node-snmp

Binding for Net-SNMP library, and simple wrapper to make life a bit easier.

Features

So far only snmp queries and protocol V1 are supported. It has both synchronous and asynchronous interface, but the former requires libev compiled with support for multiple event loops. As stock node is by default compiled without this, only asynchronous queries are usually available - unless you compile node binary yourself.

Dependencies

Net-SNMP library - tested with version 5.4.3

Build

1. node-waf configure build
2. copy snmp.js and build/default/snmp_binding.node somewhere where node can find them:
   • ~/.node_libraries
   • \<your_project_root>/node_modules/snmp (copy package.json too when using this variant)

See http://nodejs.org/docs/v0.4.7/api/modules.html for details.

Eventually, "npm install -g" should do the trick too, but I can't seem to get it to work right now.

Build .deb package

$ # git clone <url>
$ git branch debian origin/debian
$ git-buildpackage --git-upstream-branch=master --git-debian-branch=debian --git-force-create -us -uc

At present, you need nodejs-dev package from debian/sid repository to build. git-buildpackage is optional, debian has several options, but I found this to be the easiest way.

API

callbacks

all callbacks are called with fairly standard (error, data) arguments.

Error can be used as boolean false when query finished successfully, Error object with error description otherwise (convertible to String).

Data is array of objects with 'value' and 'oid' properties, both of them of type Value:

    [
        { oid: ..., value: ... },
        { oid: ..., value: ... }
    ]

Value - no public constructor

• toArray, toString - return some aproximation of contained data, similar to what snmpwalk does
• GetData - return raw data in several possible formats - see toArray implementation for details
• GetType - one of SnmpValue.[VT_NUMBER, VT_TEXT, VT_OID, VT_RAW, VT_NULL] Remnant of early design, probably useless, could be removed in the future

Error - no public constructor

• toString()
• isEof() - used internally by GetSubtree

Connection(host, community)

• Get, GetNext - map directly to corresponding SNMP operations, take OID (in any format) or array of OIDs (only as array of integers) and callback arguments
• GetSubtree - use getNext to walk whole subtree of starting OID

free functions in exports:

• read_objid - parse dotted oid string into array of integers
• parse_oid - parse any string to array of integers (including MIB translation)

Usage example

var conn = new (require('snmp').cSnmpConnection)("localhost", "public");
conn.get(".1.3.6.1.2.1.1.1", function(aError, aData) {
  console.log(aData[0].value.toString());
  });

see examples/ directory for more complete sample

TODO

(in no particular order)

• support for V2 and V3 protocols, bulk queries
• support TRAP operation
• support conversion from OID to MIB symbolic name
• make the package npm-compatible (npm link works, npm install does not)
• find out why example doesn't work when copy/pasted to node cmdline, it must be run from file on disk
• cleanup the C++ code (memory leaks in error code paths)