Transport tweaks

Custom request timeout

Send SNMP GET request using the following options:

• with SNMPv2c, community ‘public’
• over IPv4/UDP
• to an Agent at demo.snmplabs.com:161
• for an OID in string form
• use custom timeout and request retries values

Transport timing settings (maximum number of request retries and individual request timeout in seconds) can be set on a per-target basis as explained by the code that follows.

Keep in mind that while timeout value can be specified in fractions of a second, default pysnmp timer resolution is quite low (about 0.5 sec) so there’s no much point in using timeouts which is not a multiple of 0.5 Internal timer can be programmatically adjusted to finer resolution if needed.

If retries value is set to 0, pysnmp will issue a single request. Even if no response arrives, there will be no retry. Likewise, retries=1 means one initial request plus one retry.

Functionally similar to:

$ snmpget -v1 -c public -t 2 -r 0 demo.snmplabs.com 1.3.6.1.2.1.1.1.0

from pysnmp.hlapi.v1arch import *

iterator = getCmd(
    SnmpDispatcher(),
    CommunityData('public'),
    UdpTransportTarget(
       ('demo.snmplabs.com', 161), timeout=2.0, retries=0
    ),
    ('1.3.6.1.2.1.1.1.0', None)
)

errorIndication, errorStatus, errorIndex, varBinds = next(iterator)

if errorIndication:
    print(errorIndication)

elif errorStatus:
    print('%s at %s' % (errorStatus.prettyPrint(),
                        errorIndex and varBinds[int(errorIndex) - 1][0] or '?'))

else:
    for varBind in varBinds:
        print(' = '.join([x.prettyPrint() for x in varBind]))

Download script.

GET over IPv6

Send SNMP GET request using the following options:

• with SNMPv2c, community ‘public’
• over IPv6/UDP
• to an Agent at [::1]:161
• for three OIDs in string form

Functionally similar to:

$ snmpget -v2c -c public udp6:[::1]:161 1.3.6.1.2.1.1.1.0 1.3.6.1.2.1.1.2.0 1.3.6.1.2.1.1.3.0

from pysnmp.hlapi.v1arch import *

iterator = getCmd(
    SnmpDispatcher(),
    CommunityData('public'),
    Udp6TransportTarget(('::1', 161)),
    ('1.3.6.1.2.1.1.1.0', None),
    ('1.3.6.1.2.1.1.2.0', None),
    ('1.3.6.1.2.1.1.3.0', None)
)

errorIndication, errorStatus, errorIndex, varBinds = next(iterator)

if errorIndication:
    print(errorIndication)

elif errorStatus:
    print('%s at %s' % (errorStatus.prettyPrint(),
                        errorIndex and varBinds[int(errorIndex) - 1][0] or '?'))

else:
    for varBind in varBinds:
        print(' = '.join([x.prettyPrint() for x in varBind]))

Download script.

See also: library reference.