fix: Add option to select translator (#10802)

agent/agent.go

@@ -13,6 +13,7 @@ import (
 	"github.com/influxdata/telegraf"
 	"github.com/influxdata/telegraf/config"
 	"github.com/influxdata/telegraf/internal"
+	"github.com/influxdata/telegraf/internal/snmp"
 	"github.com/influxdata/telegraf/models"
 	"github.com/influxdata/telegraf/plugins/serializers/influx"
 )
@@ -186,6 +187,10 @@ func (a *Agent) Run(ctx context.Context) error {
 // initPlugins runs the Init function on plugins.
 func (a *Agent) initPlugins() error {
 	for _, input := range a.Config.Inputs {
+		// Share the snmp translator setting with plugins that need it.
+		if tp, ok := input.Input.(snmp.TranslatorPlugin); ok {
+			tp.SetTranslator(a.Config.Agent.Translator)
+		}
 		err := input.Init()
 		if err != nil {
 			return fmt.Errorf("could not initialize input %s: %v",

config/config.go

@@ -225,6 +225,8 @@ type AgentConfig struct {
 
 	Hostname     string
 	OmitHostname bool
+
+	Translator string `toml:"translator"`
 }
 
 // InputNames returns a list of strings of the configured inputs.
@@ -418,6 +420,11 @@ var agentConfig = `
   hostname = ""
   ## If set to true, do no set the "host" tag in the telegraf agent.
   omit_hostname = false
+
+  ## Translator for SNMP OIDs
+  ## Valid values are "netsnmp" which runs snmptranslate and snmptable,
+  ## and "gosmi" which uses the gosmi library.
+  # translator = "netsnmp"
 `
 
 var outputHeader = `
@@ -855,6 +862,11 @@ func (c *Config) LoadConfigData(data []byte) error {
 		c.Tags["host"] = c.Agent.Hostname
 	}
 
+	// Set snmp agent translator default
+	if c.Agent.Translator == "" {
+		c.Agent.Translator = "netsnmp"
+	}
+
 	if len(c.UnusedFields) > 0 {
 		return fmt.Errorf("line %d: configuration specified the fields %q, but they weren't used", tbl.Line, keys(c.UnusedFields))
 	}

internal/snmp/config.go

@@ -12,6 +12,8 @@ type ClientConfig struct {
 	Version uint8 `toml:"version"`
 	// Path to mib files
 	Path []string `toml:"path"`
+	// Translator implementation
+	Translator string `toml:"-"`
 
 	// Parameters for Version 1 & 2
 	Community string `toml:"community"`

internal/snmp/translator.go

@@ -0,0 +1,5 @@
+package snmp
+
+type TranslatorPlugin interface {
+	SetTranslator(name string) // Agent calls this on inputs before Init
+}

plugins/inputs/snmp/README.md

@@ -30,6 +30,8 @@ path onto the global path variable
   # version = 2
 
   ## Path to mib files
+  ## Used by the gosmi translator.
+  ## To add paths when translating with netsnmp, use the MIBDIRS environment variable
   # path = ["/usr/share/snmp/mibs"]
 
   ## SNMP community string.

plugins/inputs/snmp/gosmi.go

@@ -0,0 +1,123 @@
+package snmp
+
+import (
+	"fmt"
+	"sync"
+
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/internal/snmp"
+	"github.com/sleepinggenius2/gosmi"
+)
+
+type gosmiTranslator struct {
+}
+
+func NewGosmiTranslator(paths []string, log telegraf.Logger) (*gosmiTranslator, error) {
+	err := snmp.LoadMibsFromPath(paths, log, &snmp.GosmiMibLoader{})
+	if err == nil {
+		return &gosmiTranslator{}, nil
+	}
+	return nil, err
+}
+
+type gosmiSnmpTranslateCache struct {
+	mibName    string
+	oidNum     string
+	oidText    string
+	conversion string
+	node       gosmi.SmiNode
+	err        error
+}
+
+var gosmiSnmpTranslateCachesLock sync.Mutex
+var gosmiSnmpTranslateCaches map[string]gosmiSnmpTranslateCache
+
+//nolint:revive
+func (g *gosmiTranslator) SnmpTranslate(oid string) (string, string, string, string, error) {
+	a, b, c, d, _, e := g.SnmpTranslateFull(oid)
+	return a, b, c, d, e
+}
+
+//nolint:revive
+func (g *gosmiTranslator) SnmpTranslateFull(oid string) (
+	mibName string, oidNum string, oidText string,
+	conversion string,
+	node gosmi.SmiNode,
+	err error) {
+	gosmiSnmpTranslateCachesLock.Lock()
+	if gosmiSnmpTranslateCaches == nil {
+		gosmiSnmpTranslateCaches = map[string]gosmiSnmpTranslateCache{}
+	}
+
+	var stc gosmiSnmpTranslateCache
+	var ok bool
+	if stc, ok = gosmiSnmpTranslateCaches[oid]; !ok {
+		// This will result in only one call to snmptranslate running at a time.
+		// We could speed it up by putting a lock in snmpTranslateCache and then
+		// returning it immediately, and multiple callers would then release the
+		// snmpTranslateCachesLock and instead wait on the individual
+		// snmpTranslation.Lock to release. But I don't know that the extra complexity
+		// is worth it. Especially when it would slam the system pretty hard if lots
+		// of lookups are being performed.
+
+		stc.mibName, stc.oidNum, stc.oidText, stc.conversion, stc.node, stc.err = snmp.SnmpTranslateCall(oid)
+		gosmiSnmpTranslateCaches[oid] = stc
+	}
+
+	gosmiSnmpTranslateCachesLock.Unlock()
+
+	return stc.mibName, stc.oidNum, stc.oidText, stc.conversion, stc.node, stc.err
+}
+
+type gosmiSnmpTableCache struct {
+	mibName string
+	oidNum  string
+	oidText string
+	fields  []Field
+	err     error
+}
+
+var gosmiSnmpTableCaches map[string]gosmiSnmpTableCache
+var gosmiSnmpTableCachesLock sync.Mutex
+
+// snmpTable resolves the given OID as a table, providing information about the
+// table and fields within.
+//nolint:revive //Too many return variable but necessary
+func (g *gosmiTranslator) SnmpTable(oid string) (
+	mibName string, oidNum string, oidText string,
+	fields []Field,
+	err error) {
+	gosmiSnmpTableCachesLock.Lock()
+	if gosmiSnmpTableCaches == nil {
+		gosmiSnmpTableCaches = map[string]gosmiSnmpTableCache{}
+	}
+
+	var stc gosmiSnmpTableCache
+	var ok bool
+	if stc, ok = gosmiSnmpTableCaches[oid]; !ok {
+		stc.mibName, stc.oidNum, stc.oidText, stc.fields, stc.err = g.SnmpTableCall(oid)
+		gosmiSnmpTableCaches[oid] = stc
+	}
+
+	gosmiSnmpTableCachesLock.Unlock()
+	return stc.mibName, stc.oidNum, stc.oidText, stc.fields, stc.err
+}
+
+//nolint:revive //Too many return variable but necessary
+func (g *gosmiTranslator) SnmpTableCall(oid string) (mibName string, oidNum string, oidText string, fields []Field, err error) {
+	mibName, oidNum, oidText, _, node, err := g.SnmpTranslateFull(oid)
+	if err != nil {
+		return "", "", "", nil, fmt.Errorf("translating: %w", err)
+	}
+
+	mibPrefix := mibName + "::"
+
+	col, tagOids, err := snmp.GetIndex(oidNum, mibPrefix, node)
+
+	for _, c := range col {
+		_, isTag := tagOids[mibPrefix+c]
+		fields = append(fields, Field{Name: c, Oid: mibPrefix + c, IsTag: isTag})
+	}
+
+	return mibName, oidNum, oidText, fields, err
+}