So far in my experience with Python, it's error messages have been clear,
concise, and quite good at fingering my errors. However, the message below has
me stumped. The routine in question has been running for weeks with no
problems, then yesterday I got the following:
Traceback (most recent call last):
File "./Connection_Monitor.py", line 146, in <module>
Google_up, Google_summary, Google_RTT, Google_stddev =
Google.connection_test()
File
"/Users/wrw/Dev/Python/Connection_Monitor/Version2.2/WorkingCopy/network.py",
line 101, in connection_test
#
IndexError: list index out of range
The routine is pasted in below:
def connection_test(self):
self.network_up = True
self.error = None
ping_result = subprocess.Popen(['ping', '-qc6', self.target_IP], stderr
= subprocess.PIPE, stdout = subprocess.PIPE).communicate()[0]
found_0 = '0 packets received' in ping_result
found_1 = '1 packets received' in ping_result
if found_0 == True or found_1 == True:
self.network_up = False
self.ping_summary = 'No route to host'
self.ping_RTT = 'NA'
self.ping_stddev = 'NA'
return self.network_up, self.ping_summary, self.ping_RTT,
self.ping_stddev
#
That particular command line generates 6 ping packets in quiet mode (summary
only) and the amount of text returned, even when the ping fails is minimal.
My puzzle two-fold. First: how could that code generate an "index our of
range" error, and second: line 101 (the one fingered by the error message) is
the line following the return statement, the one that contains the # character.
I've seen that sort of line slippage when I forgot a ":", but that doesn't
seem to be the case here.
Python 2.7.3 from Python.org, running on Mac OS-X 10.8.2.
For what it is worth, the definitions of the rest of the class variables follow
(pretty simple minded):
def __init__(self, target_name):
lan_status = ''
wan_status = ''
path_status = ''
ping_summary = ''
ping_RTT = ''
ping_stddev = ''
target_error = ''
network_up = True
target_error, initial_route, hop_count, target_IP =
find_initial_route(target_name)
self.target_error = target_error
self.initial_route = initial_route
self.hop_count = hop_count
self.gateway = initial_route[0]
self.target_name = target_name
self.target_IP = target_IP
self.hop_count = hop_count
self.lan_status = lan_status
self.wan_status = wan_status
self.path_status = path_status
self.network_up = network_up
self.ping_summary = ping_summary
self.ping_RTT = ping_RTT
self.ping_stddev = ping_stddev
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