Module: ActsAsFerret::Remote::UnixDaemon

Included in:
Server
Defined in:
lib/unix_daemon.rb

Overview

methods for becoming a daemon on Unix-like operating systems

Instance Method Summary collapse

Instance Method Details

#ensure_stopped ⇒ Object 



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# File 'lib/unix_daemon.rb', line 63

def ensure_stopped
  if pid = read_pid_file
    if process_exists(pid)
      raise "ferret_server may already be running, a pid file exists: #{@cfg.pid_file} and a ferret_server process exists with matching pid #{pid}"
    else
      $stdout.puts("removing stale pid file...")
      File.unlink(@cfg.pid_file) if File.exist?(@cfg.pid_file)
    end
  end
end

#platform_daemon(&block) ⇒ Object 



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# File 'lib/unix_daemon.rb', line 10

def platform_daemon (&block)
  safefork do
    write_pid_file
    trap("TERM") { exit(0) }
    sess_id = Process.setsid
    STDIN.reopen("/dev/null")
    STDOUT.reopen("#{RAILS_ROOT}/log/ferret_server.out", "a")
    STDERR.reopen(STDOUT)
    block.call
  end
end

#process_exists(pid) ⇒ Object

Check for existence of ferret_server process with PID from pid file checked on ubuntu and OSX only



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# File 'lib/unix_daemon.rb', line 77

def process_exists(pid)
  ps = IO.popen("ps -fp #{pid}", "r")
  process = ps.to_a[1]
  ps.close
  process =~ /ferret_server/
end

#read_pid_file ⇒ Object 



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# File 'lib/unix_daemon.rb', line 58

def read_pid_file
  File.read(@cfg.pid_file).to_i if File.exist?(@cfg.pid_file)
end

#safefork(&block) ⇒ Object 



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# File 'lib/unix_daemon.rb', line 39

def safefork (&block)
  @fork_tries ||= 0
  fork(&block)
rescue Errno::EWOULDBLOCK
  raise if @fork_tries >= 20
  @fork_tries += 1
  sleep 5
  retry
end

#stop ⇒ Object

stop the daemon, nicely at first, and then forcefully if necessary



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# File 'lib/unix_daemon.rb', line 24

def stop
  pid = read_pid_file
  raise "ferret_server doesn't appear to be running" unless pid
  $stdout.puts("stopping ferret server...")
  Process.kill("TERM", pid)
  30.times { Process.kill(0, pid); sleep(0.5) }
  $stdout.puts("using kill -9 #{pid}")
  Process.kill(9, pid)
rescue Errno::ESRCH => e
  $stdout.puts("process #{pid} has stopped")
ensure
  File.unlink(@cfg.pid_file) if File.exist?(@cfg.pid_file)
end

#write_pid_file ⇒ Object

create the PID file and install an at_exit handler



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# File 'lib/unix_daemon.rb', line 51

def write_pid_file
  ensure_stopped
  open(@cfg.pid_file, "w") {|f| f << Process.pid << "\n"}
  at_exit { File.unlink(@cfg.pid_file) if read_pid_file == Process.pid }
end