lantz
f0c726a42f
This helps with virtualenv although it can open up another security hole if you end up using an unexpected python interpreter. Overall it seems to make sense to err on the side of usability but it's good to be aware of security. However, for the remaining utility scripts that require python 2, we explicitly note this with #!/usr/bin/python2.
85 lines
2.5 KiB
Python
Executable File
85 lines
2.5 KiB
Python
Executable File
#!/usr/bin/env python
|
|
|
|
"""
|
|
Simple example of sending output to multiple files and
|
|
monitoring them
|
|
"""
|
|
|
|
|
|
from time import time
|
|
from select import poll, POLLIN
|
|
from subprocess import Popen, PIPE
|
|
|
|
from mininet.topo import SingleSwitchTopo
|
|
from mininet.net import Mininet
|
|
from mininet.log import info, setLogLevel
|
|
from mininet.util import decode
|
|
|
|
|
|
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()
|