class Daemons::Application
Constants
- SIGNAL
Attributes
the ApplicationGroup
the application belongs to
my private options
the Pid
instance belonging to this application
Public Class Methods
# 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 @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
Public Instance Methods
# File lib/daemons/application.rb, line 63 def change_privilege user = options[:user] group = options[:group] if user @report.changing_process_privilege(user, group) CurrentProcess.change_privilege(user, group) end end
# File lib/daemons/application.rb, line 447 def default_show_status(daemon = self) running = daemon.running? @report.status(group.app_name, running, daemon.pid.exist?, daemon.pid.pid.to_s) end
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.
# File lib/daemons/application.rb, line 339 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
# File lib/daemons/application.rb, line 80 def logdir options[:log_dir] or options[:dir_mode] == :system ? '/var/log' : pidfile_dir end
# File lib/daemons/application.rb, line 101 def logfile if logdir File.join logdir, logfilename end end
# File lib/daemons/application.rb, line 97 def logfilename options[:logfilename] or "#{@group.app_name}.log" end
# File lib/daemons/application.rb, line 89 def output_logfile if log_output_syslog? 'SYSLOG' elsif log_output? File.join logdir, output_logfilename end end
# File lib/daemons/application.rb, line 85 def output_logfilename options[:output_logfilename] or "#{@group.app_name}.output" end
# File lib/daemons/application.rb, line 76 def pidfile_dir Pid.dir dir_mode, dir, script end
# File lib/daemons/application.rb, line 317 def reload if @pid.pid == 0 zap start else begin Process.kill('HUP', @pid.pid) rescue # ignore end end end
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.
# File lib/daemons/application.rb, line 460 def running? @pid.exist? and Pid.running? @pid.pid end
# File lib/daemons/application.rb, line 72 def script @script or group.script end
# File lib/daemons/application.rb, line 443 def show_status @show_status_callback.call(self) end
# File lib/daemons/application.rb, line 54 def show_status_callback=(function) @show_status_callback = if function.respond_to?(:call) function else method(function) end end
# File lib/daemons/application.rb, line 289 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
# File lib/daemons/application.rb, line 150 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
# File lib/daemons/application.rb, line 170 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... $DAEMONS_ARGV = @controller_argv ENV['DAEMONS_ARGV'] = @controller_argv.join(' ') ARGV.clear ARGV.concat @app_argv if @app_argv started # TODO: exception logging load script end
this function is only used to daemonize the currently running process (Daemons.daemonize)
# File lib/daemons/application.rb, line 108 def start_none unless options[:ontop] Daemonize.daemonize(output_logfile, @group.app_name) else Daemonize.simulate(output_logfile) end @pid.pid = Process.pid # We need this to remove the pid-file if the applications exits by itself. # Note that <tt>at_text</tt> will only be run if the applications exits by calling # <tt>exit</tt>, and not if it calls <tt>exit!</tt> (so please don't call <tt>exit!</tt> # in your application! # at_exit do begin; @pid.cleanup; rescue ::Exception; end # If the option <tt>:backtrace</tt> is used and the application did exit by itself # create a exception log. if options[:backtrace] && !options[:ontop] && !$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 $daemons_sigterm = true if options[:hard_exit] exit! else exit end end end
# File lib/daemons/application.rb, line 231 def start_proc return unless p = options[:proc] myproc = proc do # We need this to remove the pid-file if the applications exits by itself. # Note that <tt>at_text</tt> will only be run if the applications exits by calling # <tt>exit</tt>, and not if it calls <tt>exit!</tt> (so please don't call <tt>exit!</tt> # in your application! # at_exit do begin; @pid.cleanup; rescue ::Exception; end # If the option <tt>:backtrace</tt> is used and the application did exit by itself # create a exception log. if options[:backtrace] && !options[:ontop] && !$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
# File lib/daemons/application.rb, line 311 def started if pid = @pid.pid @report.process_started(group.app_name, pid) end end
# File lib/daemons/application.rb, line 370 def stop(no_wait = false) unless running? zap return end 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 Process.kill(SIGNAL, pid) rescue Errno::ESRCH => e @report.output_message("#{e} #{pid}") @report.output_message('deleting pid-file.') end unless no_wait if @force_kill_waittime > 0 @report.stopping_process(group.app_name, pid) $stdout.flush begin Timeout.timeout(@force_kill_waittime, TimeoutError) do while Pid.running?(pid) sleep(0.2) end end rescue TimeoutError @report.forcefully_stopping_process(group.app_name, pid) $stdout.flush begin Process.kill('KILL', pid) rescue Errno::ESRCH end begin Timeout.timeout(20, TimeoutError) do while Pid.running?(pid) sleep(1) end end rescue TimeoutError @report.cannot_stop_process(group.app_name, pid) $stdout.flush end end end 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) $stdout.flush end end
# File lib/daemons/application.rb, line 435 def zap @pid.zap end
# File lib/daemons/application.rb, line 439 def zap! begin; @pid.zap; rescue ::Exception; end end
Private Instance Methods
# File lib/daemons/application.rb, line 478 def dir @dir or group.dir end
# File lib/daemons/application.rb, line 474 def dir_mode @dir_mode or group.dir_mode end
# File lib/daemons/application.rb, line 466 def log_output? options[:log_output] && logdir end
# File lib/daemons/application.rb, line 470 def log_output_syslog? options[:log_output_syslog] end