Asynchronous: asyncoreΒΆ

With asyncore API your scripts get CPU time on socket events being watched for by select dispatcher. Your code live mostly in isolated functions (or any callable objects).

In most examples approximate analogues of well known Net-SNMP snmp* tools command line options are shown. That may help those readers who, by chance are familiar with Net-SNMP tools, better understanding what example code doe

Here’s a quick example on a simple SNMP GET by high-level API:

  • with SNMPv1, community ‘public’
  • over IPv4/UDP
  • to an Agent at demo.snmplabs.com:161
  • for two instances of SNMPv2-MIB::sysDescr.0 MIB object,
from pysnmp.hlapi.asyncore import *


# noinspection PyUnusedLocal,PyUnusedLocal,PyUnusedLocal
def cbFun(snmpEngine, sendRequestHandle, errorIndication,
          errorStatus, errorIndex, varBinds, cbCtx):
    if errorIndication:
        print(errorIndication)
        return
    elif errorStatus:
        print('%s at %s' % (errorStatus.prettyPrint(),
                            errorIndex and varBindTable[-1][int(errorIndex) - 1][0] or '?'))
        return
    else:
        for varBind in varBinds:
            print(' = '.join([x.prettyPrint() for x in varBind]))


snmpEngine = SnmpEngine()

getCmd(snmpEngine,
       CommunityData('public'),
       UdpTransportTarget(('demo.snmplabs.com', 161)),
       ContextData(),
       ObjectType(ObjectIdentity('SNMPv2-MIB', 'sysDescr', 0)),
       cbFun=cbFun)

snmpEngine.transportDispatcher.runDispatcher()

To make use of SNMPv3 and USM, the following code performs a series of SNMP GETNEXT operations effectively fetching a table of SNMP variables from SNMP Agent:

  • with SNMPv3, user ‘usr-md5-none’, MD5 authentication, no privacy
  • over IPv4/UDP
  • to an Agent at demo.snmplabs.com:161
  • for all OIDs in IF-MIB
from pysnmp.hlapi.asyncore import *


# noinspection PyUnusedLocal,PyUnusedLocal,PyUnusedLocal
def cbFun(snmpEngine, sendRequestHandle, errorIndication,
          errorStatus, errorIndex, varBindTable, cbCtx):
    if errorIndication:
        print(errorIndication)
        return
    elif errorStatus:
        print('%s at %s' % (errorStatus.prettyPrint(),
                            errorIndex and varBindTable[-1][int(errorIndex) - 1][0] or '?'))
        return
    else:
        for varBindRow in varBindTable:
            for varBind in varBindRow:
                print(' = '.join([x.prettyPrint() for x in varBind]))

    return True  # request lower layers to do GETNEXT and call us back


snmpEngine = SnmpEngine()

nextCmd(snmpEngine,
        UsmUserData('usr-md5-none', 'authkey1'),
        UdpTransportTarget(('demo.snmplabs.com', 161)),
        ContextData(),
        ObjectType(ObjectIdentity('SNMPv2-MIB', 'system')),
        ObjectType(ObjectIdentity('IF-MIB', 'ifTable')),
        cbFun=cbFun)

snmpEngine.transportDispatcher.runDispatcher()

More examples on Command Generator API usage follow.

Sending SNMP TRAP’s and INFORM’s is as easy with PySNMP library. The following code sends SNMP TRAP:

  • SNMPv1
  • with community name ‘public’
  • over IPv4/UDP
  • send TRAP notification
  • with Generic Trap #1 (warmStart) and Specific Trap 0
  • with default Uptime
  • with default Agent Address
  • with Enterprise OID 1.3.6.1.4.1.20408.4.1.1.2
  • include managed object information ‘1.3.6.1.2.1.1.1.0’ = ‘my system’
from pysnmp.hlapi.asyncore import *

snmpEngine = SnmpEngine()

sendNotification(
    snmpEngine,
    CommunityData('public', mpModel=0),
    UdpTransportTarget(('demo.snmplabs.com', 162)),
    ContextData(),
    'trap',
    NotificationType(
        ObjectIdentity('1.3.6.1.6.3.1.1.5.2')
    ).addVarBinds(
        ('1.3.6.1.6.3.1.1.4.3.0', '1.3.6.1.4.1.20408.4.1.1.2'),
        ('1.3.6.1.2.1.1.1.0', OctetString('my system'))
    )
)

snmpEngine.transportDispatcher.runDispatcher()

More examples on Notification Originator API usage follow.

More sophisticated or less popular SNMP operations can still be performed with PySNMP through its Native API to Standard SNMP Applications.