feat(inputs.net): Add speed metric

plugins/inputs/net/README.md

@@ -47,6 +47,7 @@ Fields (all platforms):
 * err_out - The total number of transmit errors detected by the interface
 * drop_in - The total number of received packets dropped by the interface
 * drop_out - The total number of transmitted packets dropped by the interface
+* speed - The interface's latest or current speed value, in Mbits/sec. May be zero if unsupported by the interface or platform
 
 Different platforms gather the data above with different mechanisms. Telegraf
 uses the ([gopsutil](https://github.com/shirou/gopsutil)) package, which under

plugins/inputs/net/net.go

@@ -5,6 +5,9 @@ import (
 	_ "embed"
 	"fmt"
 	"net"
+	"os"
+	"path/filepath"
+	"strconv"
 	"strings"
 
 	"github.com/influxdata/telegraf"
@@ -104,6 +107,7 @@ func (n *NetIOStats) Gather(acc telegraf.Accumulator) error {
 			"err_out":      io.Errout,
 			"drop_in":      io.Dropin,
 			"drop_out":     io.Dropout,
+			"speed":        getInterfaceSpeed(io.Name),
 		}
 		acc.AddCounter("net", fields, tags)
 	}
@@ -129,6 +133,29 @@ func (n *NetIOStats) Gather(acc telegraf.Accumulator) error {
 	return nil
 }
 
+func getInterfaceSpeed(ioName string) uint64 {
+	sysPath := os.Getenv("HOST_SYS")
+	if sysPath == "" {
+		sysPath = "/sys"
+	}
+
+	raw, err := os.ReadFile(filepath.Join(sysPath, "class", "net", ioName, "speed"))
+	if err != nil {
+		return 0
+	}
+	speedStr := string(raw)
+
+	if speedStr == "-1" {
+		return 0
+	}
+
+	speed, err := strconv.ParseUint(speedStr, 10, 64)
+	if err != nil {
+		return 0
+	}
+	return speed
+}
+
 func init() {
 	inputs.Add("net", func() telegraf.Input {
 		return &NetIOStats{ps: system.NewSystemPS()}

plugins/inputs/net/net_test.go

@@ -1,6 +1,8 @@
 package net
 
 import (
+	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/influxdata/telegraf/plugins/inputs/system"
@@ -40,6 +42,8 @@ func TestNetIOStats(t *testing.T) {
 	}
 	mps.On("NetProto").Return(netprotos, nil)
 
+	require.NoError(t, os.Setenv("HOST_SYS", filepath.Join("testdata", "general", "sys")))
+
 	err = (&NetIOStats{ps: &mps, skipChecks: true}).Gather(&acc)
 	require.NoError(t, err)
 
@@ -56,6 +60,70 @@ func TestNetIOStats(t *testing.T) {
 		"err_out":      uint64(8),
 		"drop_in":      uint64(7),
 		"drop_out":     uint64(1),
+		"speed":        uint64(100),
+	}
+	acc.AssertContainsTaggedFields(t, "net", fields1, ntags)
+
+	fields2 := map[string]interface{}{
+		"udp_noports":     int64(892592),
+		"udp_indatagrams": int64(4655),
+	}
+	ntags = map[string]string{
+		"interface": "all",
+	}
+	acc.AssertContainsTaggedFields(t, "net", fields2, ntags)
+}
+
+func TestNetIOStatsNoSpeedFile(t *testing.T) {
+	var mps system.MockPS
+	var err error
+	defer mps.AssertExpectations(t)
+	var acc testutil.Accumulator
+
+	netio := net.IOCountersStat{
+		Name:        "eth1",
+		BytesSent:   1123,
+		BytesRecv:   8734422,
+		PacketsSent: 781,
+		PacketsRecv: 23456,
+		Errin:       832,
+		Errout:      8,
+		Dropin:      7,
+		Dropout:     1,
+	}
+
+	mps.On("NetIO").Return([]net.IOCountersStat{netio}, nil)
+
+	netprotos := []net.ProtoCountersStat{
+		{
+			Protocol: "Udp",
+			Stats: map[string]int64{
+				"InDatagrams": 4655,
+				"NoPorts":     892592,
+			},
+		},
+	}
+	mps.On("NetProto").Return(netprotos, nil)
+
+	require.NoError(t, os.Setenv("HOST_SYS", filepath.Join("testdata", "general", "sys")))
+
+	err = (&NetIOStats{ps: &mps, skipChecks: true}).Gather(&acc)
+	require.NoError(t, err)
+
+	ntags := map[string]string{
+		"interface": "eth1",
+	}
+
+	fields1 := map[string]interface{}{
+		"bytes_sent":   uint64(1123),
+		"bytes_recv":   uint64(8734422),
+		"packets_sent": uint64(781),
+		"packets_recv": uint64(23456),
+		"err_in":       uint64(832),
+		"err_out":      uint64(8),
+		"drop_in":      uint64(7),
+		"drop_out":     uint64(1),
+		"speed":        uint64(0),
 	}
 	acc.AssertContainsTaggedFields(t, "net", fields1, ntags)
 

plugins/inputs/net/testdata/general/sys/class/net/eth0/speed

@@ -0,0 +1 @@
+100