Agent side¶
Implementing MIB objects¶
This script explains how SNMP Agent application could model real-world data as Managed Objects defined in MIB.
from pysnmp.smi import builder
# MIB Builder is normally pre-created by SNMP engine
mibBuilder = builder.MibBuilder()
#
# This may be done in a stand-alone file and then loaded up
# by SNMP Agent
#
# A base class for a custom Managed Object
MibScalarInstance, = mibBuilder.importSymbols(
'SNMPv2-SMI', 'MibScalarInstance'
)
# Managed object specification
sysLocation, = mibBuilder.importSymbols('SNMPv2-MIB', 'sysLocation')
# Custom Managed Object
class MySysLocationInstance(MibScalarInstance):
# noinspection PyUnusedLocal
def readGet(self, name, *args):
# Just return a custom value
return name, self.syntax.clone('The Leaky Cauldron')
sysLocationInstance = MySysLocationInstance(
sysLocation.name, (0,), sysLocation.syntax
)
# Register Managed Object with a MIB tree
mibBuilder.exportSymbols(
# '__' prefixed MIB modules take precedence on indexing
'__MY-LOCATION-MIB', sysLocationInstance=sysLocationInstance
)
if __name__ == '__main__':
#
# This is what is done internally by Agent.
#
from pysnmp.smi import instrum, exval
mibInstrum = instrum.MibInstrumController(mibBuilder)
print('Remote manager read access to MIB instrumentation (table walk)')
oid, val = (), None
while 1:
oid, val = mibInstrum.readNextVars(((oid, val),))[0]
if exval.endOfMib.isSameTypeWith(val):
break
print(oid, val.prettyPrint())
Download
script.
Agent operations on MIB¶
This script explains how SNMP Agent application manipulates its MIB possibly triggered by SNMP Manager’s commands.
# SNMP agent backend e.g. Agent access to Managed Objects
from pysnmp.smi import builder, instrum, exval
print('Loading MIB modules...'),
mibBuilder = builder.MibBuilder().loadModules(
'SNMPv2-MIB', 'SNMP-FRAMEWORK-MIB', 'SNMP-COMMUNITY-MIB'
)
print('done')
print('Building MIB tree...'),
mibInstrum = instrum.MibInstrumController(mibBuilder)
print('done')
print('Building table entry index from human-friendly representation...'),
snmpCommunityEntry, = mibBuilder.importSymbols(
'SNMP-COMMUNITY-MIB', 'snmpCommunityEntry'
)
instanceId = snmpCommunityEntry.getInstIdFromIndices('my-router')
print('done')
print('Create/update SNMP-COMMUNITY-MIB::snmpCommunityEntry table row: ')
varBinds = mibInstrum.writeVars(
((snmpCommunityEntry.name + (2,) + instanceId, 'mycomm'),
(snmpCommunityEntry.name + (3,) + instanceId, 'mynmsname'),
(snmpCommunityEntry.name + (7,) + instanceId, 'volatile'))
)
for oid, val in varBinds:
print('%s = %s' % ('.'.join([str(x) for x in oid]), not val.isValue and 'N/A' or val.prettyPrint()))
print('done')
print('Read whole MIB (table walk)')
oid, val = (), None
while True:
oid, val = mibInstrum.readNextVars(((oid, val),))[0]
if exval.endOfMib.isSameTypeWith(val):
break
print('%s = %s' % ('.'.join([str(x) for x in oid]), not val.isValue and 'N/A' or val.prettyPrint()))
print('done')
print('Unloading MIB modules...'),
mibBuilder.unloadModules()
print('done')
Download
script.
See also: library reference.