libtuer.py

   1 import logging, logging.handlers, os, time, queue, threading, subprocess
   2
   3 # logging function
   4 class Logger:
   5         def __init__ (self):
   6                 import __main__ as main
   7                 self.name = os.path.basename(main.__file__)
   8                 self.logger = logging.getLogger(self.name)
   9                 self.logger.setLevel(logging.INFO)
  10                 self.handler = logging.handlers.SysLogHandler(address = '/dev/log', facility = logging.handlers.SysLogHandler.LOG_LOCAL0)
  11                 self.logger.addHandler(self.handler)
  12
  13         def log (self, lvl, what):
  14                 thestr = "%s[%d]: %s" % (self.name,os.getpid(),what)
  15                 print (thestr)
  16                 self.logger.log(lvl, thestr)
  17
  18         def debug(self, what):
  19                 self.log(logging.DEBUG, what)
  20         def info(self, what):
  21                 self.log(logging.INFO, what)
  22         def warning(self, what):
  23                 self.log(logging.WARNING, what)
  24         def error(self, what):
  25                 self.log(logging.ERROR, what)
  26         def critical(self, what):
  27                 self.log(logging.CRITICAL, what)
  28
  29 logger = Logger()
  30
  31 # run a command asynchronously and log the return value if not 0
  32 # prefix must be a string identifying the code position where the call came from
  33 def fire_and_forget (cmd, log, prefix):
  34         def _fire_and_forget ():
  35                 with open("/dev/null", "w") as fnull:
  36                         retcode = subprocess.call(cmd, stdout=fnull, stderr=fnull)
  37                         if retcode is not 0:
  38                                 log("%sReturn code %d at command: %s" % (prefix,retcode,str(cmd)))
  39         t = threading.Thread(target=_fire_and_forget)
  40         t.start()
  41
  42 # Threaded callback class
  43 class ThreadFunction():
  44         _CALL = 0
  45         _TERM = 1
  46
  47         def __init__(self, f):
  48                 self._f = f
  49                 self._q = queue.Queue()
  50                 self._t = threading.Thread(target=self._thread_func)
  51                 self._t.start()
  52
  53         def _thread_func(self):
  54                 while True:
  55                         (cmd, data) = self._q.get()
  56                         # run command
  57                         if cmd == _CALL:
  58                                 try:
  59                                         self._f(*data)
  60                                 except Exception:
  61                                         logger.error("ThreadFunction: Got exception out of handler thread: %s" % str(e))
  62                         elif cmd == _TERM:
  63                                 assert data is None
  64                                 break
  65                         else:
  66                                 logger.error("ThreadFunction: Command %d does not exist" % cmd)
  67
  68         def __call__(self, *arg):
  69                 self._q.put((self._CALL, arg))
  70
  71         def stop(self):
  72                 self._q.put((_TERM, None))
  73                 self._t.join()
  74
  75 # Thread timer-repeater class: Call a function every <sleep_time> seconds
  76 class ThreadRepeater():
  77         def __init__(self, f, sleep_time):
  78                 self._f = f
  79                 self._stop = False
  80                 self._sleep_time = sleep_time
  81                 self._t = threading.Thread(target=self._thread_func)
  82                 self._t.start()
  83
  84         def _thread_func():
  85                 while True:
  86                         if self._stop:
  87                                 break
  88                         self._f()
  89                         time.sleep(sleep_time)
  90
  91         def stop(self):
  92                 self._stop = True
  93                 self._t.join()