Handle snmp traps and informs on localhost using node js

Question

I am trying to listen for snmp traps on the standard UDP 162 port and then parse and output them.

I have looked at snmpjs and snmp-native plugins for node and they both seem to major on the generation of agents. What I would like to do is listen and decode traps and informs that are forwarded to my localhost (maybe even acknowledge informs). I know I could spend quite some time with dgram and ASN.1BER but would prefer to use already written snmp code.

var dgram = require('dgram');
//var snmp = require('snmpjs');
var snmp = require('snmp-native');

var server = dgram.createSocket("udp4");

server.on("listening", function() {
    var addr = server.address();
    console.log("Server listening "+ addr.address + ":" + addr.port);
});

server.on("message", function (msg, rinfo) {
    console.log("From " + rinfo.address + ":" + rinfo.port);
    console.log("server got: " + msg);
    //console.log("Parse: " + snmp.parseMessage({raw:msg}));
    console.log("Parse: " + snmp.parse(msg));
});

server.bind(162);

Both snmp parse functions cause errors, the first is parseMessage not defined, and it's not clear in the snmpjs documents how to create the correct object http://wesolows.github.com/node-snmpjs/protocol.html#parseMessage(arg). And I can't use the snmpjs agent as there is no on message event.

The second parse from snmp-native, I get an error that the buffer is not an int....

Error: Buffer 06082b06010603010105 does not appear to be an Integer
at Object.parseInteger (/usr/share/node/node_modules/snmp-native/lib/asn1ber.js:318:15)

Any pointers would be great, thanks.

Answer 1

node-snmpjs 0.0.4 now contains a simple trap listener that emits events on traps. An Express-style interface could be added very easily to match what the Agent does. See the GitHub commit adding this functionality for an example consumer. More work will be needed to make this suitable for production use.