Re: [pysnmp-users] pysnmp / pyasn1 decode problem with multi-line traps
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Re: [pysnmp-users] pysnmp / pyasn1 decode problem with multi-line traps
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From: Tom <to...@we...> - 2015-03-11 06:02:56
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Hi -ilya,
thanks for the quick answer.
Your solution sounds great but unfortunately I have some troubles with the implementation.
I changed the script as follows:
...
print('Var-binds:')
result = {}
for oid, val in varBinds:
print('%s = %s' % (oid.prettyPrint(), val.prettyPrint()))
result[oid] = val.asOctets()
print('%s = %s' % (oid.prettyPrint(), result.prettyPrint()))
...
When I run the script and send some test data via snmp to the server I got this error message.
Traceback (most recent call last):
File "snmp-transports.py", line 115, in <module>
transportDispatcher.runDispatcher()
File "/usr/lib/python2.7/dist-packages/pysnmp/carrier/asynsock/dispatch.py", line 41, in runDispatcher
raise PySnmpError('poll error: %s' % ';'.join(format_exception(*exc_info())))
pysnmp.error.PySnmpError: poll error: Traceback (most recent call last):
; File "/usr/lib/python2.7/dist-packages/pysnmp/carrier/asynsock/dispatch.py", line 37, in runDispatcher
use_poll=True, map=self.__sockMap, count=1)
; File "/usr/lib/python2.7/asyncore.py", line 220, in loop
poll_fun(timeout, map)
; File "/usr/lib/python2.7/asyncore.py", line 201, in poll2
readwrite(obj, flags)
; File "/usr/lib/python2.7/asyncore.py", line 123, in readwrite
obj.handle_error()
; File "/usr/lib/python2.7/asyncore.py", line 108, in readwrite
obj.handle_read_event()
; File "/usr/lib/python2.7/asyncore.py", line 449, in handle_read_event
self.handle_read()
; File "/usr/lib/python2.7/dist-packages/pysnmp/carrier/asynsock/dgram/base.py", line 83, in handle_read
self._cbFun(self, transportAddress, incomingMessage)
; File "/usr/lib/python2.7/dist-packages/pysnmp/carrier/base.py", line 52, in _cbFun
self, transportDomain, transportAddress, incomingMessage
; File "snmp-transports.py", line 59, in trapCallback
result[oid] = val.asOctets()
;AttributeError: ObjectSyntax instance has no attribute 'asOctets'
Where is my mistake?
Does it only works if a hex value is send by snmp?
How can I check if the value is hex or not?
Sorry for the stupid questions but I'm really new to python and their modules.
Kind regards,
Tom
> Am 10.03.2015 um 07:03 schrieb Ilya Etingof <il...@gl...>:
>
> Hi Tom,
>
> The OctetString type prints its contents in hex form if there’s a potentially non-printable characters there that may be lost when printing to the terminal. Use .asOctets() method to retrieve data in pure octet-string form:
>
> >>> s = OctetString(hexValue='4f70657261746f722058585858585858585858203a20585858585858585858582c2058585858585858202c204c6f63616c6c792061757468656e74696361746564202d207375636365737366756c6c79207369676e6564206f6e20746f20746865207465726d696e616c20275858582e5858582e582e584058272061742031343a3238207573696e672027585858585858585820585858205858585858585858272e0a4f70657261746f722050726f66696c65733a2058585858585858585858585858')
> >>> s.prettyPrint()
> '0x4f70657261746f722058585858585858585858203a20585858585858585858582c2058585858585858202c204c6f63616c6c792061757468656e74696361746564202d207375636365737366756c6c79207369676e6564206f6e20746f20746865207465726d696e616c20275858582e5858582e582e584058272061742031343a3238207573696e672027585858585858585820585858205858585858585858272e0a4f70657261746f722050726f66696c65733a2058585858585858585858585858'
> >>> s.asOctets()
> "Operator XXXXXXXXXX : XXXXXXXXXX, XXXXXXX , Locally authenticated - successfully signed on to the terminal 'XXX.XXX.X.X@X' at 14:28 using 'XXXXXXXX XXX XXXXXXXX'.\nOperator Profiles: XXXXXXXXXXXXX"
>
> -ilya
>
>> On 09 Mar 2015, at 22:23, Tom Kr. <to...@we...> wrote:
>>
>>
>> Hi there,
>>
>> I'm new to this mailing list and I have a issue with the pysnmp / pyasn1 module.
>> I use python with version 3.4 and pysnmp with version 4.2.5.
>> The OS is Ubuntu server 14.04.2.
>>
>> # lsb_release -a
>> No LSB modules are available.
>> Distributor ID: Ubuntu
>> Description: Ubuntu 14.04.2 LTS
>> Release: 14.04
>> Codename: trusty
>>
>> ii python-pysnmp4 4.2.5-1 all Python SNMP library for agents and managers (Python 2 module)
>> ii python-pyasn1 0.1.7-1ubuntu2 all ASN.1 library for Python (Python 2 module)
>> ii python3.4 3.4.0-2ubuntu1 amd64 Interactive high-level object-oriented language (version 3.4)
>>
>> I try to use the following script to read snmp traps and print this traps on the screen.
>> But unfortunately I have some troubles with multi-line traps.
>> This traps are only shown as hex values.
>> I think the problem is the decoder but I'm not very familiar with python and also not with pysnmp.
>>
>> I hope someone of you can help me or give me some ideas what I should do next.
>> For the moment I have no idea.
>>
>> The script:
>> ----------------------------------------------------------------------------------------------
>> import sys,os
>>
>> sys.path.append('/usr/share/pyshared/')
>>
>> from pysnmp.carrier.asynsock.dispatch import AsynsockDispatcher
>> from pysnmp.carrier.asynsock.dgram import udp, udp6
>> from pyasn1.codec.ber import decoder
>> from pysnmp.proto import api
>>
>> def trapCallback(transportDispatcher, transportDomain, transportAddress, wholeMsg):
>> while wholeMsg:
>> msgVer = int(api.decodeMessageVersion(wholeMsg))
>> if msgVer in api.protoModules:
>> pMod = api.protoModules[msgVer]
>> else:
>> print('Unsupported SNMP version %s' % msgVer)
>> return
>> reqMsg, wholeMsg = decoder.decode(
>> wholeMsg, asn1Spec=pMod.Message(),
>> )
>> print('Notification message from %s:%s: ' % (
>> transportDomain, transportAddress
>> )
>> )
>> reqPDU = pMod.apiMessage.getPDU(reqMsg)
>> if reqPDU.isSameTypeWith(pMod.TrapPDU()):
>> if msgVer == api.protoVersion1:
>> print('Enterprise: %s' % (
>> pMod.apiTrapPDU.getEnterprise(reqPDU).prettyPrint()
>> )
>> )
>> print('Agent Address: %s' % (
>> pMod.apiTrapPDU.getAgentAddr(reqPDU).prettyPrint()
>> )
>> )
>> print('Generic Trap: %s' % (
>> pMod.apiTrapPDU.getGenericTrap(reqPDU).prettyPrint()
>> )
>> )
>> print('Specific Trap: %s' % (
>> pMod.apiTrapPDU.getSpecificTrap(reqPDU).prettyPrint()
>> )
>> )
>> print('Uptime: %s' % (
>> pMod.apiTrapPDU.getTimeStamp(reqPDU).prettyPrint()
>> )
>> )
>> varBinds = pMod.apiTrapPDU.getVarBindList(reqPDU)
>> else:
>> varBinds = pMod.apiPDU.getVarBindList(reqPDU)
>> print('Var-binds:')
>> for oid, val in varBinds:
>> print('%s = %s' % (oid.prettyPrint(), val.prettyPrint()))
>> return wholeMsg
>>
>> transportDispatcher = AsynsockDispatcher()
>>
>> transportDispatcher.registerRecvCbFun(trapCallback)
>>
>> # UDP/IPv4
>> transportDispatcher.registerTransport(
>> udp.domainName, udp.UdpSocketTransport().openServerMode(('localhost', 162))
>> )
>>
>> # UDP/IPv6
>> transportDispatcher.registerTransport(
>> udp6.domainName, udp6.Udp6SocketTransport().openServerMode(('::1', 162))
>> )
>>
>> transportDispatcher.jobStarted(1)
>>
>> try:
>> # Dispatcher will never finish as job#1 never reaches zero
>> transportDispatcher.runDispatcher()
>> except:
>> transportDispatcher.closeDispatcher()
>> raise
>> ----------------------------------------------------------------------------------------------
>>
>>
>> As you can see, the script is an example from the project side.
>> (http://pysnmp.sourceforge.net/examples/current/v1arch/manager/ntfrcv/v2c-multiple-transports.html)
>>
>> This is the part of the trap where the hex value is shown instead of the plain text.
>> string=0x4f70657261746f722058585858585858585858203a20585858585858585858582c2058585858585858202c204c6f63616c6c792061757468656e74696361746564202d207375636365737366756c6c79207369676e6564206f6e20746f20746865207465726d696e616c20275858582e5858582e582e584058272061742031343a3238207573696e672027585858585858585820585858205858585858585858272e0a4f70657261746f722050726f66696c65733a2058585858585858585858585858
>>
>> This is the message I would expect.
>> "Operator XXXXXXXXXX : XXXXXXXXXX, XXXXXXX , Locally authenticated - successfully signed on to the terminal 'XXX.XXX.X.X@X' at 14:28using 'XXXXXXXX XXX XXXXXXXX'.
>> Operator Profiles: XXXXXXXXXXXXX"
>>
>> For me, the problem is located at the line feed. Is there a possibility to replace any line feed character with a space or nothing?
>> I think this should be done in the pyasn1 module, but I don't know how.
>>
>> Hope somebody can help me with my problem.
>>
>> Kind regards,
>> Tom
>>
>
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