"""
Fetch whole SNMP table
++++++++++++++++++++++

Send a series of SNMP GETNEXT requests using the following options:

* with SNMPv1, community 'public'
* over IPv4/UDP
* to an Agent at demo.snmplabs.com:161
* for some columns of the IF-MIB::ifEntry table
* stop when response OIDs leave the scopes of initial OIDs

Functionally similar to:

| $ snmpwalk -v1 -c public demo.snmplabs.com \
|        IF-MIB::ifDescr \
|        IF-MIB::ifType \
|        IF-MIB::ifMtu \
|        IF-MIB::ifSpeed \
|        IF-MIB::ifPhysAddress \
|        IF-MIB::ifType \

"""#
from pysnmp.entity.rfc3413.oneliner.cmdgen import *

for errorIndication, \
    errorStatus, \
    errorIndex, \
    varBinds in nextCmd(SnmpEngine(),
                        CommunityData('public', mpModel=0),
                        UdpTransportTarget(('demo.snmplabs.com', 161)),
                        ContextData(),
                        ObjectType(ObjectIdentity('IF-MIB', 'ifDescr')),
                        ObjectType(ObjectIdentity('IF-MIB', 'ifType')),
                        ObjectType(ObjectIdentity('IF-MIB', 'ifMtu')),
                        ObjectType(ObjectIdentity('IF-MIB', 'ifSpeed')),
                        ObjectType(ObjectIdentity('IF-MIB', 'ifPhysAddress')),
                        ObjectType(ObjectIdentity('IF-MIB', 'ifType')),
                        lexicographicMode=False):

    if errorIndication:
        print(errorIndication)
        break
    elif errorStatus:
        print('%s at %s' % (
                errorStatus.prettyPrint(),
                errorIndex and varBinds[int(errorIndex)-1][0] or '?'
            )
        )
        break
    else:
        for varBind in varBinds:
            print(' = '.join([ x.prettyPrint() for x in varBind ]))