Support NX-OS telemetry extensions in cisco_telemetry_mdt (#6177)

Gopkg.lock

@@ -1486,6 +1486,7 @@
     "credentials",
     "credentials/oauth",
     "encoding",
+    "encoding/gzip",
     "encoding/proto",
     "grpclog",
     "internal",
@@ -1813,6 +1814,7 @@
     "google.golang.org/grpc",
     "google.golang.org/grpc/codes",
     "google.golang.org/grpc/credentials",
+    "google.golang.org/grpc/encoding/gzip",
     "google.golang.org/grpc/metadata",
     "google.golang.org/grpc/peer",
     "google.golang.org/grpc/status",

plugins/inputs/cisco_telemetry_mdt/README.md

@@ -29,6 +29,9 @@ The TCP dialout transport is supported on IOS XR (32-bit and 64-bit) 6.1.x and l
  ##  transport only.
  # tls_allowed_cacerts = ["/etc/telegraf/clientca.pem"]
 
+ ## Define (for certain nested telemetry measurements with embedded tags) which fields are tags
+ # embedded_tags = ["Cisco-IOS-XR-qos-ma-oper:qos/interface-table/interface/input/service-policy-names/service-policy-instance/statistics/class-stats/class-name"]
+
  ## Define aliases to map telemetry encoding paths to simple measurement names
  [inputs.cisco_telemetry_mdt.aliases]
    ifstats = "ietf-interfaces:interfaces-state/interface/statistics"

plugins/inputs/cisco_telemetry_mdt/cisco_telemetry_mdt.go

@@ -7,10 +7,14 @@ import (
 	"io"
 	"log"
 	"net"
+	"path"
+	"strconv"
 	"strings"
 	"sync"
 	"time"
 
+	"github.com/influxdata/telegraf/metric"
+
 	dialout "github.com/cisco-ie/nx-telemetry-proto/mdt_dialout"
 	telemetry "github.com/cisco-ie/nx-telemetry-proto/telemetry_bis"
 	"github.com/golang/protobuf/proto"
@@ -19,6 +23,9 @@ import (
 	"github.com/influxdata/telegraf/plugins/inputs"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials"
+
+	// Register GRPC gzip decoder to support compressed telemetry
+	_ "google.golang.org/grpc/encoding/gzip"
 	"google.golang.org/grpc/peer"
 )
 
@@ -34,6 +41,7 @@ type CiscoTelemetryMDT struct {
 	ServiceAddress string            `toml:"service_address"`
 	MaxMsgSize     int               `toml:"max_msg_size"`
 	Aliases        map[string]string `toml:"aliases"`
+	EmbeddedTags   []string          `toml:"embedded_tags"`
 
 	// GRPC TLS settings
 	internaltls.ServerConfig
@@ -43,9 +51,12 @@ type CiscoTelemetryMDT struct {
 	listener   net.Listener
 
 	// Internal state
-	aliases map[string]string
+	aliases   map[string]string
-	acc     telegraf.Accumulator
+	warned    map[string]struct{}
-	wg      sync.WaitGroup
+	extraTags map[string]map[string]struct{}
+	mutex     sync.Mutex
+	acc       telegraf.Accumulator
+	wg        sync.WaitGroup
 }
 
 // Start the Cisco MDT service
@@ -58,11 +69,22 @@ func (c *CiscoTelemetryMDT) Start(acc telegraf.Accumulator) error {
 	}
 
 	// Invert aliases list
+	c.warned = make(map[string]struct{})
 	c.aliases = make(map[string]string, len(c.Aliases))
 	for alias, path := range c.Aliases {
 		c.aliases[path] = alias
 	}
 
+	// Fill extra tags
+	c.extraTags = make(map[string]map[string]struct{})
+	for _, tag := range c.EmbeddedTags {
+		dir := path.Dir(tag)
+		if _, hasKey := c.extraTags[dir]; !hasKey {
+			c.extraTags[dir] = make(map[string]struct{})
+		}
+		c.extraTags[dir][path.Base(tag)] = struct{}{}
+	}
+
 	switch c.Transport {
 	case "tcp":
 		// TCP dialout server accept routine
@@ -76,6 +98,7 @@ func (c *CiscoTelemetryMDT) Start(acc telegraf.Accumulator) error {
 		var opts []grpc.ServerOption
 		tlsConfig, err := c.ServerConfig.TLSConfig()
 		if err != nil {
+			c.listener.Close()
 			return err
 		} else if tlsConfig != nil {
 			opts = append(opts, grpc.Creds(credentials.NewTLS(tlsConfig)))
@@ -198,6 +221,8 @@ func (c *CiscoTelemetryMDT) MdtDialout(stream dialout.GRPCMdtDialout_MdtDialoutS
 		log.Printf("D! [inputs.cisco_telemetry_mdt]: Accepted Cisco MDT GRPC dialout connection from %s", peer.Addr)
 	}
 
+	var chunkBuffer bytes.Buffer
+
 	for {
 		packet, err := stream.Recv()
 		if err != nil {
@@ -212,7 +237,18 @@ func (c *CiscoTelemetryMDT) MdtDialout(stream dialout.GRPCMdtDialout_MdtDialoutS
 			break
 		}
 
-		c.handleTelemetry(packet.Data)
+		// Reassemble chunked telemetry data received from NX-OS
+		if packet.TotalSize == 0 {
+			c.handleTelemetry(packet.Data)
+		} else if int(packet.TotalSize) <= c.MaxMsgSize {
+			chunkBuffer.Write(packet.Data)
+			if chunkBuffer.Len() >= int(packet.TotalSize) {
+				c.handleTelemetry(chunkBuffer.Bytes())
+				chunkBuffer.Reset()
+			}
+		} else {
+			c.acc.AddError(fmt.Errorf("dropped too large packet: %dB > %dB", packet.TotalSize, c.MaxMsgSize))
+		}
 	}
 
 	if peerOK {
@@ -224,115 +260,239 @@ func (c *CiscoTelemetryMDT) MdtDialout(stream dialout.GRPCMdtDialout_MdtDialoutS
 
 // Handle telemetry packet from any transport, decode and add as measurement
 func (c *CiscoTelemetryMDT) handleTelemetry(data []byte) {
-	var namebuf bytes.Buffer
+	msg := &telemetry.Telemetry{}
-	telemetry := &telemetry.Telemetry{}
+	err := proto.Unmarshal(data, msg)
-	err := proto.Unmarshal(data, telemetry)
 	if err != nil {
 		c.acc.AddError(fmt.Errorf("Cisco MDT failed to decode: %v", err))
 		return
 	}
 
-	for _, gpbkv := range telemetry.DataGpbkv {
+	grouper := metric.NewSeriesGrouper()
-		var fields map[string]interface{}
+	for _, gpbkv := range msg.DataGpbkv {
-
 		// Produce metadata tags
 		var tags map[string]string
 
 		// Top-level field may have measurement timestamp, if not use message timestamp
 		measured := gpbkv.Timestamp
 		if measured == 0 {
-			measured = telemetry.MsgTimestamp
+			measured = msg.MsgTimestamp
 		}
 
 		timestamp := time.Unix(int64(measured/1000), int64(measured%1000)*1000000)
 
-		// Populate tags and fields from toplevel GPBKV fields "keys" and "content"
+		// Find toplevel GPBKV fields "keys" and "content"
+		var keys, content *telemetry.TelemetryField = nil, nil
 		for _, field := range gpbkv.Fields {
-			switch field.Name {
+			if field.Name == "keys" {
-			case "keys":
+				keys = field
-				tags = make(map[string]string, len(field.Fields)+2)
+			} else if field.Name == "content" {
-				tags["source"] = telemetry.GetNodeIdStr()
+				content = field
-				tags["subscription"] = telemetry.GetSubscriptionIdStr()
-				for _, subfield := range field.Fields {
-					c.parseGPBKVField(subfield, &namebuf, telemetry.EncodingPath, timestamp, tags, nil)
-				}
-			case "content":
-				fields = make(map[string]interface{}, len(field.Fields))
-				for _, subfield := range field.Fields {
-					c.parseGPBKVField(subfield, &namebuf, telemetry.EncodingPath, timestamp, tags, fields)
-				}
-			default:
-				log.Printf("I! [inputs.cisco_telemetry_mdt]: Unexpected top-level MDT field: %s", field.Name)
 			}
 		}
 
-		// Find best alias for encoding path and emit measurement
+		if keys == nil || content == nil {
-		if len(fields) > 0 && len(tags) > 0 && len(telemetry.EncodingPath) > 0 {
+			log.Printf("I! [inputs.cisco_telemetry_mdt]: Message from %s missing keys or content", msg.GetNodeIdStr())
-			name := telemetry.EncodingPath
+			continue
-			if alias, ok := c.aliases[name]; ok {
-				tags["path"] = name
-				name = alias
-			} else {
-				log.Printf("D! [inputs.cisco_telemetry_mdt]: No measurement alias for encoding path: %s", name)
-			}
-			c.acc.AddFields(name, fields, tags, timestamp)
-		} else {
-			c.acc.AddError(fmt.Errorf("empty encoding path or measurement"))
 		}
+
+		// Parse keys
+		tags = make(map[string]string, len(keys.Fields)+3)
+		tags["source"] = msg.GetNodeIdStr()
+		tags["subscription"] = msg.GetSubscriptionIdStr()
+		tags["path"] = msg.GetEncodingPath()
+
+		for _, subfield := range keys.Fields {
+			c.parseKeyField(tags, subfield, "")
+		}
+
+		// Parse values
+		for _, subfield := range content.Fields {
+			c.parseContentField(grouper, subfield, "", msg.EncodingPath, tags, timestamp)
+		}
+	}
+
+	for _, metric := range grouper.Metrics() {
+		c.acc.AddMetric(metric)
 	}
 }
 
-// Recursively parse GPBKV field structure into fields or tags
+func decodeValue(field *telemetry.TelemetryField) interface{} {
-func (c *CiscoTelemetryMDT) parseGPBKVField(field *telemetry.TelemetryField, namebuf *bytes.Buffer,
-	path string, timestamp time.Time, tags map[string]string, fields map[string]interface{}) {
-
-	namelen := namebuf.Len()
-	if namelen > 0 {
-		namebuf.WriteRune('/')
-	}
-	namebuf.WriteString(strings.Replace(field.Name, "-", "_", -1))
-
-	// Decode Telemetry field value if set
-	var value interface{}
 	switch val := field.ValueByType.(type) {
 	case *telemetry.TelemetryField_BytesValue:
-		value = val.BytesValue
+		return val.BytesValue
 	case *telemetry.TelemetryField_StringValue:
-		value = val.StringValue
+		if len(val.StringValue) > 0 {
+			return val.StringValue
+		}
 	case *telemetry.TelemetryField_BoolValue:
-		value = val.BoolValue
+		return val.BoolValue
 	case *telemetry.TelemetryField_Uint32Value:
-		value = val.Uint32Value
+		return val.Uint32Value
 	case *telemetry.TelemetryField_Uint64Value:
-		value = val.Uint64Value
+		return val.Uint64Value
 	case *telemetry.TelemetryField_Sint32Value:
-		value = val.Sint32Value
+		return val.Sint32Value
 	case *telemetry.TelemetryField_Sint64Value:
-		value = val.Sint64Value
+		return val.Sint64Value
 	case *telemetry.TelemetryField_DoubleValue:
-		value = val.DoubleValue
+		return val.DoubleValue
 	case *telemetry.TelemetryField_FloatValue:
-		value = val.FloatValue
+		return val.FloatValue
+	}
+	return nil
+}
+
+func decodeTag(field *telemetry.TelemetryField) string {
+	switch val := field.ValueByType.(type) {
+	case *telemetry.TelemetryField_BytesValue:
+		return string(val.BytesValue)
+	case *telemetry.TelemetryField_StringValue:
+		return val.StringValue
+	case *telemetry.TelemetryField_BoolValue:
+		if val.BoolValue {
+			return "true"
+		}
+		return "false"
+	case *telemetry.TelemetryField_Uint32Value:
+		return strconv.FormatUint(uint64(val.Uint32Value), 10)
+	case *telemetry.TelemetryField_Uint64Value:
+		return strconv.FormatUint(val.Uint64Value, 10)
+	case *telemetry.TelemetryField_Sint32Value:
+		return strconv.FormatInt(int64(val.Sint32Value), 10)
+	case *telemetry.TelemetryField_Sint64Value:
+		return strconv.FormatInt(val.Sint64Value, 10)
+	case *telemetry.TelemetryField_DoubleValue:
+		return strconv.FormatFloat(val.DoubleValue, 'f', -1, 64)
+	case *telemetry.TelemetryField_FloatValue:
+		return strconv.FormatFloat(float64(val.FloatValue), 'f', -1, 32)
+	default:
+		return ""
+	}
+}
+
+// Recursively parse tag fields
+func (c *CiscoTelemetryMDT) parseKeyField(tags map[string]string, field *telemetry.TelemetryField, prefix string) {
+	localname := strings.Replace(field.Name, "-", "_", -1)
+	name := localname
+	if len(localname) == 0 {
+		name = prefix
+	} else if len(prefix) > 0 {
+		name = prefix + "/" + localname
 	}
 
-	if value != nil {
+	if tag := decodeTag(field); len(name) > 0 && len(tag) > 0 {
-		// Distinguish between tags (keys) and fields (data) to write to
+		if _, exists := tags[localname]; !exists { // Use short keys whenever possible
-		if fields != nil {
+			tags[localname] = tag
-			fields[namebuf.String()] = value
 		} else {
-			if _, exists := tags[field.Name]; !exists { // Use short keys whenever possible
+			tags[name] = tag
-				tags[field.Name] = fmt.Sprint(value)
-			} else {
-				tags[namebuf.String()] = fmt.Sprint(value)
-			}
 		}
 	}
 
 	for _, subfield := range field.Fields {
-		c.parseGPBKVField(subfield, namebuf, path, timestamp, tags, fields)
+		c.parseKeyField(tags, subfield, name)
+	}
+}
+
+func (c *CiscoTelemetryMDT) parseContentField(grouper *metric.SeriesGrouper, field *telemetry.TelemetryField, prefix string,
+	path string, tags map[string]string, timestamp time.Time) {
+	name := strings.Replace(field.Name, "-", "_", -1)
+	if len(name) == 0 {
+		name = prefix
+	} else if len(prefix) > 0 {
+		name = prefix + "/" + name
 	}
 
-	namebuf.Truncate(namelen)
+	extraTags := c.extraTags[path+"/"+name]
+
+	if value := decodeValue(field); value != nil {
+		// Do alias lookup, to shorten measurement names
+		measurement := path
+		if alias, ok := c.aliases[path]; ok {
+			measurement = alias
+		} else {
+			c.mutex.Lock()
+			if _, haveWarned := c.warned[path]; !haveWarned {
+				log.Printf("D! [inputs.cisco_telemetry_mdt]: No measurement alias for encoding path: %s", path)
+				c.warned[path] = struct{}{}
+			}
+			c.mutex.Unlock()
+		}
+
+		grouper.Add(measurement, tags, timestamp, name, value)
+		return
+	}
+
+	if len(extraTags) > 0 {
+		for _, subfield := range field.Fields {
+			if _, isExtraTag := extraTags[subfield.Name]; isExtraTag {
+				tags[name+"/"+subfield.Name] = decodeTag(subfield)
+			}
+		}
+	}
+
+	var nxAttributes, nxChildren, nxRows *telemetry.TelemetryField
+	isNXOS := !strings.ContainsRune(path, ':') // IOS-XR and IOS-XE have a colon in their encoding path, NX-OS does not
+	for _, subfield := range field.Fields {
+		if isNXOS && subfield.Name == "attributes" && len(subfield.Fields) > 0 {
+			nxAttributes = subfield.Fields[0]
+		} else if isNXOS && subfield.Name == "children" && len(subfield.Fields) > 0 {
+			nxChildren = subfield
+		} else if isNXOS && strings.HasPrefix(subfield.Name, "ROW_") {
+			nxRows = subfield
+		} else if _, isExtraTag := extraTags[subfield.Name]; !isExtraTag { // Regular telemetry decoding
+			c.parseContentField(grouper, subfield, name, path, tags, timestamp)
+		}
+	}
+
+	if nxAttributes == nil && nxRows == nil {
+		return
+	} else if nxRows != nil {
+		// NXAPI structure: https://developer.cisco.com/docs/cisco-nexus-9000-series-nx-api-cli-reference-release-9-2x/
+		for _, row := range nxRows.Fields {
+			for i, subfield := range row.Fields {
+				if i == 0 { // First subfield contains the index, promote it from value to tag
+					tags[prefix] = decodeTag(subfield)
+				} else {
+					c.parseContentField(grouper, subfield, "", path, tags, timestamp)
+				}
+			}
+			delete(tags, prefix)
+		}
+		return
+	}
+
+	// DME structure: https://developer.cisco.com/site/nxapi-dme-model-reference-api/
+	rn := ""
+	dn := false
+
+	for _, subfield := range nxAttributes.Fields {
+		if subfield.Name == "rn" {
+			rn = decodeTag(subfield)
+		} else if subfield.Name == "dn" {
+			dn = true
+		}
+	}
+
+	if len(rn) > 0 {
+		tags[prefix] = rn
+	} else if !dn { // Check for distinguished name being present
+		c.acc.AddError(fmt.Errorf("NX-OS decoding failed: missing dn field"))
+		return
+	}
+
+	for _, subfield := range nxAttributes.Fields {
+		if subfield.Name != "rn" {
+			c.parseContentField(grouper, subfield, "", path, tags, timestamp)
+		}
+	}
+
+	if nxChildren != nil {
+		// This is a nested structure, children will inherit relative name keys of parent
+		for _, subfield := range nxChildren.Fields {
+			c.parseContentField(grouper, subfield, prefix, path, tags, timestamp)
+		}
+	}
+	delete(tags, prefix)
 }
 
 // Stop listener and cleanup
@@ -363,6 +523,9 @@ const sampleConfig = `
  ##  transport only.
  # tls_allowed_cacerts = ["/etc/telegraf/clientca.pem"]
 
+ ## Define (for certain nested telemetry measurements with embedded tags) which fields are tags
+ # embedded_tags = ["Cisco-IOS-XR-qos-ma-oper:qos/interface-table/interface/input/service-policy-names/service-policy-instance/statistics/class-stats/class-name"]
+
  ## Define aliases to map telemetry encoding paths to simple measurement names
  [inputs.cisco_telemetry_mdt.aliases]
    ifstats = "ietf-interfaces:interfaces-state/interface/statistics"

plugins/inputs/cisco_telemetry_mdt/cisco_telemetry_mdt_test.go

@@ -17,23 +17,6 @@ import (
 	"google.golang.org/grpc"
 )
 
-func TestHandleTelemetryEmpty(t *testing.T) {
-	c := &CiscoTelemetryMDT{Transport: "dummy"}
-	acc := &testutil.Accumulator{}
-	c.Start(acc)
-
-	telemetry := &telemetry.Telemetry{
-		DataGpbkv: []*telemetry.TelemetryField{
-			{},
-		},
-	}
-	data, _ := proto.Marshal(telemetry)
-
-	c.handleTelemetry(data)
-	assert.Contains(t, acc.Errors, errors.New("empty encoding path or measurement"))
-	assert.Empty(t, acc.Metrics)
-}
-
 func TestHandleTelemetryTwoSimple(t *testing.T) {
 	c := &CiscoTelemetryMDT{Transport: "dummy", Aliases: map[string]string{"alias": "type:model/some/path"}}
 	acc := &testutil.Accumulator{}
@@ -174,6 +157,233 @@ func TestHandleTelemetrySingleNested(t *testing.T) {
 	acc.AssertContainsTaggedFields(t, "nested", fields, tags)
 }
 
+func TestHandleEmbeddedTags(t *testing.T) {
+	c := &CiscoTelemetryMDT{Transport: "dummy", Aliases: map[string]string{"extra": "type:model/extra"}, EmbeddedTags: []string{"type:model/extra/list/name"}}
+	acc := &testutil.Accumulator{}
+	c.Start(acc)
+
+	telemetry := &telemetry.Telemetry{
+		MsgTimestamp: 1543236572000,
+		EncodingPath: "type:model/extra",
+		NodeId:       &telemetry.Telemetry_NodeIdStr{NodeIdStr: "hostname"},
+		Subscription: &telemetry.Telemetry_SubscriptionIdStr{SubscriptionIdStr: "subscription"},
+		DataGpbkv: []*telemetry.TelemetryField{
+			{
+				Fields: []*telemetry.TelemetryField{
+					{
+						Name: "keys",
+						Fields: []*telemetry.TelemetryField{
+							{
+								Name:        "foo",
+								ValueByType: &telemetry.TelemetryField_StringValue{StringValue: "bar"},
+							},
+						},
+					},
+					{
+						Name: "content",
+						Fields: []*telemetry.TelemetryField{
+							{
+								Name: "list",
+								Fields: []*telemetry.TelemetryField{
+									{
+										Name:        "name",
+										ValueByType: &telemetry.TelemetryField_StringValue{StringValue: "entry1"},
+									},
+									{
+										Name:        "test",
+										ValueByType: &telemetry.TelemetryField_StringValue{StringValue: "foo"},
+									},
+								},
+							},
+							{
+								Name: "list",
+								Fields: []*telemetry.TelemetryField{
+									{
+										Name:        "name",
+										ValueByType: &telemetry.TelemetryField_StringValue{StringValue: "entry2"},
+									},
+									{
+										Name:        "test",
+										ValueByType: &telemetry.TelemetryField_StringValue{StringValue: "bar"},
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+	data, _ := proto.Marshal(telemetry)
+
+	c.handleTelemetry(data)
+	assert.Empty(t, acc.Errors)
+
+	tags1 := map[string]string{"path": "type:model/extra", "foo": "bar", "source": "hostname", "subscription": "subscription", "list/name": "entry1"}
+	fields1 := map[string]interface{}{"list/test": "foo"}
+	tags2 := map[string]string{"path": "type:model/extra", "foo": "bar", "source": "hostname", "subscription": "subscription", "list/name": "entry2"}
+	fields2 := map[string]interface{}{"list/test": "bar"}
+	acc.AssertContainsTaggedFields(t, "extra", fields1, tags1)
+	acc.AssertContainsTaggedFields(t, "extra", fields2, tags2)
+}
+
+func TestHandleNXAPI(t *testing.T) {
+	c := &CiscoTelemetryMDT{Transport: "dummy", Aliases: map[string]string{"nxapi": "show nxapi"}}
+	acc := &testutil.Accumulator{}
+	c.Start(acc)
+
+	telemetry := &telemetry.Telemetry{
+		MsgTimestamp: 1543236572000,
+		EncodingPath: "show nxapi",
+		NodeId:       &telemetry.Telemetry_NodeIdStr{NodeIdStr: "hostname"},
+		Subscription: &telemetry.Telemetry_SubscriptionIdStr{SubscriptionIdStr: "subscription"},
+		DataGpbkv: []*telemetry.TelemetryField{
+			{
+				Fields: []*telemetry.TelemetryField{
+					{
+						Name: "keys",
+						Fields: []*telemetry.TelemetryField{
+							{
+								Name:        "foo",
+								ValueByType: &telemetry.TelemetryField_StringValue{StringValue: "bar"},
+							},
+						},
+					},
+					{
+						Name: "content",
+						Fields: []*telemetry.TelemetryField{
+							{
+								Fields: []*telemetry.TelemetryField{
+									{
+										Name: "TABLE_nxapi",
+										Fields: []*telemetry.TelemetryField{
+											{
+												Fields: []*telemetry.TelemetryField{
+													{
+														Name: "ROW_nxapi",
+														Fields: []*telemetry.TelemetryField{
+															{
+																Fields: []*telemetry.TelemetryField{
+																	{
+																		Name:        "index",
+																		ValueByType: &telemetry.TelemetryField_StringValue{StringValue: "i1"},
+																	},
+																	{
+																		Name:        "value",
+																		ValueByType: &telemetry.TelemetryField_StringValue{StringValue: "foo"},
+																	},
+																},
+															},
+															{
+																Fields: []*telemetry.TelemetryField{
+																	{
+																		Name:        "index",
+																		ValueByType: &telemetry.TelemetryField_StringValue{StringValue: "i2"},
+																	},
+																	{
+																		Name:        "value",
+																		ValueByType: &telemetry.TelemetryField_StringValue{StringValue: "bar"},
+																	},
+																},
+															},
+														},
+													},
+												},
+											},
+										},
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+	data, _ := proto.Marshal(telemetry)
+
+	c.handleTelemetry(data)
+	assert.Empty(t, acc.Errors)
+
+	tags1 := map[string]string{"path": "show nxapi", "foo": "bar", "TABLE_nxapi": "i1", "source": "hostname", "subscription": "subscription"}
+	fields1 := map[string]interface{}{"value": "foo"}
+	tags2 := map[string]string{"path": "show nxapi", "foo": "bar", "TABLE_nxapi": "i2", "source": "hostname", "subscription": "subscription"}
+	fields2 := map[string]interface{}{"value": "bar"}
+	acc.AssertContainsTaggedFields(t, "nxapi", fields1, tags1)
+	acc.AssertContainsTaggedFields(t, "nxapi", fields2, tags2)
+}
+
+func TestHandleNXDME(t *testing.T) {
+	c := &CiscoTelemetryMDT{Transport: "dummy", Aliases: map[string]string{"dme": "sys/dme"}}
+	acc := &testutil.Accumulator{}
+	c.Start(acc)
+
+	telemetry := &telemetry.Telemetry{
+		MsgTimestamp: 1543236572000,
+		EncodingPath: "sys/dme",
+		NodeId:       &telemetry.Telemetry_NodeIdStr{NodeIdStr: "hostname"},
+		Subscription: &telemetry.Telemetry_SubscriptionIdStr{SubscriptionIdStr: "subscription"},
+		DataGpbkv: []*telemetry.TelemetryField{
+			{
+				Fields: []*telemetry.TelemetryField{
+					{
+						Name: "keys",
+						Fields: []*telemetry.TelemetryField{
+							{
+								Name:        "foo",
+								ValueByType: &telemetry.TelemetryField_StringValue{StringValue: "bar"},
+							},
+						},
+					},
+					{
+						Name: "content",
+						Fields: []*telemetry.TelemetryField{
+							{
+								Fields: []*telemetry.TelemetryField{
+									{
+										Name: "fooEntity",
+										Fields: []*telemetry.TelemetryField{
+											{
+												Fields: []*telemetry.TelemetryField{
+													{
+														Name: "attributes",
+														Fields: []*telemetry.TelemetryField{
+															{
+																Fields: []*telemetry.TelemetryField{
+																	{
+																		Name:        "rn",
+																		ValueByType: &telemetry.TelemetryField_StringValue{StringValue: "some-rn"},
+																	},
+																	{
+																		Name:        "value",
+																		ValueByType: &telemetry.TelemetryField_StringValue{StringValue: "foo"},
+																	},
+																},
+															},
+														},
+													},
+												},
+											},
+										},
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+	data, _ := proto.Marshal(telemetry)
+
+	c.handleTelemetry(data)
+	assert.Empty(t, acc.Errors)
+
+	tags1 := map[string]string{"path": "sys/dme", "foo": "bar", "fooEntity": "some-rn", "source": "hostname", "subscription": "subscription"}
+	fields1 := map[string]interface{}{"value": "foo"}
+	acc.AssertContainsTaggedFields(t, "dme", fields1, tags1)
+}
+
 func TestTCPDialoutOverflow(t *testing.T) {
 	c := &CiscoTelemetryMDT{Transport: "tcp", ServiceAddress: "127.0.0.1:57000"}
 	acc := &testutil.Accumulator{}