Fetching variables¶
Fetch scalar MIB variables (SNMPv1)¶
Perform SNMP GET operation with the following options:
- with SNMPv1, community ‘public’
- over IPv4/UDP
- to an Agent at demo.snmplabs.com:161
- for OIDs in tuple form
This script performs similar to the following Net-SNMP command:
$ snmpget -v1 -c public -ObentU demo.snmplabs.com 1.3.6.1.2.1.1.1.0 1.3.6.1.2.1.1.3.0
from pysnmp.carrier.asyncore.dispatch import AsyncoreDispatcher
from pysnmp.carrier.asyncore.dgram import udp, udp6
from pyasn1.codec.ber import encoder, decoder
from pysnmp.proto import api
from time import time
# Protocol version to use
pMod = api.PROTOCOL_MODULES[api.SNMP_VERSION_1]
# pMod = api.protoModules[api.protoVersion2c]
# Build PDU
reqPDU = pMod.GetRequestPDU()
pMod.apiPDU.setDefaults(reqPDU)
pMod.apiPDU.setVarBinds(
reqPDU, (('1.3.6.1.2.1.1.1.0', pMod.Null('')),
('1.3.6.1.2.1.1.3.0', pMod.Null('')))
)
# Build message
reqMsg = pMod.Message()
pMod.apiMessage.setDefaults(reqMsg)
pMod.apiMessage.setCommunity(reqMsg, 'public')
pMod.apiMessage.setPDU(reqMsg, reqPDU)
startedAt = time()
def cbTimerFun(timeNow):
if timeNow - startedAt > 3:
raise Exception("Request timed out")
# noinspection PyUnusedLocal,PyUnusedLocal
def cbRecvFun(transportDispatcher, transportDomain, transportAddress,
wholeMsg, reqPDU=reqPDU):
while wholeMsg:
rspMsg, wholeMsg = decoder.decode(wholeMsg, asn1Spec=pMod.Message())
rspPDU = pMod.apiMessage.getPDU(rspMsg)
# Match response to request
if pMod.apiPDU.getRequestID(reqPDU) == pMod.apiPDU.getRequestID(rspPDU):
# Check for SNMP errors reported
errorStatus = pMod.apiPDU.getErrorStatus(rspPDU)
if errorStatus:
print(errorStatus.prettyPrint())
else:
for oid, val in pMod.apiPDU.getVarBinds(rspPDU):
print('%s = %s' % (oid.prettyPrint(), val.prettyPrint()))
transportDispatcher.jobFinished(1)
return wholeMsg
transportDispatcher = AsyncoreDispatcher()
transportDispatcher.registerRecvCbFun(cbRecvFun)
transportDispatcher.registerTimerCbFun(cbTimerFun)
# UDP/IPv4
transportDispatcher.registerTransport(
udp.DOMAIN_NAME, udp.UdpSocketTransport().openClientMode()
)
# Pass message to dispatcher
transportDispatcher.sendMessage(
encoder.encode(reqMsg), udp.DOMAIN_NAME, ('demo.snmplabs.com', 161)
)
transportDispatcher.jobStarted(1)
## UDP/IPv6 (second copy of the same PDU will be sent)
# transportDispatcher.registerTransport(
# udp6.domainName, udp6.Udp6SocketTransport().openClientMode()
# )
# Pass message to dispatcher
# transportDispatcher.sendMessage(
# encoder.encode(reqMsg), udp6.domainName, ('::1', 161)
# )
# transportDispatcher.jobStarted(1)
# Dispatcher will finish as job#1 counter reaches zero
transportDispatcher.runDispatcher()
transportDispatcher.closeDispatcher()
Download
script.
See also: library reference.