added config flag to skip collection of network protocol metrics

plugins/inputs/system/NET_README.md

@@ -14,6 +14,11 @@ This plugin gathers metrics about network interface and protocol usage (Linux on
   ##
   # interfaces = ["eth*", "enp0s[0-1]", "lo"]
   ##
+  ## On linux systems telegraf also collects protocol stats.
+  ## Setting ignore_protocol_stats to true will skip reporting of protocol metrics.
+  ##
+  # ignore_protocol_stats = false
+  ##
 ```
 
 ### Measurements & Fields:

plugins/inputs/system/net.go

@@ -14,8 +14,9 @@ type NetIOStats struct {
 	filter filter.Filter
 	ps     PS
 
-	skipChecks bool
-	Interfaces []string
+	skipChecks          bool
+	IgnoreProtocolStats bool
+	Interfaces          []string
 }
 
 func (_ *NetIOStats) Description() string {
@@ -28,6 +29,12 @@ var netSampleConfig = `
   ## regardless of status.
   ##
   # interfaces = ["eth0"]
+  ##
+  ## On linux systems telegraf also collects protocol stats.
+  ## Setting ignore_protocol_stats to true will skip reporting of protocol metrics.
+  ##
+  # ignore_protocol_stats = false
+  ##
 `
 
 func (_ *NetIOStats) SampleConfig() string {
@@ -91,19 +98,21 @@ func (s *NetIOStats) Gather(acc telegraf.Accumulator) error {
 
 	// Get system wide stats for different network protocols
 	// (ignore these stats if the call fails)
-	netprotos, _ := s.ps.NetProto()
-	fields := make(map[string]interface{})
-	for _, proto := range netprotos {
-		for stat, value := range proto.Stats {
-			name := fmt.Sprintf("%s_%s", strings.ToLower(proto.Protocol),
-				strings.ToLower(stat))
-			fields[name] = value
+	if !s.IgnoreProtocolStats {
+		netprotos, _ := s.ps.NetProto()
+		fields := make(map[string]interface{})
+		for _, proto := range netprotos {
+			for stat, value := range proto.Stats {
+				name := fmt.Sprintf("%s_%s", strings.ToLower(proto.Protocol),
+					strings.ToLower(stat))
+				fields[name] = value
+			}
 		}
+		tags := map[string]string{
+			"interface": "all",
+		}
+		acc.AddFields("net", fields, tags)
 	}
-	tags := map[string]string{
-		"interface": "all",
-	}
-	acc.AddFields("net", fields, tags)
 
 	return nil
 }

plugins/inputs/system/net_test.go

@@ -106,4 +106,10 @@ func TestNetStats(t *testing.T) {
 		"udp_socket":      1,
 	}
 	acc.AssertContainsTaggedFields(t, "netstat", fields3, make(map[string]string))
+
+	acc.Metrics = nil
+	err = (&NetIOStats{ps: &mps, IgnoreProtocolStats: true}).Gather(&acc)
+	require.NoError(t, err)
+
+	acc.AssertDoesNotContainsTaggedFields(t, "netstat", fields3, make(map[string]string))
 }