Completely refactor snmp plugin

- use snmpget/snmpwalk terminology
- use snmptranslate to get MIBs

etc/telegraf.conf

@@ -1397,35 +1397,49 @@
 #   #priv_protocol = ""            # Values: "DES", "AES", ""
 #   #priv_password = ""
 #
-#   ## measurement name
+#   ## Each 'tag' is an "snmpget" request. Tags are inherited by snmp 'walk'
-#   name = "system"
+#   ## and 'get' requests specified below. If a name for the tag is not provided,
-#   ## SNMP fields are gotten by using an "snmpget" request. If a name is not
+#   ## we will attempt to use snmptranslate on the OID to get the MIB name.
-#   ## specified, we attempt to use snmptranslate on the OID to get the MIB name.
+#   [[inputs.snmp.tag]]
-#   [[inputs.snmp.field]]
+#     name = "sys_name" # optional, tag name
-#     name = "hostname"
+#     oid = ".1.3.6.1.2.1.1.5.0"
-#     oid = ".1.2.3.0.1.1"
+#   [[inputs.snmp.tag]]
-#   [[inputs.snmp.field]]
+#     name = "sys_location"
-#     name = "uptime"
+#     oid = ".1.3.6.1.2.1.1.6.0"
-#     oid = ".1.2.3.0.1.200"
-#   [[inputs.snmp.field]]
-#     oid = ".1.2.3.0.1.201"
 #
-#   [[inputs.snmp.table]]
+#   ## optional, name of the measurement that each 'get' field will be under.
-#     ## measurement name
+#   name = "snmp"
-#     name = "remote_servers"
+#   ## Each 'get' is an "snmpget" request. If a name for the field is not provided,
-#     inherit_tags = ["hostname"]
+#   ## we will attempt to use snmptranslate on the OID to get the MIB name.
-#     ## SNMP table fields must be specified individually. If the table field has
+#   [[inputs.snmp.get]]
-#     ## multiple rows, they will all be gotten.
+#     name = "snmp_in_packets" # optional, field name
-#     [[inputs.snmp.table.field]]
+#     oid = ".1.3.6.1.2.1.11.1.0"
-#       name = "server"
+#   [[inputs.snmp.get]]
-#       oid = ".1.2.3.0.0.0"
+#     oid = ".1.3.6.1.2.1.11.2.0"
-#       is_tag = true
+#
-#     [[inputs.snmp.table.field]]
+#   ## An SNMP walk will do an "snmpwalk" from the given root OID.
-#       name = "connections"
+#   ## Each OID it encounters will be converted into a field on the measurement.
-#       oid = ".1.2.3.0.0.1"
+#   ## We will attempt to use snmptranslate on the OID to get the MIB names for
-#     [[inputs.snmp.table.field]]
+#   ## each field.
-#       name = "latency"
+#   [[inputs.snmp.walk]]
-#       oid = ".1.2.3.0.0.2"
+#     ## optional, inherit_tags specifies which top-level tags to inherit.
+#     ## Globs are supported.
+#     inherit_tags = ["sys_*"]
+#     name = "snmp_metrics" # measurement name
+#     root_oid = ".1.3.6.1.2.1.11"
+#
+#   [[inputs.snmp.walk]]
+#     ## optional, 'include' specifies MIB names to include in the walk.
+#     ## 'exclude' is also available, although they're mutually-exclusive.
+#     ## Globs are supported.
+#     include = ["if*"]
+#     name = "ifTable"
+#     root_oid = ".1.3.6.1.2.1.2.2"
+#
+#   [[inputs.snmp.walk]]
+#     exclude = ["ifAlias"]
+#     name = "ifXTable"
+#     root_oid = ".1.3.6.1.2.1.31.1.1"
 
 
 # # DEPRECATED: This will be removed in a future release.

plugins/inputs/snmp/gosnmp.go

@@ -0,0 +1,66 @@
+package snmp
+
+import (
+	"fmt"
+
+	"github.com/soniah/gosnmp"
+)
+
+// 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 fmt.Errorf("reconnecting %s", err)
+		}
+	}
+	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, fmt.Errorf("reconnecting %s", err)
+		}
+	}
+	return nil, err
+}

plugins/inputs/snmp/snmp.go

@@ -2,7 +2,6 @@ package snmp
 
 import (
 	"fmt"
-	"math"
 	"net"
 	"os/exec"
 	"strconv"
@@ -10,6 +9,7 @@ import (
 	"time"
 
 	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/filter"
 	"github.com/influxdata/telegraf/internal"
 	"github.com/influxdata/telegraf/plugins/inputs"
 
@@ -36,35 +36,48 @@ const sampleConfig = `
   #priv_protocol = ""            # Values: "DES", "AES", ""
   #priv_password = ""
 
-  ## measurement name
+  ## Each 'tag' is an "snmpget" request. Tags are inherited by snmp 'walk'
-  name = "system"
+  ## and 'get' requests specified below. If a name for the tag is not provided,
-  ## SNMP fields are gotten by using an "snmpget" request. If a name is not
+  ## we will attempt to get the MIB name.
-  ## specified, we attempt to use snmptranslate on the OID to get the MIB name.
+  [[inputs.snmp.tag]]
-  [[inputs.snmp.field]]
+    name = "sys_name" # optional, tag name
-    name = "hostname"
+    oid = ".1.3.6.1.2.1.1.5.0"
-    oid = ".1.2.3.0.1.1"
+  [[inputs.snmp.tag]]
-  [[inputs.snmp.field]]
+    name = "sys_location"
-    name = "uptime"
+    oid = ".1.3.6.1.2.1.1.6.0"
-    oid = ".1.2.3.0.1.200"
-  [[inputs.snmp.field]]
-    oid = ".1.2.3.0.1.201"
 
-  [[inputs.snmp.table]]
+  ## optional, name of the measurement that each 'get' field will be under.
-    ## measurement name
+  name = "snmp"
-    name = "remote_servers"
+  ## Each 'get' is an "snmpget" request. If a name for the field is not provided,
-    inherit_tags = ["hostname"]
+  ## we will attempt to get the MIB name.
-    ## SNMP table fields must be specified individually. If the table field has
+  [[inputs.snmp.get]]
-    ## multiple rows, they will all be gotten.
+    name = "snmp_in_packets" # optional, field name
-    [[inputs.snmp.table.field]]
+    oid = ".1.3.6.1.2.1.11.1.0"
-      name = "server"
+  [[inputs.snmp.get]]
-      oid = ".1.2.3.0.0.0"
+    oid = ".1.3.6.1.2.1.11.2.0"
-      is_tag = true
+
-    [[inputs.snmp.table.field]]
+  ## An SNMP walk will do an "snmpwalk" from the given root OID.
-      name = "connections"
+  ## Each OID it encounters will be converted into a field on the measurement.
-      oid = ".1.2.3.0.0.1"
+  ## We will attempt to get the MIB names for each field.
-    [[inputs.snmp.table.field]]
+  [[inputs.snmp.walk]]
-      name = "latency"
+    ## optional, inherit_tags specifies which top-level tags to inherit.
-      oid = ".1.2.3.0.0.2"
+    ## Globs are supported.
+    inherit_tags = ["sys_*"]
+    name = "snmp_metrics" # measurement name
+    root_oid = ".1.3.6.1.2.1.11"
+
+  [[inputs.snmp.walk]]
+    ## optional, 'include' specifies MIB names to include in the walk.
+    ## 'exclude' is also available, although they're mutually-exclusive.
+    ## Globs are supported.
+    include = ["if*"]
+    name = "ifTable"
+    root_oid = ".1.3.6.1.2.1.2.2"
+
+  [[inputs.snmp.walk]]
+    exclude = ["ifAlias"]
+    name = "ifXTable"
+    root_oid = ".1.3.6.1.2.1.31.1.1"
 `
 
 // Snmp holds the configuration for the plugin.
@@ -94,106 +107,59 @@ type Snmp struct {
 	// 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
+	// Telegraf chokes if we try to embed a Table. So instead we have to embed
-	// fields of a Table, and construct a Table during runtime.
+	// the fields of a Table, and construct a Table during runtime.
 	Name  string
-	Fields []Field `toml:"field"`
+	Gets  []Get  `toml:"get"`
+	Walks []Walk `toml:"walk"`
+	Tags  []Tag  `toml:"tag"`
+
+	// oidToMib is a map of OIDs to MIBs.
+	oidToMib map[string]string
+	// translateBin is the location of the 'snmptranslate' binary.
+	translateBin string
 
 	connectionCache map[string]snmpConnection
-
-	inited bool
 }
 
-// Table holds the configuration for a SNMP table.
+// Get holds the configuration for a Get to look up.
-type Table struct {
+type Get 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.
+	Oid string
+}
+
+// Walker holds the configuration for a Walker to look up.
+type Walk struct {
+	// Name will be the name of the measurement.
+	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
+	RootOid string
-	// IsTag controls whether this OID is output as a tag or a value.
+	// Include is a list of glob filters, only OID/MIBs that match these will
-	IsTag bool
+	// be included in the resulting output metrics.
-	// Conversion controls any type conversion that is done on the value.
+	Include []string
-	//  "float"/"float(0)" will convert the value into a float.
+	include filter.Filter
-	//  "float(X)" will convert the value into a float, and then move the decimal before Xth right-most digit.
+	// Exclude is the exact opposite of Include
-	//  "int" will conver the value into an integer.
+	Exclude []string
-	Conversion string
+	exclude filter.Filter
+	// InheritTags is a list of tags to inherit from the top-level snmp.tag
+	// configuration.
+	InheritTags []string
+	inheritTags filter.Filter
 }
 
-// RTable is the resulting table built from a Table.
+// Tag holds the config for a tag.
-type RTable struct {
+type Tag struct {
-	// Name is the name of the field, copied from Table.Name.
+	// Name will be the name of the tag.
 	Name string
-	// Time is the time the table was built.
+	// OID is prefix for this field.
-	Time time.Time
+	Oid string
-	// 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...),
-	}
 }
 
 // SampleConfig returns the default configuration of the input.
@@ -210,258 +176,150 @@ func (s *Snmp) Description() string {
 // 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 {
-	if !s.inited {
-		s.initOidNames()
-	}
-	s.inited = true
-	var errs Errors
 	for _, agent := range s.Agents {
 		gs, err := s.getConnection(agent)
 		if err != nil {
-			errs = append(errs, Errorf(err, "agent %s", agent))
+			acc.AddError(fmt.Errorf("Agent %s, err: %s", agent, err))
 			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 {
+		// Gather all snmp tags
-			errs = append(errs, Errorf(err, "agent %s", agent))
+		for _, t := range s.Tags {
-		}
+			tagval, err := get(gs, t.Oid)
-
-		// 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
-}
-
-// initOidNames loops through each [[inputs.snmp.field]] defined.
-// If the field doesn't have a 'name' defined, it will attempt to use
-// snmptranslate to get a name for the OID. If snmptranslate doesn't return a
-// name, or snmptranslate is not available, then use the OID as the name.
-func (s *Snmp) initOidNames() {
-	bin, _ := exec.LookPath("snmptranslate")
-
-	// Lookup names for each OID defined as a "field"
-	for i, field := range s.Fields {
-		if field.Name != "" {
-			continue
-		}
-		s.Fields[i].Name = lookupOidName(bin, field.Oid)
-	}
-
-	// Lookup names for each OID defined as a "table.field"
-	for i, table := range s.Tables {
-		for j, field := range table.Fields {
-			if field.Name != "" {
-				continue
-			}
-			s.Tables[i].Fields[j].Name = lookupOidName(bin, field.Oid)
-		}
-	}
-}
-
-func lookupOidName(bin, oid string) string {
-	name := oid
-	if bin != "" {
-		out, err := internal.CombinedOutputTimeout(
-			exec.Command(bin, "-Os", oid),
-			time.Millisecond*250)
-		if err == nil && len(out) > 0 {
-			name = strings.TrimSpace(string(out))
-		}
-	}
-	return name
-}
-
-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
+				acc.AddError(fmt.Errorf("Agent %s, err: %s", agent, err))
+				continue
+			}
+			if tagval == nil {
+				continue
+			}
+			name := t.Name
+			if name == "" {
+				name, _ = s.getMibName(t.Oid)
+			}
+			if s, ok := tagval.(string); ok {
+				topTags[name] = s
+			}
 		}
 
-	for _, tr := range rt.Rows {
+		// Gather all snmp gets
-		if !walk {
+		fields := map[string]interface{}{}
-			// top-level table. Add tags to topTags.
+		for _, g := range s.Gets {
-			for k, v := range tr.Tags {
+			val, err := get(gs, g.Oid)
-				topTags[k] = v
+			if err != nil {
+				acc.AddError(fmt.Errorf("Agent %s, err: %s", agent, err))
+				continue
 			}
-		} else {
+			if val == nil {
-			// real table. Inherit any specified tags.
+				continue
-			for _, k := range t.InheritTags {
+			}
-				if v, ok := topTags[k]; ok {
+			name := g.Name
-					tr.Tags[k] = v
+			if name == "" {
+				name, _ = s.getMibName(g.Oid)
+			}
+			fields[name] = val
+		}
+		if len(fields) > 0 {
+			acc.AddFields(s.Name, fields, topTags, time.Now())
+		}
+
+		// Gather all snmp walks
+		for _, w := range s.Walks {
+			w.compileWalkFilters(acc)
+			allfields := map[string]map[string]interface{}{}
+			now := time.Now()
+			s.walk(gs, allfields, w.RootOid, w.include, w.exclude)
+			for index, wfields := range allfields {
+				tags := copyTags(topTags, w.inheritTags)
+				tags["index"] = index
+				acc.AddFields(w.Name, wfields, tags, now)
 			}
 		}
 	}
-		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.
+// walk does a walk and populates the given 'fields' map with whatever it finds.
-func (t Table) Build(gs snmpConnection, walk bool) (*RTable, error) {
+// as it goes, it attempts to lookup the MIB name of each OID it encounters.
-	rows := map[string]RTableRow{}
+func (s *Snmp) walk(
-
+	gs snmpConnection,
-	tagCount := 0
+	fields map[string]map[string]interface{},
-	for _, f := range t.Fields {
+	rootOid string,
-		if f.IsTag {
+	include filter.Filter,
-			tagCount++
+	exclude filter.Filter,
+) {
+	gs.Walk(rootOid, func(ent gosnmp.SnmpPDU) error {
+		name, index := s.getMibName(ent.Name)
+		if include != nil {
+			if !include.Match(name) {
+				return nil
 			}
-
+		} else if exclude != nil {
-		if len(f.Oid) == 0 {
+			if exclude.Match(name) {
-			return nil, fmt.Errorf("cannot have empty OID")
+				return nil
 			}
-		var oid string
+		}
-		if f.Oid[0] == '.' {
+		if _, ok := fields[index]; ok {
-			oid = f.Oid
+			fields[index][name] = normalize(ent.Value)
 		} else {
-			// make sure OID has "." because the BulkWalkAll results do, and the prefix needs to match
+			fields[index] = map[string]interface{}{
-			oid = "." + f.Oid
+				name: normalize(ent.Value),
 			}
-
-		// 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
 	})
+}
+
+// get simply gets the given OID and converts it to the given type.
+func get(gs snmpConnection, oid string) (interface{}, error) {
+	pkt, err := gs.Get([]string{oid})
 	if err != nil {
-				if _, ok := err.(NestedError); !ok {
+		return nil, fmt.Errorf("Error performing get: %s", err)
-					return nil, Errorf(err, "performing bulk walk")
-				}
 	}
+	if pkt != nil && len(pkt.Variables) > 0 && pkt.Variables[0].Type != gosnmp.NoSuchObject {
+		ent := pkt.Variables[0]
+		return normalize(ent.Value), nil
 	}
+	return nil, nil
+}
 
-		for i, v := range ifv {
+func (s *Snmp) getMibName(oid string) (string, string) {
-			rtr, ok := rows[i]
+	name, ok := s.oidToMib[oid]
 	if !ok {
-				rtr = RTableRow{}
+		// lookup the mib using snmptranslate
-				rtr.Tags = map[string]string{}
+		name = lookupOidName(s.translateBin, oid)
-				rtr.Fields = map[string]interface{}{}
+		s.oidToMib[oid] = name
-				rows[i] = rtr
 	}
-			if f.IsTag {
+	return separateIndex(name)
-				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.
+func (w *Walk) compileWalkFilters(acc telegraf.Accumulator) {
-// We interact through an interface so we can mock it out in tests.
+	// if it's the first gather, compile any inherit_tags filter:
-type snmpConnection interface {
+	if len(w.InheritTags) > 0 && w.inheritTags == nil {
-	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.
+		w.inheritTags, err = filter.CompileFilter(w.InheritTags)
-	// Unfortunately we can't distinguish between an error returned by gosnmp, and one returned by the walk function.
+		if err != nil {
-	for i := 0; i < 2; i++ {
+			acc.AddError(err)
-		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
+	// if it's the first gather, compile any include filter:
-}
+	if len(w.Include) > 0 && w.include == nil {
-
-// 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
+		w.include, err = filter.CompileFilter(w.Include)
-	for i := 0; i < 2; i++ {
+		if err != nil {
-		pkt, err = gsw.GoSNMP.Get(oids)
+			acc.AddError(err)
-		if err == nil {
+		}
-			return pkt, nil
+	}
-		}
+	// if it's the first gather, compile any exclude filter:
-		if err := gsw.GoSNMP.Connect(); err != nil {
+	if len(w.Exclude) > 0 && w.exclude == nil {
-			return nil, Errorf(err, "reconnecting")
+		var err error
+		w.exclude, err = filter.CompileFilter(w.Exclude)
+		if err != nil {
+			acc.AddError(err)
 		}
 	}
-	return nil, err
 }
 
 // getConnection creates a snmpConnection (*gosnmp.GoSNMP) object and caches the
@@ -479,7 +337,7 @@ func (s *Snmp) getConnection(agent string) (snmpConnection, error) {
 	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")
+			return nil, fmt.Errorf("reconnecting %s", err)
 		}
 		host = agent
 		portStr = "161"
@@ -488,13 +346,13 @@ func (s *Snmp) getConnection(agent string) (snmpConnection, error) {
 
 	port, err := strconv.ParseUint(portStr, 10, 16)
 	if err != nil {
-		return nil, Errorf(err, "parsing port")
+		return nil, fmt.Errorf("reconnecting %s", err)
 	}
 	gs.Port = uint16(port)
 
 	if s.Timeout != "" {
 		if gs.Timeout, err = time.ParseDuration(s.Timeout); err != nil {
-			return nil, Errorf(err, "parsing timeout")
+			return nil, fmt.Errorf("reconnecting %s", err)
 		}
 	} else {
 		gs.Timeout = time.Second * 1
@@ -568,112 +426,77 @@ func (s *Snmp) getConnection(agent string) (snmpConnection, error) {
 		}
 
 		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")
+		return nil, fmt.Errorf("setting up connection %s", err)
 	}
 
 	s.connectionCache[agent] = gs
 	return gs, nil
 }
 
-// fieldConvert converts from any type according to the conv specification
+// normalize normalizes the given interface for metric storage.
-//  "float"/"float(0)" will convert the value into a float.
+func normalize(v interface{}) interface{} {
-//  "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 = string(vt)
-			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
 }
 
+func copyTags(in map[string]string, inheritTags filter.Filter) map[string]string {
+	out := map[string]string{}
+	for k, v := range in {
+		if inheritTags != nil {
+			if !inheritTags.Match(k) {
+				continue
+			}
+		}
+		out[k] = v
+	}
+	return out
+}
+
+// lookupOidName looks up the MIB name of the given OID using the provided
+// snmptranslate binary. If a name is not found, then we just return the OID.
+func lookupOidName(bin, oid string) string {
+	name := oid
+	if bin != "" {
+		out, err := internal.CombinedOutputTimeout(
+			exec.Command(bin, "-Os", oid),
+			time.Millisecond*250)
+		if err == nil && len(out) > 0 {
+			name = strings.TrimSpace(string(out))
+		}
+	}
+	return name
+}
+
+// separateIndex takes an input string (either a MIB or an OID) and separates
+// out the index from it, ie:
+//   ifName.1     -> (ifName, 1)
+//   snmpInPkts.0 -> (snmpInPkts, 0)
+//   .1.3.6.4.2.0 -> (.1.3.6.4.2, 0)
+func separateIndex(in string) (string, string) {
+	items := strings.Split(in, ".")
+	if len(items) == 1 {
+		return in, "0"
+	}
+	index := items[len(items)-1]
+	return strings.Join(items[0:len(items)-1], "."), index
+}
+
 func init() {
+	bin, _ := exec.LookPath("snmptranslate")
 	inputs.Add("snmp", func() telegraf.Input {
 		return &Snmp{
+			Name:           "snmp",
 			Retries:        5,
 			MaxRepetitions: 50,
+			translateBin:   bin,
+			oidToMib:       make(map[string]string),
 		}
 	})
 }