telegraf/plugins/inputs/snmp/snmp.go

625 lines
16 KiB
Go

package snmp
import (
"fmt"
"math"
"net"
"strconv"
"strings"
"time"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/plugins/inputs"
"github.com/soniah/gosnmp"
)
const description = `Retrieves SNMP values from remote agents`
const sampleConfig = `
agents = [ "127.0.0.1:161" ]
version = 2 # Values: 1, 2, or 3
## SNMPv1 & SNMPv2 parameters
community = "public"
## SNMPv2 & SNMPv3 parameters
max_repetitions = 50
## SNMPv3 parameters
#sec_name = "myuser"
#auth_protocol = "md5" # Values: "MD5", "SHA", ""
#auth_password = "password123"
#sec_level = "authNoPriv" # Values: "noAuthNoPriv", "authNoPriv", "authPriv"
#context_name = ""
#priv_protocol = "" # Values: "DES", "AES", ""
#priv_password = ""
## measurement name
name = "system"
[[inputs.snmp.field]]
name = "hostname"
oid = ".1.2.3.0.1.1"
[[inputs.snmp.field]]
name = "uptime"
oid = ".1.2.3.0.1.200"
[[inputs.snmp.field]]
name = "load"
oid = ".1.2.3.0.1.201"
[[inputs.snmp.table]]
# measurement name
name = "remote_servers"
inherit_tags = [ "hostname" ]
[[inputs.snmp.table.field]]
name = "server"
oid = ".1.2.3.0.0.0"
is_tag = true
[[inputs.snmp.table.field]]
name = "connections"
oid = ".1.2.3.0.0.1"
[[inputs.snmp.table.field]]
name = "latency"
oid = ".1.2.3.0.0.2"
`
// Snmp holds the configuration for the plugin.
type Snmp struct {
// The SNMP agent to query. Format is ADDR[:PORT] (e.g. 1.2.3.4:161).
Agents []string
// Timeout to wait for a response. Value is anything accepted by time.ParseDuration().
Timeout string
Retries int
// Values: 1, 2, 3
Version uint8
// Parameters for Version 1 & 2
Community string
// Parameters for Version 2 & 3
MaxRepetitions uint
// Parameters for Version 3
ContextName string
// Values: "noAuthNoPriv", "authNoPriv", "authPriv"
SecLevel string
SecName string
// Values: "MD5", "SHA", "". Default: ""
AuthProtocol string
AuthPassword string
// Values: "DES", "AES", "". Default: ""
PrivProtocol string
PrivPassword string
EngineID string
EngineBoots uint32
EngineTime uint32
Tables []Table `toml:"table"`
// Name & Fields are the elements of a Table.
// Telegraf chokes if we try to embed a Table. So instead we have to embed the
// fields of a Table, and construct a Table during runtime.
Name string
Fields []Field `toml:"field"`
connectionCache map[string]snmpConnection
}
// Table holds the configuration for a SNMP table.
type Table struct {
// Name will be the name of the measurement.
Name string
// Which tags to inherit from the top-level config.
InheritTags []string
// Fields is the tags and values to look up.
Fields []Field `toml:"field"`
}
// Field holds the configuration for a Field to look up.
type Field struct {
// Name will be the name of the field.
Name string
// OID is prefix for this field. The plugin will perform a walk through all
// OIDs with this as their parent. For each value found, the plugin will strip
// off the OID prefix, and use the remainder as the index. For multiple fields
// to show up in the same row, they must share the same index.
Oid string
// IsTag controls whether this OID is output as a tag or a value.
IsTag bool
// Conversion controls any type conversion that is done on the value.
// "float"/"float(0)" will convert the value into a float.
// "float(X)" will convert the value into a float, and then move the decimal before Xth right-most digit.
// "int" will conver the value into an integer.
Conversion string
}
// RTable is the resulting table built from a Table.
type RTable struct {
// Name is the name of the field, copied from Table.Name.
Name string
// Time is the time the table was built.
Time time.Time
// Rows are the rows that were found, one row for each table OID index found.
Rows []RTableRow
}
// RTableRow is the resulting row containing all the OID values which shared
// the same index.
type RTableRow struct {
// Tags are all the Field values which had IsTag=true.
Tags map[string]string
// Fields are all the Field values which had IsTag=false.
Fields map[string]interface{}
}
// Errors is a list of errors accumulated during an interval.
type Errors []error
func (errs Errors) Error() string {
s := ""
for _, err := range errs {
if s == "" {
s = err.Error()
} else {
s = s + ". " + err.Error()
}
}
return s
}
// NestedError wraps an error returned from deeper in the code.
type NestedError struct {
// Err is the error from where the NestedError was constructed.
Err error
// NestedError is the error that was passed back from the called function.
NestedErr error
}
// Error returns a concatenated string of all the nested errors.
func (ne NestedError) Error() string {
return ne.Err.Error() + ": " + ne.NestedErr.Error()
}
// Errorf is a convenience function for constructing a NestedError.
func Errorf(err error, msg string, format ...interface{}) error {
return NestedError{
NestedErr: err,
Err: fmt.Errorf(msg, format...),
}
}
func init() {
inputs.Add("snmp", func() telegraf.Input {
return &Snmp{
Retries: 5,
MaxRepetitions: 50,
}
})
}
// SampleConfig returns the default configuration of the input.
func (s *Snmp) SampleConfig() string {
return sampleConfig
}
// Description returns a one-sentence description on the input.
func (s *Snmp) Description() string {
return description
}
// Gather retrieves all the configured fields and tables.
// Any error encountered does not halt the process. The errors are accumulated
// and returned at the end.
func (s *Snmp) Gather(acc telegraf.Accumulator) error {
var errs Errors
for _, agent := range s.Agents {
gs, err := s.getConnection(agent)
if err != nil {
errs = append(errs, Errorf(err, "agent %s", agent))
continue
}
// First is the top-level fields. We treat the fields as table prefixes with an empty index.
t := Table{
Name: s.Name,
Fields: s.Fields,
}
topTags := map[string]string{}
if err := s.gatherTable(acc, gs, t, topTags, false); err != nil {
errs = append(errs, Errorf(err, "agent %s", agent))
}
// Now is the real tables.
for _, t := range s.Tables {
if err := s.gatherTable(acc, gs, t, topTags, true); err != nil {
errs = append(errs, Errorf(err, "agent %s", agent))
}
}
}
if errs == nil {
return nil
}
return errs
}
func (s *Snmp) gatherTable(acc telegraf.Accumulator, gs snmpConnection, t Table, topTags map[string]string, walk bool) error {
rt, err := t.Build(gs, walk)
if err != nil {
return err
}
for _, tr := range rt.Rows {
if !walk {
// top-level table. Add tags to topTags.
for k, v := range tr.Tags {
topTags[k] = v
}
} else {
// real table. Inherit any specified tags.
for _, k := range t.InheritTags {
if v, ok := topTags[k]; ok {
tr.Tags[k] = v
}
}
}
if _, ok := tr.Tags["agent_host"]; !ok {
tr.Tags["agent_host"] = gs.Host()
}
acc.AddFields(rt.Name, tr.Fields, tr.Tags, rt.Time)
}
return nil
}
// Build retrieves all the fields specified in the table and constructs the RTable.
func (t Table) Build(gs snmpConnection, walk bool) (*RTable, error) {
rows := map[string]RTableRow{}
tagCount := 0
for _, f := range t.Fields {
if f.IsTag {
tagCount++
}
if len(f.Oid) == 0 {
return nil, fmt.Errorf("cannot have empty OID")
}
var oid string
if f.Oid[0] == '.' {
oid = f.Oid
} else {
// make sure OID has "." because the BulkWalkAll results do, and the prefix needs to match
oid = "." + f.Oid
}
// ifv contains a mapping of table OID index to field value
ifv := map[string]interface{}{}
if !walk {
// This is used when fetching non-table fields. Fields configured a the top
// scope of the plugin.
// We fetch the fields directly, and add them to ifv as if the index were an
// empty string. This results in all the non-table fields sharing the same
// index, and being added on the same row.
if pkt, err := gs.Get([]string{oid}); err != nil {
return nil, Errorf(err, "performing get")
} else if pkt != nil && len(pkt.Variables) > 0 && pkt.Variables[0].Type != gosnmp.NoSuchObject {
ent := pkt.Variables[0]
ifv[ent.Name[len(oid):]] = fieldConvert(f.Conversion, ent.Value)
}
} else {
err := gs.Walk(oid, func(ent gosnmp.SnmpPDU) error {
if len(ent.Name) <= len(oid) || ent.Name[:len(oid)+1] != oid+"." {
return NestedError{} // break the walk
}
ifv[ent.Name[len(oid):]] = fieldConvert(f.Conversion, ent.Value)
return nil
})
if err != nil {
if _, ok := err.(NestedError); !ok {
return nil, Errorf(err, "performing bulk walk")
}
}
}
for i, v := range ifv {
rtr, ok := rows[i]
if !ok {
rtr = RTableRow{}
rtr.Tags = map[string]string{}
rtr.Fields = map[string]interface{}{}
rows[i] = rtr
}
if f.IsTag {
if vs, ok := v.(string); ok {
rtr.Tags[f.Name] = vs
} else {
rtr.Tags[f.Name] = fmt.Sprintf("%v", v)
}
} else {
rtr.Fields[f.Name] = v
}
}
}
rt := RTable{
Name: t.Name,
Time: time.Now(), //TODO record time at start
Rows: make([]RTableRow, 0, len(rows)),
}
for _, r := range rows {
if len(r.Tags) < tagCount {
// don't add rows which are missing tags, as without tags you can't filter
continue
}
rt.Rows = append(rt.Rows, r)
}
return &rt, nil
}
// snmpConnection is an interface which wraps a *gosnmp.GoSNMP object.
// We interact through an interface so we can mock it out in tests.
type snmpConnection interface {
Host() string
//BulkWalkAll(string) ([]gosnmp.SnmpPDU, error)
Walk(string, gosnmp.WalkFunc) error
Get(oids []string) (*gosnmp.SnmpPacket, error)
}
// gosnmpWrapper wraps a *gosnmp.GoSNMP object so we can use it as a snmpConnection.
type gosnmpWrapper struct {
*gosnmp.GoSNMP
}
// Host returns the value of GoSNMP.Target.
func (gsw gosnmpWrapper) Host() string {
return gsw.Target
}
// Walk wraps GoSNMP.Walk() or GoSNMP.BulkWalk(), depending on whether the
// connection is using SNMPv1 or newer.
// Also, if any error is encountered, it will just once reconnect and try again.
func (gsw gosnmpWrapper) Walk(oid string, fn gosnmp.WalkFunc) error {
var err error
// On error, retry once.
// Unfortunately we can't distinguish between an error returned by gosnmp, and one returned by the walk function.
for i := 0; i < 2; i++ {
if gsw.Version == gosnmp.Version1 {
err = gsw.GoSNMP.Walk(oid, fn)
} else {
err = gsw.GoSNMP.BulkWalk(oid, fn)
}
if err == nil {
return nil
}
if err := gsw.GoSNMP.Connect(); err != nil {
return Errorf(err, "reconnecting")
}
}
return err
}
// Get wraps GoSNMP.GET().
// If any error is encountered, it will just once reconnect and try again.
func (gsw gosnmpWrapper) Get(oids []string) (*gosnmp.SnmpPacket, error) {
var err error
var pkt *gosnmp.SnmpPacket
for i := 0; i < 2; i++ {
pkt, err = gsw.GoSNMP.Get(oids)
if err == nil {
return pkt, nil
}
if err := gsw.GoSNMP.Connect(); err != nil {
return nil, Errorf(err, "reconnecting")
}
}
return nil, err
}
// getConnection creates a snmpConnection (*gosnmp.GoSNMP) object and caches the
// result using `agent` as the cache key.
func (s *Snmp) getConnection(agent string) (snmpConnection, error) {
if s.connectionCache == nil {
s.connectionCache = map[string]snmpConnection{}
}
if gs, ok := s.connectionCache[agent]; ok {
return gs, nil
}
gs := gosnmpWrapper{&gosnmp.GoSNMP{}}
host, portStr, err := net.SplitHostPort(agent)
if err != nil {
if err, ok := err.(*net.AddrError); !ok || err.Err != "missing port in address" {
return nil, Errorf(err, "parsing host")
}
host = agent
portStr = "161"
}
gs.Target = host
port, err := strconv.ParseUint(portStr, 10, 16)
if err != nil {
return nil, Errorf(err, "parsing port")
}
gs.Port = uint16(port)
if s.Timeout != "" {
if gs.Timeout, err = time.ParseDuration(s.Timeout); err != nil {
return nil, Errorf(err, "parsing timeout")
}
} else {
gs.Timeout = time.Second * 1
}
gs.Retries = s.Retries
switch s.Version {
case 3:
gs.Version = gosnmp.Version3
case 2, 0:
gs.Version = gosnmp.Version2c
case 1:
gs.Version = gosnmp.Version1
default:
return nil, fmt.Errorf("invalid version")
}
if s.Version < 3 {
if s.Community == "" {
gs.Community = "public"
} else {
gs.Community = s.Community
}
}
gs.MaxRepetitions = int(s.MaxRepetitions)
if s.Version == 3 {
gs.ContextName = s.ContextName
sp := &gosnmp.UsmSecurityParameters{}
gs.SecurityParameters = sp
gs.SecurityModel = gosnmp.UserSecurityModel
switch strings.ToLower(s.SecLevel) {
case "noauthnopriv", "":
gs.MsgFlags = gosnmp.NoAuthNoPriv
case "authnopriv":
gs.MsgFlags = gosnmp.AuthNoPriv
case "authpriv":
gs.MsgFlags = gosnmp.AuthPriv
default:
return nil, fmt.Errorf("invalid secLevel")
}
sp.UserName = s.SecName
switch strings.ToLower(s.AuthProtocol) {
case "md5":
sp.AuthenticationProtocol = gosnmp.MD5
case "sha":
sp.AuthenticationProtocol = gosnmp.SHA
case "":
sp.AuthenticationProtocol = gosnmp.NoAuth
default:
return nil, fmt.Errorf("invalid authProtocol")
}
sp.AuthenticationPassphrase = s.AuthPassword
switch strings.ToLower(s.PrivProtocol) {
case "des":
sp.PrivacyProtocol = gosnmp.DES
case "aes":
sp.PrivacyProtocol = gosnmp.AES
case "":
sp.PrivacyProtocol = gosnmp.NoPriv
default:
return nil, fmt.Errorf("invalid privProtocol")
}
sp.PrivacyPassphrase = s.PrivPassword
sp.AuthoritativeEngineID = s.EngineID
sp.AuthoritativeEngineBoots = s.EngineBoots
sp.AuthoritativeEngineTime = s.EngineTime
}
if err := gs.Connect(); err != nil {
return nil, Errorf(err, "setting up connection")
}
s.connectionCache[agent] = gs
return gs, nil
}
// fieldConvert converts from any type according to the conv specification
// "float"/"float(0)" will convert the value into a float.
// "float(X)" will convert the value into a float, and then move the decimal before Xth right-most digit.
// "int" will convert the value into an integer.
// "" will convert a byte slice into a string.
// Any other conv will return the input value unchanged.
func fieldConvert(conv string, v interface{}) interface{} {
if conv == "" {
if bs, ok := v.([]byte); ok {
return string(bs)
}
return v
}
var d int
if _, err := fmt.Sscanf(conv, "float(%d)", &d); err == nil || conv == "float" {
switch vt := v.(type) {
case float32:
v = float64(vt) / math.Pow10(d)
case float64:
v = float64(vt) / math.Pow10(d)
case int:
v = float64(vt) / math.Pow10(d)
case int8:
v = float64(vt) / math.Pow10(d)
case int16:
v = float64(vt) / math.Pow10(d)
case int32:
v = float64(vt) / math.Pow10(d)
case int64:
v = float64(vt) / math.Pow10(d)
case uint:
v = float64(vt) / math.Pow10(d)
case uint8:
v = float64(vt) / math.Pow10(d)
case uint16:
v = float64(vt) / math.Pow10(d)
case uint32:
v = float64(vt) / math.Pow10(d)
case uint64:
v = float64(vt) / math.Pow10(d)
case []byte:
vf, _ := strconv.ParseFloat(string(vt), 64)
v = vf / math.Pow10(d)
case string:
vf, _ := strconv.ParseFloat(vt, 64)
v = vf / math.Pow10(d)
}
}
if conv == "int" {
switch vt := v.(type) {
case float32:
v = int64(vt)
case float64:
v = int64(vt)
case int:
v = int64(vt)
case int8:
v = int64(vt)
case int16:
v = int64(vt)
case int32:
v = int64(vt)
case int64:
v = int64(vt)
case uint:
v = int64(vt)
case uint8:
v = int64(vt)
case uint16:
v = int64(vt)
case uint32:
v = int64(vt)
case uint64:
v = int64(vt)
case []byte:
v, _ = strconv.Atoi(string(vt))
case string:
v, _ = strconv.Atoi(vt)
}
}
return v
}