Class: Katello::EventDaemon::Runner

Inherits:
Object
  • Object
show all
Defined in:
app/lib/katello/event_daemon/runner.rb

Constant Summary collapse

STATUS_CACHE_KEY = 
"katello_event_daemon_status".freeze

Class Method Summary collapse

Class Method Details

.lock_file ⇒ Object 



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# File 'app/lib/katello/event_daemon/runner.rb', line 33

def lock_file
  tmp_dir.join('katello_event_daemon.lock')
end

.pid ⇒ Object 



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# File 'app/lib/katello/event_daemon/runner.rb', line 13

def pid
  return unless pid_file

  File.read(pid_file)&.to_i
rescue Errno::ENOENT
  nil
end

.pid_dir ⇒ Object 



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# File 'app/lib/katello/event_daemon/runner.rb', line 29

def pid_dir
  tmp_dir.join('pids')
end

.pid_file ⇒ Object 



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# File 'app/lib/katello/event_daemon/runner.rb', line 21

def pid_file
  pid_dir.join('katello_event_daemon.pid')
end

.register_service(name, klass) ⇒ Object 



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# File 'app/lib/katello/event_daemon/runner.rb', line 96

def register_service(name, klass)
  @services[name] = klass
end

.runnable? ⇒ Boolean 



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# File 'app/lib/katello/event_daemon/runner.rb', line 89

def runnable?
  # avoid accessing the disk on each request
  @cache.fetch('katello_event_daemon_runnable', expires_in: 1.minute) do
    !started? && settings[:enabled] && !::Foreman.in_rake? && !Rails.env.test?
  end
end

.service_status(service_name = nil) ⇒ Object 



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# File 'app/lib/katello/event_daemon/runner.rb', line 100

def service_status(service_name = nil)
  Rails.cache.read(STATUS_CACHE_KEY)&.dig(service_name)
end

.settings ⇒ Object 



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# File 'app/lib/katello/event_daemon/runner.rb', line 9

def settings
  SETTINGS[:katello][:event_daemon]
end

.start ⇒ Object 



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# File 'app/lib/katello/event_daemon/runner.rb', line 52

def start
  return unless runnable?

  FileUtils.mkdir_p(tmp_dir)
  FileUtils.touch(lock_file)

  File.open(lock_file, 'r') do |lockfile|
    lockfile.flock(File::LOCK_EX)
    return nil if started? # ensure it wasn't started while we waited for the lock
    start_monitor_thread
    write_pid_file

    at_exit do
      stop
    end

    Rails.logger.info("Katello event daemon started process=#{Process.pid}")
  ensure
    lockfile.flock(File::LOCK_UN)
  end
end

.start_monitor_thread ⇒ Object 



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# File 'app/lib/katello/event_daemon/runner.rb', line 81

def start_monitor_thread
  @monitor_thread = Thread.new do
    Rails.application.executor.wrap do
      Katello::EventDaemon::Monitor.new(@services).start
    end
  end
end

.started? ⇒ Boolean 



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# File 'app/lib/katello/event_daemon/runner.rb', line 74

def started?
  Process.kill(0, pid)
  true
rescue Errno::ESRCH, TypeError # process no longer exists or we had no PID cached
  false
end

.stop ⇒ Object 



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# File 'app/lib/katello/event_daemon/runner.rb', line 44

def stop
  return unless pid == Process.pid
  @monitor_thread.kill
  @cache.clear
  @services.values.each(&:close)
  FileUtils.rm_f(pid_file) if pid_file
end

.tmp_dir ⇒ Object 



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# File 'app/lib/katello/event_daemon/runner.rb', line 25

def tmp_dir
  Rails.root.join('tmp')
end

.write_pid_file ⇒ Object 



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# File 'app/lib/katello/event_daemon/runner.rb', line 37

def write_pid_file
  return unless pid_file

  FileUtils.mkdir_p(pid_dir)
  File.write(pid_file, Process.pid)
end