Question

I have a python script that I want always to run in the background. What the application does is that it goes to a Oracle database and checks if there is a message to be displayed to the user and if there is, use the pynotify to display a notification.

I tried using a Timer object but it only invoke the method after the selective time. I want it to invoke every time after the selective time.

if __name__ == '__main__':
  applicationName = "WEWE"
    # Initialization of the Notification library
  if not pynotify.init(applicationName):
   sys.exit(1)         

  t = threading.Timer(5.0, runWorks)
  t.start() 

Will doing this work and is there a better way?

 if __name__ == '__main__':
      applicationName = "WEEWRS"
        # Initialization of the Notification library
      if not pynotify.init(applicationName):
       sys.exit(1)         
      while True:
       t = threading.Timer(5.0, runWorks)
       t.start() 

But that gave me another problem.

thread.error: can't start new thread

(r.py:12227): GLib-ERROR **: creating thread 'gdbus': Error creating thread: Resource temporarily unavailable

Answer 1

I solved the problem reducing the creation of strings. The below error –

thread.error: can't start new thread

(r.py:12227): GLib-ERROR **: creating thread 'gdbus': Error creating thread: Resource temporarily unavailable

comes when there is a lack of resources. Below is the corrected code.

if __name__ == '__main__':
  applicationName = "DSS POS"
  # Initialization of the Notification library
  if not pynotify.init(applicationName):
   sys.exit(1)         

  flagContinous = True
  timeout = 5
  # This loop will continously keep the application in the background
  while flagContinous:
   time.sleep(timeout)
   runWorks()
  # After 30 seconds, "hello, world" will be printed  

I also used a lock file so that the script won’t run multiple-times.

pid = str(os.getpid())
  pidfile = "/tmp/mydaemon.pid"

  # If we have a lock already block the program
  if os.path.isfile(pidfile):
    print "%s already exists, exiting" % pidfile
    sys.exit()
  else:
    file(pidfile, 'w').write(pid)
  # Do all the work
  applicationName = "DSS POS"
  # Initialization of the Notification library
  if not pynotify.init(applicationName):
   sys.exit(1)         

  # Controls for the application
  flagContinous = True
  timeout = 5
  # This loop will continously keep the application in the background
  while flagContinous:
   time.sleep(timeout)
   runWorks()
  # After 30 seconds, "hello, world" will be printed  

  # Release the file
  os.unlink(pidfile)