way to get opaque data ?

[cmpetty]

is there a way to get/set opaque values?

For instance here's a few snippets from calling the snmp command line tools:

snmptranslate -On -Td WIENER-CRATE-MIB::outputVoltage
.1.3.6.1.4.1.19947.1.3.2.1.10
outputVoltage OBJECT-TYPE
  -- FROM   WIENER-CRATE-MIB
  -- TEXTUAL CONVENTION Float
  SYNTAX    Opaque (WIENER-CRATE-MIB) 
  UNITS     "V"
  MAX-ACCESS    read-write
  STATUS    current
  DESCRIPTION   "The nominal output voltage of the channel."

Pull the value:

snmpget -v 2c -m +WIENER-CRATE-MIB -c public localhost outputVoltage.u0
WIENER-CRATE-MIB::outputVoltage.u0 = Opaque: Float: 8.000000 V

Set the value as a float:

snmpset -v 2c -m +WIENER-CRATE-MIB -c higher localhost outputVoltage.u0 F 8
WIENER-CRATE-MIB::outputVoltage.u0 = Opaque: Float: 8.000000 V

When i try to do the same thing via python and easysnmp, i get a "wrongEncoding" error if i try float.

And if i do a walk snmp_type is empty, along with all the values:

session.walk('WIENER-CRATE-MIB::outputVoltage')
Out[29]:
SNMPVariable value='' (oid='outputVoltage', oid_index='1', snmp_type='')
SNMPVariable value='' (oid='outputVoltage', oid_index='2', snmp_type='')
SNMPVariable value='' (oid='outputVoltage', oid_index='3', snmp_type='')
SNMPVariable value='' (oid='outputVoltage', oid_index='4', snmp_type='')

Even though i know they are set from the command line version of walk:

snmpwalk -v 2c -m +WIENER-CRATE-MIB -c public localhost outputVoltage
WIENER-CRATE-MIB::outputVoltage.u0 = Opaque: Float: 8.000000 V
WIENER-CRATE-MIB::outputVoltage.u1 = Opaque: Float: 8.000000 V
WIENER-CRATE-MIB::outputVoltage.u2 = Opaque: Float: 8.000000 V
WIENER-CRATE-MIB::outputVoltage.u3 = Opaque: Float: 8.000000 V
WIENER-CRATE-MIB::outputVoltage.u4 = Opaque: Float: 8.000000 V

I had to assume this is from the Opaque part of the data because i can get/set INTEGERS normally:

In [30]: session.set('WIENER-CRATE-MIB::outputSwitch.1','0',snmp_type='i')
Out[30]: True
In [31]: session.get('WIENER-CRATE-MIB::outputSwitch.1')
Out[31]: <SNMPVariable value='0' (oid='outputSwitch', oid_index='1', snmp_type='INTEGER')>

Any help is appreciated because this seems the logical way of moving forward rather than reaching out to snmpset with subprocess. Thanks.

[samibrahiem]

I am facing the same problem, when I try getting Opaque type OID, I only get the tag. The rest of the values (iid,val and type) are set to "None". Is there a way to read these OIDs through EasySNMP?

[cmpetty]

i never found a way through easysnmp to get/set opaques.

i used pysnmp to get them, but then had to covert them .. here's a sample:

from pysnmp.entity.rfc3413.oneliner import cmdgen 

cmdGen = cmdgen.CommandGenerator()
     cmdgen.UdpTransportTarget((crateip, 161)),
                                                                            '1.3.6.1.4.1.19947.1.3.2.1.12', #outputCurrent
                                                                            '1.3.6.1.4.1.19947.1.3.2.1.10', #outputVoltage
                                                                            '1.3.6.1.4.1.19947.1.3.2.1.7', #outputMeasurementCurrent
                                                                            )

        currdata = []
        currtime = time.time()

        for var in varBinds:
            for sv in var:
                oidsplit = sv[0].getOid().prettyPrint().split('.')
                chanidx = oidsplit[-1]
                oid_noidx = '.'.join(oidsplit[:-1])
                name = mibLUT[oid_noidx]

                if re.search('opaque',sv[-1].prettyPrintType(),re.IGNORECASE):
                    outval = struct.unpack('>f',sv[-1].asOctets()[3:])[0]
                else:
                    outval = sv[-1]._value
                currdata.append([currtime, name, outval, chanidx ])

        thisdf = pd.DataFrame(currdata,columns=['measurementTime','measurementType','measurementValue','channel'])

[samibrahiem]

Thank you for sharing Chris! :)