Files
mininet/examples/multipoll.py
T
lantz b7c412073a CI matrix build + 20.04 fixes (#990)
Ubuntu 20.04 fixes:
- fixes sshd test
- speeds up examples/{treeping64,tree1024}.py
- debugging hacks/output for testLinkChange
- removes cfs from examples/popen.py
- improves nat in nodelib (netplan fixes?)
- makes some tests executable
- waits for switches to connect in tests to
  avoid race conditions
-- adds mn -w option and wait CLI command
Changes:
- REMOVES default "-v" argument for Controller()
  and adds verbose(=False) option; avoiding logging
  makes it faster
- CHANGES waitConnected to wait for 5 seconds
  as documented; we may wish to implement an argument
  to -w to set this timeout
Issues?
- There may still be an issue with the ovs-netplan-clean
  service causing the boot to hang ;-(
2021-01-03 20:00:33 -08:00

85 lines
2.5 KiB
Python
Executable File

#!/usr/bin/python
"""
Simple example of sending output to multiple files and
monitoring them
"""
from mininet.topo import SingleSwitchTopo
from mininet.net import Mininet
from mininet.log import info, setLogLevel
from mininet.util import decode
from time import time
from select import poll, POLLIN
from subprocess import Popen, PIPE
def monitorFiles( outfiles, seconds, timeoutms ):
"Monitor set of files and return [(host, line)...]"
devnull = open( '/dev/null', 'w' )
tails, fdToFile, fdToHost = {}, {}, {}
for h, outfile in outfiles.items():
tail = Popen( [ 'tail', '-f', outfile ],
stdout=PIPE, stderr=devnull )
fd = tail.stdout.fileno()
tails[ h ] = tail
fdToFile[ fd ] = tail.stdout
fdToHost[ fd ] = h
# Prepare to poll output files
readable = poll()
for t in tails.values():
readable.register( t.stdout.fileno(), POLLIN )
# Run until a set number of seconds have elapsed
endTime = time() + seconds
while time() < endTime:
fdlist = readable.poll(timeoutms)
if fdlist:
for fd, _flags in fdlist:
f = fdToFile[ fd ]
host = fdToHost[ fd ]
# Wait for a line of output
line = f.readline().strip()
yield host, decode( line )
else:
# If we timed out, return nothing
yield None, ''
for t in tails.values():
t.terminate()
devnull.close() # Not really necessary
def monitorTest( N=3, seconds=3 ):
"Run pings and monitor multiple hosts"
topo = SingleSwitchTopo( N )
net = Mininet( topo, waitConnected=True )
net.start()
hosts = net.hosts
info( "Starting test...\n" )
server = hosts[ 0 ]
outfiles, errfiles = {}, {}
for h in hosts:
# Create and/or erase output files
outfiles[ h ] = '/tmp/%s.out' % h.name
errfiles[ h ] = '/tmp/%s.err' % h.name
h.cmd( 'echo >', outfiles[ h ] )
h.cmd( 'echo >', errfiles[ h ] )
# Start pings
h.cmdPrint('ping', server.IP(),
'>', outfiles[ h ],
'2>', errfiles[ h ],
'&' )
info( "Monitoring output for", seconds, "seconds\n" )
for h, line in monitorFiles( outfiles, seconds, timeoutms=500 ):
if h:
info( '%s: %s\n' % ( h.name, line ) )
for h in hosts:
h.cmd('kill %ping')
net.stop()
if __name__ == '__main__':
setLogLevel('info')
monitorTest()