PySNMP: load error: Bad OctetString initializer

I have the following example from the pysnmp page: # GET Command Generator from pysnmp.entity.rfc3413.oneliner import cmdgen

errorIndication, errorStatus, \
                 errorIndex, varBinds = cmdgen.CommandGenerator().getCmd(
    # SNMP v1
#    cmdgen.CommunityData('test-agent', 'public', 0),
    # SNMP v2
    cmdgen.CommunityData('test-agent', 'public'),
    # SNMP v3
#    cmdgen.UsmUserData('test-user', 'authkey1', 'privkey1'),
    cmdgen.UdpTransportTarget(('localhost', 161)),
    # Plain OID
    (1,3,6,1,2,1,1,1,0),
    # ((mib-name, mib-symbol), instance-id)
    (('SNMPv2-MIB', 'sysDescr'), 0)
    )

if errorIndication:
    print errorIndication
else:
    if errorStatus:
        print '%s at %s\n' % (
            errorStatus.prettyPrint(),
            errorIndex and varBinds[int(errorIndex)-1] or '?'
            )
    else:
        for name, val in varBinds:
            print '%s = %s' % (name.prettyPrint(), val.prettyPrint())

I made sure that SNMP is running on my machine. I checked in the console with the following command:

snmpget -v2c -Cf -c public localhost 1.3.6.1.2.1.1.1.0

Which worked fine. If i execute the python code above I get the following error:

SmiError: MIB module "pysnmp/smi/mibs/SNMP-COMMUNITY-MIB.py" load error: MIB module "pysnmp/smi/mibs/SNMP-FRAMEWORK-MIB.py" load error: Bad OctetString initializer '[128, 0, 79, 184, 5, 192, 168, 1, 50, 371, 210, 26, 162, 157]'

The numbers at the end change with each execution (seems to a timestamp or somehting like that). I'm using python 2.7 and the most recent version of pySNMP (4.2.1). Does anyone know what's the problem with this example code?

Solution

That is a bug in pysnmp 4.2.1 which has been fixed to the latest pysnmp release candidates (it looks like this bug more frequently occurs on Macs for some reason).

Here's a link to currently most recent rc:

http://sourceforge.net/projects/pysnmp/files/pysnmp/4.2.2/pysnmp-4.2.2rc5.tar.gz/download

-ilya