lantz
cf5675876c
1. update/fix codecheck Run workflow with pylint 2.15.7 Add a bunch of fiddly and mostly cosmetic changes to make pylint (and make codecheck) happy. Also try to run pyflakes3 vs. pyflakes 2. remove Ubuntu 18.04 Ubuntu 18.04 has been removed from github actions, so we remove it from our workflow as well
86 lines
2.6 KiB
Python
Executable File
86 lines
2.6 KiB
Python
Executable File
#!/usr/bin/env python
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"""
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Simple example of sending output to multiple files and
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monitoring them
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"""
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from time import time
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from select import poll, POLLIN
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from subprocess import Popen, PIPE
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from mininet.topo import SingleSwitchTopo
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from mininet.net import Mininet
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from mininet.log import info, setLogLevel
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from mininet.util import decode
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def monitorFiles( outfiles, seconds, timeoutms ):
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"Monitor set of files and return [(host, line)...]"
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devnull = open( '/dev/null', 'w' ) # pylint: disable=consider-using-with
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tails, fdToFile, fdToHost = {}, {}, {}
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for h, outfile in outfiles.items():
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tail = Popen( # pylint: disable=consider-using-with
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[ 'tail', '-f', outfile ],
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stdout=PIPE, stderr=devnull )
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fd = tail.stdout.fileno()
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tails[ h ] = tail
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fdToFile[ fd ] = tail.stdout
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fdToHost[ fd ] = h
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# Prepare to poll output files
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readable = poll()
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for t in tails.values():
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readable.register( t.stdout.fileno(), POLLIN )
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# Run until a set number of seconds have elapsed
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endTime = time() + seconds
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while time() < endTime:
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fdlist = readable.poll(timeoutms)
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if fdlist:
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for fd, _flags in fdlist:
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f = fdToFile[ fd ]
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host = fdToHost[ fd ]
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# Wait for a line of output
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line = f.readline().strip()
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yield host, decode( line )
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else:
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# If we timed out, return nothing
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yield None, ''
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for t in tails.values():
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t.terminate()
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devnull.close() # Not really necessary
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def monitorTest( N=3, seconds=3 ):
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"Run pings and monitor multiple hosts"
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topo = SingleSwitchTopo( N )
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net = Mininet( topo, waitConnected=True )
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net.start()
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hosts = net.hosts
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info( "Starting test...\n" )
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server = hosts[ 0 ]
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outfiles, errfiles = {}, {}
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for h in hosts:
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# Create and/or erase output files
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outfiles[ h ] = '/tmp/%s.out' % h.name
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errfiles[ h ] = '/tmp/%s.err' % h.name
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h.cmd( 'echo >', outfiles[ h ] )
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h.cmd( 'echo >', errfiles[ h ] )
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# Start pings
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h.cmdPrint('ping', server.IP(),
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'>', outfiles[ h ],
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'2>', errfiles[ h ],
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'&' )
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info( "Monitoring output for", seconds, "seconds\n" )
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for h, line in monitorFiles( outfiles, seconds, timeoutms=500 ):
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if h:
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info( '%s: %s\n' % ( h.name, line ) )
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for h in hosts:
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h.cmd('kill %ping')
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net.stop()
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if __name__ == '__main__':
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setLogLevel('info')
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monitorTest()
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