Agent-side MIB implementations
******************************


Implementing scalar MIB objects
===============================

Listen and respond to SNMP GET/SET/GETNEXT/GETBULK queries with the
following options:

* SNMPv2c

* with SNMP community "public"

* serving custom Managed Object Instance defined within this script

* allow read access only to the subtree where the custom MIB object
  resides

* over IPv4/UDP, listening at 127.0.0.1:161

* using Twisted fraework for network transport

Either of the following Net-SNMP commands will walk this Agent:

   $ snmpwalk -v2c -c public 127.0.0.1 .1.3.6

   import sys
   from twisted.internet import reactor
   from pysnmp.entity import engine, config
   from pysnmp.entity.rfc3413 import cmdrsp, context
   from pysnmp.proto import rfc1902
   from pysnmp.carrier.twisted.dgram import udp

   # Create SNMP engine with autogenernated engineID and pre-bound
   # to socket transport dispatcher
   snmpEngine = engine.SnmpEngine()

   # Transport setup

   # UDP over IPv4
   config.addTransport(
       snmpEngine,
       udp.domainName,
       udp.UdpTwistedTransport().openServerMode(('127.0.0.1', 161))
   )

   # SNMPv2c setup

   # SecurityName <-> CommunityName mapping.
   config.addV1System(snmpEngine, 'my-area', 'public')

   # Allow read MIB access for this user / securityModels at VACM
   config.addVacmUser(snmpEngine, 2, 'my-area', 'noAuthNoPriv', (1, 3, 6, 5))

   # Create an SNMP context
   snmpContext = context.SnmpContext(snmpEngine)

   # --- create custom Managed Object Instance ---

   mibBuilder = snmpContext.getMibInstrum().getMibBuilder()

   MibScalar, MibScalarInstance = mibBuilder.importSymbols(
       'SNMPv2-SMI', 'MibScalar', 'MibScalarInstance'
   )


   class MyStaticMibScalarInstance(MibScalarInstance):
       # noinspection PyUnusedLocal,PyUnusedLocal
       def getValue(self, name, idx):
           return self.getSyntax().clone(
               'Python %s running on a %s platform' % (sys.version, sys.platform)
           )


   mibBuilder.exportSymbols(
       '__MY_MIB', MibScalar((1, 3, 6, 5, 1), rfc1902.OctetString()),
       MyStaticMibScalarInstance((1, 3, 6, 5, 1), (0,), rfc1902.OctetString())
   )

   # --- end of Managed Object Instance initialization ----

   # Register SNMP Applications at the SNMP engine for particular SNMP context
   cmdrsp.GetCommandResponder(snmpEngine, snmpContext)
   cmdrsp.NextCommandResponder(snmpEngine, snmpContext)
   cmdrsp.BulkCommandResponder(snmpEngine, snmpContext)

   # Run Twisted main loop
   reactor.run()

"Download" script.

See also: library reference.
