python_pinger.git

1) #!/usr/bin/python3
2) #
3) # Since this is meant to be run as a daemon, do not use #!/usr/bin/env python3,
4) # because the process name would then be python3, not based on __FILE__.
5) #
6) # [filename] -d 3 192.168.1.1 192.168.1.12 &
7) # disown [jobid]
8) import os
9) import sys
10) import subprocess
11) import time
12) from argparse import ArgumentParser
13) import threading
14) import queue

15) import signal
16) 
17) 

18) def log_exit(sig: int, frame) -> None:

19)     _print_queue.put([f'{time.strftime("%Y-%m-%d %H:%M:%S", time.localtime())} '
20)                       f'PID={os.getpid()} signal={signal.Signals(sig).name} Exiting.'])

21)     _print_queue.join()
22)     sys.exit(0)

23) 
24) 

25) def pinger(host: str, delay: float) -> None:

26)     """Independent worker thread: repeatedly ping, check, print and sleep."""
27)     last_results = None
28)     while True:
29)         now = time.localtime()
30)         success = ping(host)
31)         if success != last_results:
32)             status = "UP" if success else "DOWN"
33)             _print_queue.put([f'{time.strftime("%Y-%m-%d %H:%M:%S", now)} {host} {status}'])
34)             last_results = success
35)         time.sleep(delay)
36) 
37) 

38) def ping(host: str) -> int:

39)     """Returns True if host (str) responds to a ping request."""
40)     return subprocess.call([*_ping_cmd, host], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL) == 0
41) 
42) 

43) def print_manager() -> None:

44)     """The only thread allowed to write output."""
45)     while True:
46)         job = _print_queue.get()
47)         for line in job:
48)             log(line)
49)         _print_queue.task_done()
50) 
51) 

52) def log(*args, **kwargs) -> None:

53)     """Opens the logfile, writes the log, and closes the logfile."""
54)     # I don't leave the log file open for writing because another process needs access too.
55)     with open(_logname, 'a') as fp:

56)         print(*args, **kwargs, file=fp)

57) 
58) 
59) if __name__ == '__main__':
60)     parser = ArgumentParser(description="Repeatedly ping sites. Ex: %(prog)s -d 3 192.168.1.1 192.168.1.12")

61)     parser.add_argument('-d', '--delay', type=float, default=3.0, help='Delay between pings')

62)     parser.add_argument('addresses', nargs='+', help='Addresses to ping')
63)     parser_args = parser.parse_args()
64) 
65)     _logname = os.path.join(os.path.expanduser('~'), 'log', os.path.basename(sys.argv[0]).replace('py', 'txt'))
66) 
67)     # Choose the ping parameters appropriate for the platform
68)     if sys.platform == 'cygwin' or sys.platform == 'win32':
69)         _ping_cmd = ('ping', '-n', '1', '-w', '2000')
70)     else:
71)         _ping_cmd = ('ping', '-c', '1', '-W', '2', '-q')
72) 
73)     _print_queue = queue.Queue()
74)     print_thread = threading.Thread(target=print_manager, daemon=True)
75)     print_thread.start()
76) 

77)     _print_queue.put([f'{time.strftime("%Y-%m-%d %H:%M:%S", time.localtime())} PID={os.getpid()}'
78)         f' repeat={parser_args.delay}s addresses={",".join(parser_args.addresses)} Starting'])
79) 
80)     signal.signal(signal.SIGINT, log_exit)
81)     signal.signal(signal.SIGTERM, log_exit)

82) 
83)     # Create worker threads for all but one host address. (Saving one address for this thread.)
84)     for address in parser_args.addresses[:-1]:

85)         t = threading.Thread(target=pinger, args=(address, parser_args.delay), daemon=True)
86)         t.start()
87)         del t
88)