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) 
16) printer_lock = threading.Lock()
17) 
18) def pinger(host, delay):
19)     """Independent worker thread: repeatedly ping, check, print and sleep."""
20)     last_results = None
21)     while True:
22)         now = time.localtime()
23)         success = ping(host)
24)         if success != last_results:
25)             status = "UP" if success else "DOWN"
26)             log(f'{time.strftime("%Y-%m-%d %H:%M:%S", now)} {host} {status}')
27)             last_results = success
28)         time.sleep(delay)
29) 
30) 
31) def ping(host):
32)     """Returns True if host (str) responds to a ping request."""
33)     return subprocess.call([*_ping_cmd, host], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL) == 0
34) 
35) 
36) def log(*args, **kwargs):
37)     """Opens the logfile, writes the log, and closes the logfile."""
38)     # I don't leave the log file open for writing because another process needs access too.
39)     with printer_lock:
40)         with open(_logname, 'a') as fp:
41)             return print(*args, **kwargs, file=fp)
42) 
43) 
44) if __name__ == '__main__':
45)     parser = ArgumentParser(description="Repeatedly ping sites. Ex: %(prog)s -d 3 192.168.1.1 192.168.1.12")
46)     parser.add_argument('-d', '--delay', type=float, default=1.0, help='Delay between pings')
47)     parser.add_argument('addresses', nargs='+', help='Addresses to ping')
48)     parser_args = parser.parse_args()
49) 
50)     _logname = os.path.join(os.path.expanduser('~'), 'log', os.path.basename(sys.argv[0]).replace('py', 'txt'))
51) 
52)     # Choose the ping parameters appropriate for the platform
53)     if sys.platform == 'cygwin' or sys.platform == 'win32':
54)         _ping_cmd = ('ping', '-n', '1', '-w', '2000')
55)     else:
56)         _ping_cmd = ('ping', '-c', '1', '-W', '2', '-q')
57) 
58)     log(f'{time.strftime("%Y-%m-%d %H:%M:%S", time.localtime())}'
59)         f' PID={os.getpid()} repeat={parser_args.delay}s Starting')

60) 
61)     # Create worker threads for all but one host address. (Saving one address for this thread.)
62)     for address in parser_args.addresses[:-1]:

63)         t = threading.Thread(target=pinger, args=(address, parser_args.delay), daemon=True)
64)         t.start()

65)         del t

66)