我正在尝试编写一个可以用来监视我的python进程的SNMP代理。为此，我编写了一个使用pysnmp实现SNMP代理的类。
此代理的核心部分有效（即我可以使用snmpwalk来查询代理并且返回的数据是正确的）。为了允许我更新代理MIB值，我在其自己的线程中运行了dispatcher（）。我的问题是，当我使用snmpwalk与代理进行交谈时，我会得到超时（snmpwalk正确地走过MIB但是然后超时）。
有没有人能够洞察我做错了什么？
代理商代码如下：
import logging
from pysnmp import debug
from pysnmp.carrier.asyncore.dgram import udp
from pysnmp.entity import engine, config
from pysnmp.entity.rfc3413 import cmdrsp, context
from pysnmp.smi import exval
import threading
formatting = '[%(asctime)s-%(levelname)s]-(%(module)s) %(message)s'
logging.basicConfig(level=logging.DEBUG, format=formatting, )
class SNMPAgent(object):
def _main(self):
logging.debug("Creating SNMP Agent....")
self._snmpEngine = engine.SnmpEngine()
config.addTransport(
self._snmpEngine,
udp.domainName,
udp.UdpTransport().openServerMode((self._agentHost, self._agentPort))
)
config.addV1System(self._snmpEngine, 'my-area', self._communityName)
config.addVacmUser(self._snmpEngine,
2,
'my-area',
'noAuthNoPriv',
(1, 3, 6),
(1, 3, 6))
snmpContext = context.SnmpContext(self._snmpEngine)
mibBuilder = snmpContext.getMibInstrum().getMibBuilder()
mibBuilder.loadModules('HOST-RESOURCES-MIB')
self._mibInstrum = snmpContext.getMibInstrum()
self._hostRunTable, = mibBuilder.importSymbols('HOST-RESOURCES-MIB', 'hrSWRunEntry')
self._instanceId = self._hostRunTable.getInstIdFromIndices(1)
# The following shows the OID name mapping
#
# hrSWRunTable 1.3.6.1.2.1.25.4.2 <TABLE>
# hrSWRunEntry 1.3.6.1.2.1.25.4.2.1 <SEQUENCE>
# hrSWRunIndex 1.3.6.1.2.1.25.4.2.1.1 <Integer32>
# hrSWRunName 1.3.6.1.2.1.25.4.2.1.2 <InternationalDisplayString> 64 Char
# hrSWRunID 1.3.6.1.2.1.25.4.2.1.3 <ProductID>
# hrSWRunPath 1.3.6.1.2.1.25.4.2.1.4 <InternationalDisplayString> 128 octets
# hrSWRunParameters 1.3.6.1.2.1.25.4.2.1.5 <InternationalDisplayString> 128 octets
# hrSWRunType 1.3.6.1.2.1.25.4.2.1.6 <INTEGER>
# hrSWRunStatus 1.3.6.1.2.1.25.4.2.1.7 <INTEGER> <<===== This is the key variable used by Opennms
self._setVars()
cmdrsp.GetCommandResponder(self._snmpEngine, snmpContext)
cmdrsp.SetCommandResponder(self._snmpEngine, snmpContext)
cmdrsp.NextCommandResponder(self._snmpEngine, snmpContext)
cmdrsp.BulkCommandResponder(self._snmpEngine, snmpContext)
def runAgent(self):
'''
Run the Agent
'''
t = threading.Thread(target=self._runAgentFunc, args = ())
t.daemon = True
t.start()
def _runAgentFunc(self):
try:
self._snmpEngine.transportDispatcher.jobStarted(1)
self._snmpEngine.transportDispatcher.runDispatcher()
except:
self._snmpEngine.transportDispatcher.closeDispatcher()
raise
def updateAgentStatus(self, runStatus, text1, text2):
self._mibDict = {"hrSWRunIndex" : 1,
"hrSWRunName" : self._name,
"hrSWRunID" : self._enterpriseMIB,
"hrSWRunPath" : text1[:128] if text1 is not None else '',
"hrSWRunParameters" : text2[:128] if text1 is not None else '',
"hrSWRunType" : 4,
"hrSWRunStatus" : 1
}
self._setVars()
def _setVars(self):
varBinds = self._mibInstrum.writeVars((
(self._hostRunTable.name + (1,) + self._instanceId, self._mibDict["hrSWRunIndex"]),
(self._hostRunTable.name + (2,) + self._instanceId, self._mibDict["hrSWRunName"]), # <=== Must match OpenNMS service-name variable
(self._hostRunTable.name + (3,) + self._instanceId, self._mibDict["hrSWRunID" ]), #
(self._hostRunTable.name + (4,) + self._instanceId, self._mibDict["hrSWRunPath"]),
(self._hostRunTable.name + (5,) + self._instanceId, self._mibDict["hrSWRunParameters"]),
(self._hostRunTable.name + (6,) + self._instanceId, self._mibDict["hrSWRunType"]), # Values are ==> unknown(1), operatingSystem(2), deviceDriver(3), application(4)
(self._hostRunTable.name + (7,) + self._instanceId, self._mibDict["hrSWRunStatus"]) #<<=== This is the status number OpenNMS looks at Values are ==> running(1), runnable(2), notRunnable(3), invalid(4)
))
def __init__(self, name, host, port, community, text1='Service up', text2=''):
'''
#=======================================================================
# Constructor
# name -- the (process) name the agent should publish (must match
# the openNMS name
# host -- the host name or ip the agent will run on
# port -- the port the snmp agent will listen on
# community -- the community name the agent will use (usually 'public')
# text1 -- the first status text string published (128 char max)
# text2 -- the second status text string published (128 char max)
#=======================================================================
'''
self._name = name
self._agentHost = host
self._agentPort = port
self._communityName = community
self._enterpriseMIB = (1, 3, 6, 1, 4, 1, 50000, 0) # Made up for now
self._mibInstrum = None
self._snmpEngine = None
self._dataChanged = False
self._mibDict = {"hrSWRunIndex" : 1,
"hrSWRunName" : self._name,
"hrSWRunID" : self._enterpriseMIB,
"hrSWRunPath" : text1[:128] if text1 is not None else '',
"hrSWRunParameters" : text2[:128] if text1 is not None else '',
"hrSWRunType" : 4,
"hrSWRunStatus" : 1
}
self._main()
我按如下方式调用此代码（这只是测试我可以更改状态）：
from SNMPAgent import SNMPAgent
from time import sleep
agent = SNMPAgent("test", "127.0.0.1", 12345, "public", "This is my test message 1", "This is my test message 2")
agent.runAgent()
sleep(10) # Wait for it to start
while True:
agent.updateAgentStatus(3, "Oh no", "Something is wrong!")
sleep(30)
agent.updateAgentStatus(2, "Whew", "Everything is fixed")
sleep(30)
要使用代理MIB：
snmpwalk -v 2c -c public -n my-context 127.0.0.1:12345 1.3.6.1.2.1.25.4.2
这显示了数据更新，但在步行结束时MIB代理超时：
HOST-RESOURCES-MIB::hrSWRunIndex.1 = INTEGER: 1
HOST-RESOURCES-MIB::hrSWRunName.1 = STRING: "test"
HOST-RESOURCES-MIB::hrSWRunID.1 = OID: SNMPv2-SMI::enterprises.50000.0
HOST-RESOURCES-MIB::hrSWRunPath.1 = STRING: "Whew"
HOST-RESOURCES-MIB::hrSWRunParameters.1 = STRING: "Everything is fixed"
HOST-RESOURCES-MIB::hrSWRunType.1 = INTEGER: application(4)
HOST-RESOURCES-MIB::hrSWRunStatus.1 = INTEGER: running(1)
Timeout: No Response from 127.0.0.1:12345
答案 0 :(得分：1)
启用pysnmp调试会显示由特定OID的未设置整数值引起的序列化错误：
[2017-01-13 02:05:18,387-DEBUG]-(debug) generateResponseMsg: Message:
version='version-2c'
community=public
data=PDUs:
response=ResponsePDU:
request-id=1950819527
error-status='noError'
error-index=0
variable-bindings=VarBindList:
VarBind:
name=1.3.6.1.2.1.25.5.1.1.1.1
=_BindValue:
value=ObjectSyntax:
simple=SimpleSyntax:
integer-value=<no value>
2017-01-13 02:05:18,387 pysnmp: generateResponseMsg: serialization failure: Uninitialized ASN.1 value ("__eq__" attribute looked up)
[2017-01-13 02:05:18,387-DEBUG]-(debug) generateResponseMsg: serialization failure: Uninitialized ASN.1 value ("__eq__" attribute looked up)
2017-01-13 02:05:18,388 pysnmp: StatusInformation: {'errorIndication': <pysnmp.proto.errind.SerializationError object at 0x10162f828>}
[2017-01-13 02:05:18,388-DEBUG]-(debug) StatusInformation: {'errorIndication': <pysnmp.proto.errind.SerializationError object at 0x10162f828>}
您应该确保为所有非默认的SNMP表列设置值。
作为旁注，您似乎在没有显式同步的情况下从主代理线程和SNMP代理线程管理您的MIB。这可能会导致竞争条件......