Add ability to set measurement from matched text in grok parser (#4433)

plugins/parsers/grok/parser.go

@@ -38,6 +38,7 @@ var timeLayouts = map[string]string{
 }
 
 const (
+	MEASUREMENT       = "measurement"
 	INT               = "int"
 	TAG               = "tag"
 	FLOAT             = "float"
@@ -217,7 +218,6 @@ func (p *Parser) ParseLine(line string) (telegraf.Metric, error) {
 		if k == "" || v == "" {
 			continue
 		}
-
 		// t is the modifier of the field
 		var t string
 		// check if pattern has some modifiers
@@ -239,6 +239,8 @@ func (p *Parser) ParseLine(line string) (telegraf.Metric, error) {
 		}
 
 		switch t {
+		case MEASUREMENT:
+			p.Measurement = v
 		case INT:
 			iv, err := strconv.ParseInt(v, 10, 64)
 			if err != nil {
@@ -350,7 +352,7 @@ func (p *Parser) ParseLine(line string) (telegraf.Metric, error) {
 	}
 
 	if len(fields) == 0 {
-		return nil, fmt.Errorf("logparser_grok: must have one or more fields")
+		return nil, fmt.Errorf("grok: must have one or more fields")
 	}
 
 	return metric.New(p.Measurement, tags, fields, p.tsModder.tsMod(timestamp))

plugins/parsers/grok/parser_test.go

@@ -1,6 +1,7 @@
 package grok
 
 import (
+	"log"
 	"testing"
 	"time"
 
@@ -959,3 +960,52 @@ func TestReplaceTimestampComma(t *testing.T) {
 	//Convert Nanosecond to milisecond for compare
 	require.Equal(t, 555, m.Time().Nanosecond()/1000000)
 }
+
+func TestDynamicMeasurementModifier(t *testing.T) {
+	p := &Parser{
+		Patterns:       []string{"%{TEST}"},
+		CustomPatterns: "TEST %{NUMBER:var1:tag} %{NUMBER:var2:float} %{WORD:test:measurement}",
+	}
+
+	require.NoError(t, p.Compile())
+	m, err := p.ParseLine("4 5 hello")
+	require.NoError(t, err)
+	require.Equal(t, m.Name(), "hello")
+}
+
+func TestStaticMeasurementModifier(t *testing.T) {
+	p := &Parser{
+		Patterns: []string{"%{WORD:hi:measurement} %{NUMBER:num:string}"},
+	}
+
+	require.NoError(t, p.Compile())
+	m, err := p.ParseLine("test_name 42")
+	log.Printf("%v", m)
+	require.NoError(t, err)
+	require.Equal(t, "test_name", m.Name())
+}
+
+// tests that the top level measurement name is used
+func TestTwoMeasurementModifier(t *testing.T) {
+	p := &Parser{
+		Patterns:       []string{"%{TEST:test_name:measurement}"},
+		CustomPatterns: "TEST %{NUMBER:var1:tag} %{NUMBER:var2:measurement} %{WORD:var3:measurement}",
+	}
+
+	require.NoError(t, p.Compile())
+	m, err := p.ParseLine("4 5 hello")
+	require.NoError(t, err)
+	require.Equal(t, m.Name(), "4 5 hello")
+}
+
+func TestMeasurementModifierNoName(t *testing.T) {
+	p := &Parser{
+		Patterns:       []string{"%{TEST}"},
+		CustomPatterns: "TEST %{NUMBER:var1:tag} %{NUMBER:var2:float} %{WORD:hi:measurement}",
+	}
+
+	require.NoError(t, p.Compile())
+	m, err := p.ParseLine("4 5 hello")
+	require.NoError(t, err)
+	require.Equal(t, m.Name(), "hello")
+}