)
    rescue
      # ignore
    end
  end
end

#running? ⇒ Boolean

This function implements a (probably too simle) method to detect whether the program with the pid found in the pid-file is still running. It just searches for the pid in the output of ps ax, which is probably not a good idea in some cases. Alternatives would be to use a direct access method the unix process control system.

Returns:

  • (Boolean) 


451
452
453
 
# File 'lib/daemons/application.rb', line 451

def running?
  @pid.exist? and Pid.running? @pid.pid
end

#script ⇒ Object 



74
75
76
 
# File 'lib/daemons/application.rb', line 74

def script
  @script or group.script
end

#show_status ⇒ Object 



434
435
436
 
# File 'lib/daemons/application.rb', line 434

def show_status
  @show_status_callback.call(self)
end

#show_status_callback=(function) ⇒ Object 



56
57
58
59
60
61
62
63
 
# File 'lib/daemons/application.rb', line 56

def show_status_callback=(function)
  @show_status_callback =
    if function.respond_to?(:call)
      function
    else
      method(function)
    end
end

#start(restart = false) ⇒ Object 



291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
 
# File 'lib/daemons/application.rb', line 291

def start(restart = false)
  change_privilege

  unless restart
    @group.create_monitor(self) unless options[:ontop]  # we don't monitor applications in the foreground
  end

  case options[:mode]
    when :none
      # this is only used to daemonize the currently running process
      start_none
    when :exec
      start_exec
    when :load
      start_load
    when :proc
      start_proc
    else
      start_load
  end
end

#start_exec ⇒ Object 



152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
 
# File 'lib/daemons/application.rb', line 152

def start_exec
  if options[:backtrace]
    @report.backtrace_not_supported
  end

  unless options[:ontop]
    Daemonize.daemonize(output_logfile, @group.app_name)
  else
    Daemonize.simulate(output_logfile)
  end

  # note that we cannot remove the pid file if we run in :ontop mode (i.e. 'ruby ctrl_exec.rb run')
  @pid.pid = Process.pid

  ENV['DAEMONS_ARGV'] = @controller_argv.join(' ')

  started
  Kernel.exec(script, *(@app_argv || []))
end

#start_load ⇒ Object 



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
 
# File 'lib/daemons/application.rb', line 172

def start_load
  unless options[:ontop]
    Daemonize.daemonize(output_logfile, @group.app_name)
  else
    Daemonize.simulate(output_logfile)
  end

  @pid.pid = Process.pid

  # We need this to remove the pid-file if the applications exits by itself.
  # Note that <tt>at_exit</tt> will only be run if the applications exits by calling
  # <tt>exit</tt>, and not if it calls <tt>exit!</tt> (so please don't call <tt>exit!</tt>
  # in your application!
  #
  at_exit do
    begin; @pid.cleanup; rescue ::Exception; end

    # If the option <tt>:backtrace</tt> is used and the application did exit by itself
    # create a exception log.
    if options[:backtrace] && !options[:ontop] && !$daemons_sigterm
      begin; exception_log; rescue ::Exception; end
    end

  end

  # This part is needed to remove the pid-file if the application is killed by
  # daemons or manually by the user.
  # Note that the applications is not supposed to overwrite the signal handler for
  # 'TERM'.
  #
  $daemons_stop_proc = options[:stop_proc]
  trap(SIGNAL) do
    begin
      if $daemons_stop_proc
        $daemons_stop_proc.call
      end
    rescue ::Exception
    end

    begin; @pid.cleanup; rescue ::Exception; end
    $daemons_sigterm = true

    if options[:hard_exit]
      exit!
    else
      exit
    end
  end

  # Now we really start the script...
  $DAEMONS_ARGV = @controller_argv
  ENV['DAEMONS_ARGV'] = @controller_argv.join(' ')

  ARGV.clear
  ARGV.concat @app_argv if @app_argv

  started
  # TODO: exception logging
  load script
end

#start_none ⇒ Object

this function is only used to daemonize the currently running process (Daemons.daemonize)



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
 
# File 'lib/daemons/application.rb', line 110

def start_none
  unless options[:ontop]
    Daemonize.daemonize(output_logfile, @group.app_name)
  else
    Daemonize.simulate(output_logfile)
  end

  @pid.pid = Process.pid

  # We need this to remove the pid-file if the applications exits by itself.
  # Note that <tt>at_text</tt> will only be run if the applications exits by calling
  # <tt>exit</tt>, and not if it calls <tt>exit!</tt> (so please don't call <tt>exit!</tt>
  # in your application!
  #
  at_exit do
    begin; @pid.cleanup; rescue ::Exception; end

    # If the option <tt>:backtrace</tt> is used and the application did exit by itself
    # create a exception log.
    if options[:backtrace] && !options[:ontop] && !$daemons_sigterm
      begin; exception_log; rescue ::Exception; end
    end

  end

  # This part is needed to remove the pid-file if the application is killed by
  # daemons or manually by the user.
  # Note that the applications is not supposed to overwrite the signal handler for
  # 'TERM'.
  #
  trap(SIGNAL) do
    begin; @pid.cleanup; rescue ::Exception; end
    $daemons_sigterm = true

    if options[:hard_exit]
      exit!
    else
      exit
    end
  end
end

#start_proc ⇒ Object 



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
284
285
286
287
288
289
 
# File 'lib/daemons/application.rb', line 233

def start_proc
  return unless p = options[:proc]

  myproc = proc do

    # We need this to remove the pid-file if the applications exits by itself.
    # Note that <tt>at_text</tt> will only be run if the applications exits by calling
    # <tt>exit</tt>, and not if it calls <tt>exit!</tt> (so please don't call <tt>exit!</tt>
    # in your application!
    #
    at_exit do
      begin; @pid.cleanup; rescue ::Exception; end

      # If the option <tt>:backtrace</tt> is used and the application did exit by itself
      # create a exception log.
      if options[:backtrace] && !options[:ontop] && !$daemons_sigterm
        begin; exception_log; rescue ::Exception; end
      end

    end

    # This part is needed to remove the pid-file if the application is killed by
    # daemons or manually by the user.
    # Note that the applications is not supposed to overwrite the signal handler for
    # 'TERM'.
    #
    $daemons_stop_proc = options[:stop_proc]
    trap(SIGNAL) do
      begin
        if $daemons_stop_proc
          $daemons_stop_proc.call
        end
      rescue ::Exception
      end

      begin; @pid.cleanup; rescue ::Exception; end
      $daemons_sigterm = true

      if options[:hard_exit]
        exit!
      else
        exit
      end
    end
    p.call
  end

  unless options[:ontop]
    @pid.pid = Daemonize.call_as_daemon(myproc, output_logfile, @group.app_name)

  else
    Daemonize.simulate(output_logfile)

    myproc.call
  end
  started
end

#started ⇒ Object 



313
314
315
316
317
 
# File 'lib/daemons/application.rb', line 313

def started
  if pid = @pid.pid
    @report.process_started(group.app_name, pid)
  end
end

#stop(no_wait = false) ⇒ Object 



372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
 
# File 'lib/daemons/application.rb', line 372

def stop(no_wait = false)
  unless running?
    zap
    return
  end

  # confusing: pid is also a attribute_reader
  pid = @pid.pid

  # Catch errors when trying to kill a process that doesn't
  # exist. This happens when the process quits and hasn't been
  # restarted by the monitor yet. By catching the error, we allow the
  # pid file clean-up to occur.
  begin
    wait_and_retry_kill_harder(pid, @signals_and_waits, no_wait)
  rescue Errno::ESRCH => e
    @report.output_message("#{e} #{pid}")
    @report.output_message('deleting pid-file.')
  end

  sleep(0.1)
  unless Pid.running?(pid)
    # We try to remove the pid-files by ourselves, in case the application
    # didn't clean it up.
    zap!

    @report.stopped_process(group.app_name, pid)
  end
end

#wait_and_retry_kill_harder(pid, remaining_signals, no_wait = false) ⇒ Object

Parameters:

  • Hash —

    remaing_signals

  • Boolean —

    no_wait Send first Signal and return



404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
 
# File 'lib/daemons/application.rb', line 404

def wait_and_retry_kill_harder(pid, remaining_signals, no_wait = false)
  sig_wait = remaining_signals.shift
  sig      = sig_wait[:sig]
  wait     = sig_wait[:wait]
  Process.kill(sig, pid)
  return if no_wait || !wait.positive?

  @report.stopping_process(group.app_name, pid, sig, wait)

  begin
    Timeout.timeout(wait, TimeoutError) do
      sleep(0.2) while Pid.running?(pid)
    end
  rescue TimeoutError
    if remaining_signals.any?
      wait_and_retry_kill_harder(pid, remaining_signals)
    else
      @report.cannot_stop_process(group.app_name, pid)
    end
  end
end

#zap ⇒ Object 



426
427
428
 
# File 'lib/daemons/application.rb', line 426

def zap
  @pid.zap
end

#zap! ⇒ Object 



430
431
432
 
# File 'lib/daemons/application.rb', line 430

def zap!
  begin; @pid.zap; rescue ::Exception; end
end