What should be the type given to self.agent.OctetString ?

[kabassanov]

Hi,

Could you, please give me a working example of OctetString assignment?

I tried different variable types (from bytearray, through its hex() representation to ordinary string, but always got errors with self.agent.OctetString(var)?

Thanks a lot.

[kgraefe]

It should be a bytes (e.g. b"kabassanov") object, but OctetString was kinda borked before #40 and that is merged but not yet released... (probably never will be)

[kgraefe]

Oh, and here is an incomplete example how I used it in the past (with #40 included):

def iface_hex_buf(*args):
    fname = os.path.join("/sys/class/net", *args)
    with open(fname, "r") as f:
        val = f.read().strip()
    return val.replace(":", "").replace(".", "").decode("hex")

class BridgeAgent(netsnmpagent.netsnmpAgent):
    def __init__(self, *args, **kwargs):
        super(BridgeAgent, self).__init__(
            AgentName = "BridgeAgent",
            *args, **kwargs
        )
        ....
        self._bridgeAddr = self.OctetString(
            oidstr = "BRIDGE-MIB::dot1dBaseBridgeAddress"
        )

   def _set_defaults(self):
      ....
      self._bridgeAddr.update(bytes())

   def update(self):
      ....
      self._bridgeAddr.update(iface_hex_buf(bridge, "address"))

[kabassanov]

Thank you, @kgraefe.

I try to fill some oids of type :

PortList ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"Each octet within this value specifies a set of eight
ports, with the first octet specifying ports 1 through
8, the second octet specifying ports 9 through 16, etc.
Within each octet, the most significant bit represents
the lowest numbered port, and the least significant bit
represents the highest numbered port. Thus, each port
of the bridge is represented by a single bit within the
value of this object. If that bit has a value of '1',
then that port is included in the set of ports; the port
is not included if its bit has a value of '0'."
SYNTAX OCTET STRING

I managed to fill a bytearray(8) structure called ifaceMap with corresponding values, but now the issue is to send to the agent...

        tmpVlan.setRowCell(
            4,
            self.agent.OctetString(bytes(ifaceMap))
        )

raises

File "/usr/lib/python3/dist-packages/netsnmpagent.py", line 774, in setRowCell
raise netsnmpAgentException("netsnmp_set_row_column() failed with error code {0}!".format(result))
netsnmpagent.netsnmpAgentException: netsnmp_set_row_column() failed with error code -1!

It could be effectively related to NUL bytes...