AgentX

This is fork of go-agentx library with traps support.

A library with a pure Go implementation of the AgentX-Protocol. The library is not yet feature-complete, but should be far enough to used in a production environment.

The AgentX-Protocol can be used to extend a snmp-daemon such that it dispatches the requests to an OID-subtree to your Go application. Those requests are than handled by this library and can be replied with metrics about your applications state.

State

The library implements all variable types (Integer, OctetString, Null, ObjectIdentifier, IPAddress, Counter32, Gauge32, TimeTicks, Opaque, Counter64, NoSuchObject, NoSuchInstance, EndOfMIBView), but only some of the requests (Get, GetNext, GetBulk, Notify). Set-requests are not implemented yet.

Helper

In order to provided metrics, your have to implement the agentx.Handler interface. For convenience, you can use the agentx.ListHandler implementation, which takes a list of OIDs and values and serves them if requested. An example is listed below.

Example

package main

import (
	"log"
	"net"
	"time"

	"gopkg.in/errgo.v1"

	"github.com/vadimipatov/go-agentx"
	"github.com/vadimipatov/go-agentx/pdu"
	"github.com/vadimipatov/go-agentx/value"
)

func main() {
	client := &agentx.Client{
		Net:               "tcp",
		Address:           "localhost:705",
		Timeout:           1 * time.Minute,
		ReconnectInterval: 1 * time.Second,
	}

	if err := client.Open(); err != nil {
		log.Fatalf(errgo.Details(err))
	}

	session, err := client.Session()
	if err != nil {
		log.Fatalf(errgo.Details(err))
	}

	listHandler := &agentx.ListHandler{}

	item := listHandler.Add("1.3.6.1.4.1.45995.3.1")
	item.Type = pdu.VariableTypeInteger
	item.Value = int32(-123)

	item = listHandler.Add("1.3.6.1.4.1.45995.3.2")
	item.Type = pdu.VariableTypeOctetString
	item.Value = "echo test"

	item = listHandler.Add("1.3.6.1.4.1.45995.3.3")
	item.Type = pdu.VariableTypeNull
	item.Value = nil

	item = listHandler.Add("1.3.6.1.4.1.45995.3.4")
	item.Type = pdu.VariableTypeObjectIdentifier
	item.Value = "1.3.6.1.4.1.45995.1.5"

	item = listHandler.Add("1.3.6.1.4.1.45995.3.5")
	item.Type = pdu.VariableTypeIPAddress
	item.Value = net.IP{10, 10, 10, 10}

	item = listHandler.Add("1.3.6.1.4.1.45995.3.6")
	item.Type = pdu.VariableTypeCounter32
	item.Value = uint32(123)

	item = listHandler.Add("1.3.6.1.4.1.45995.3.7")
	item.Type = pdu.VariableTypeGauge32
	item.Value = uint32(123)

	item = listHandler.Add("1.3.6.1.4.1.45995.3.8")
	item.Type = pdu.VariableTypeTimeTicks
	item.Value = 123 * time.Second

	item = listHandler.Add("1.3.6.1.4.1.45995.3.9")
	item.Type = pdu.VariableTypeOpaque
	item.Value = []byte{1, 2, 3}

	item = listHandler.Add("1.3.6.1.4.1.45995.3.10")
	item.Type = pdu.VariableTypeCounter64
	item.Value = uint64(12345678901234567890)

	session.Handler = listHandler

	if err := session.Register(127, value.MustParseOID("1.3.6.1.4.1.45995.3")); err != nil {
		log.Fatalf(errgo.Details(err))
	}

	var payload pdu.Variables
	TrapOID := "1.3.6.1.4.1.45995.3"
	payload.Add(value.MustParseOID("1.3.6.1.2.1.1.3.0"), pdu.VariableTypeTimeTicks, time.Since(startTime)) // uptime
	payload.Add(value.MustParseOID("1.3.6.1.6.3.1.1.4.1.0"), pdu.VariableTypeObjectIdentifier, "1.3.6.1.6.3.1.1.4.3.0."+TrapOID) // SNMPTRAP -> ENTERPRISE.OID
		payload.Add(value.MustParseOID(TrapOID+".11), pdu.VariableTypeInteger, int32(42))

	if err := session.Notify(payload); err != nil {
		log.Fatalf(errgo.Details(err))
	}

	for {
		time.Sleep(100 * time.Millisecond)
	}
}

Connection lost

If the connection to the snmp-daemon is lost, the client tries to reconnect. Therefor the property ReconnectInterval has be set. It specifies a duration that is waited before a re-connect is tried. If the client has open session or registrations, the client try to re-establish both on a successful re-connect.

Known issues

Unmarshalling of response variables is not working properly and temporarily disabled

Project

The implementation was provided by simia.tech GbR.

License

The project is licensed under LGPL (see LICENSE file).