snmp: make snmptranslate not required (influxdata#2008)

CHANGELOG.md

@@ -21,6 +21,12 @@
 - [#1949](https://github.com/influxdata/telegraf/issues/1949): Fix windows `net` plugin.
 - [#1775](https://github.com/influxdata/telegraf/issues/1775): Cache & expire metrics for delivery to prometheus
 
+## v1.1.2 [2016-12-12]
+
+### Bugfixes
+
+- [#2007](https://github.com/influxdata/telegraf/issues/2007): Make snmptranslate not required when using numeric OID.
+
 ## v1.1.1 [2016-11-14]
 
 ### Bugfixes

plugins/inputs/snmp/snmp.go

@@ -848,6 +848,11 @@ func snmpTranslate(oid string) (mibName string, oidNum string, oidText string, c
 		out, err = execCmd("snmptranslate", "-Td", "-Ob", oid)
 	} else {
 		out, err = execCmd("snmptranslate", "-Td", "-Ob", "-m", "all", oid)
+		if err, ok := err.(*exec.Error); ok && err.Err == exec.ErrNotFound {
+			// Silently discard error if snmptranslate not found and we have a numeric OID.
+			// Meaning we can get by without the lookup.
+			return "", oid, oid, "", nil
+		}
 	}
 	if err != nil {
 		return "", "", "", "", err

plugins/inputs/snmp/snmp_test.go

@@ -4,6 +4,7 @@ package snmp
 import (
 	"fmt"
 	"net"
+	"os/exec"
 	"sync"
 	"testing"
 	"time"
@@ -198,6 +199,56 @@ func TestSnmpInit(t *testing.T) {
 	}, s.Fields[0])
 }
 
+func TestSnmpInit_noTranslate(t *testing.T) {
+	// override execCommand so it returns exec.ErrNotFound
+	defer func(ec func(string, ...string) *exec.Cmd) { execCommand = ec }(execCommand)
+	execCommand = func(_ string, _ ...string) *exec.Cmd {
+		return exec.Command("snmptranslateExecErrNotFound")
+	}
+
+	s := &Snmp{
+		Fields: []Field{
+			{Oid: ".1.1.1.1", Name: "one", IsTag: true},
+			{Oid: ".1.1.1.2", Name: "two"},
+			{Oid: ".1.1.1.3"},
+		},
+		Tables: []Table{
+			{Fields: []Field{
+				{Oid: ".1.1.1.4", Name: "four", IsTag: true},
+				{Oid: ".1.1.1.5", Name: "five"},
+				{Oid: ".1.1.1.6"},
+			}},
+		},
+	}
+
+	err := s.init()
+	require.NoError(t, err)
+
+	assert.Equal(t, ".1.1.1.1", s.Fields[0].Oid)
+	assert.Equal(t, "one", s.Fields[0].Name)
+	assert.Equal(t, true, s.Fields[0].IsTag)
+
+	assert.Equal(t, ".1.1.1.2", s.Fields[1].Oid)
+	assert.Equal(t, "two", s.Fields[1].Name)
+	assert.Equal(t, false, s.Fields[1].IsTag)
+
+	assert.Equal(t, ".1.1.1.3", s.Fields[2].Oid)
+	assert.Equal(t, ".1.1.1.3", s.Fields[2].Name)
+	assert.Equal(t, false, s.Fields[2].IsTag)
+
+	assert.Equal(t, ".1.1.1.4", s.Tables[0].Fields[0].Oid)
+	assert.Equal(t, "four", s.Tables[0].Fields[0].Name)
+	assert.Equal(t, true, s.Tables[0].Fields[0].IsTag)
+
+	assert.Equal(t, ".1.1.1.5", s.Tables[0].Fields[1].Oid)
+	assert.Equal(t, "five", s.Tables[0].Fields[1].Name)
+	assert.Equal(t, false, s.Tables[0].Fields[1].IsTag)
+
+	assert.Equal(t, ".1.1.1.6", s.Tables[0].Fields[2].Oid)
+	assert.Equal(t, ".1.1.1.6", s.Tables[0].Fields[2].Name)
+	assert.Equal(t, false, s.Tables[0].Fields[2].IsTag)
+}
+
 func TestGetSNMPConnection_v2(t *testing.T) {
 	s := &Snmp{
 		Timeout:   internal.Duration{Duration: 3 * time.Second},