GoSNMPServer

go install github.com/slayercat/GoSNMPServer/cmd/gosnmpserver
$(go env GOPATH)/bin/gosnmpserver run-server
snmpwalk -v 3 -l authPriv  -n public -u testuser   -a md5 -A testauth -x des -X testpriv 127.0.0.1:1161 1

import "github.com/slayercat/gosnmp"
import "github.com/slayercat/GoSNMPServer"
import "github.com/slayercat/GoSNMPServer/mibImps"

master := GoSNMPServer.MasterAgent{
    Logger: GoSNMPServer.NewDefaultLogger(),
    SecurityConfig: GoSNMPServer.SecurityConfig{
        AuthoritativeEngineBoots: 1,
        Users: []gosnmp.UsmSecurityParameters{
            {
                UserName:                 c.String("v3Username"),
                AuthenticationProtocol:   gosnmp.MD5,
                PrivacyProtocol:          gosnmp.DES,
                AuthenticationPassphrase: c.String("v3AuthenticationPassphrase"),
                PrivacyPassphrase:        c.String("v3PrivacyPassphrase"),
            },
        },
    },
    SubAgents: []*GoSNMPServer.SubAgent{
        {
            CommunityIDs: []string{c.String("community")},
            OIDs:         mibImps.All(),
        },
    },
}
server := GoSNMPServer.NewSNMPServer(master)
err := server.ListenUDP("udp", "127.0.0.1:1161")
if err != nil {
    logger.Errorf("Error in listen: %+v", err)
}
server.ServeForever()

{
    OID:      fmt.Sprintf("1.3.6.1.2.1.2.2.1.1.%d", ifIndex),
    Type:     gosnmp.Integer,
    OnGet:    func() (value interface{}, err error) { return GoSNMPServer.Asn1IntegerWrap(ifIndex), nil },
    Document: "ifIndex",
},