feat(processors.parser): Add option to parse tags

plugins/processors/parser/README.md

@@ -1,21 +1,25 @@
 # Parser Processor Plugin
 
-This plugin parses defined fields containing the specified data format and
-creates new metrics based on the contents of the field.
+This plugin parses defined fields or tags containing the specified data format
+and creates new metrics based on the contents of the field or tag.
 
 ## Configuration
 
 ```toml @sample.conf
-# Parse a value in a specified field/tag(s) and add the result in a new metric
+# Parse a value in a specified field(s)/tag(s) and add the result in a new metric
 [[processors.parser]]
   ## The name of the fields whose value will be parsed.
   parse_fields = ["message"]
 
+  ## The name of the tags whose value will be parsed.
+  # parse_tags = []
+
   ## If true, incoming metrics are not emitted.
-  drop_original = false
+  # drop_original = false
 
   ## If set to override, emitted metrics will be merged by overriding the
   ## original metric using the newly parsed metrics.
+  ## Only has effect when drop_original is set to false.
   merge = "override"
 
   ## The dataformat to be read from files

plugins/processors/parser/parser.go

@@ -20,6 +20,7 @@ type Parser struct {
 	DropOriginal bool            `toml:"drop_original"`
 	Merge        string          `toml:"merge"`
 	ParseFields  []string        `toml:"parse_fields"`
+	ParseTags    []string        `toml:"parse_tags"`
 	Log          telegraf.Logger `toml:"-"`
 	parser       telegraf.Parser
 }
@@ -47,12 +48,13 @@ func (p *Parser) Apply(metrics ...telegraf.Metric) []telegraf.Metric {
 			newMetrics = append(newMetrics, metric)
 		}
 
+		// parse fields
 		for _, key := range p.ParseFields {
 			for _, field := range metric.FieldList() {
 				if field.Key == key {
 					switch value := field.Value.(type) {
 					case string:
-						fromFieldMetric, err := p.parseField(value)
+						fromFieldMetric, err := p.parseValue(value)
 						if err != nil {
 							p.Log.Errorf("could not parse field %s: %v", key, err)
 						}
@@ -74,6 +76,24 @@ func (p *Parser) Apply(metrics ...telegraf.Metric) []telegraf.Metric {
 			}
 		}
 
+		// parse tags
+		for _, key := range p.ParseTags {
+			if value, ok := metric.GetTag(key); ok {
+				fromTagMetric, err := p.parseValue(value)
+				if err != nil {
+					p.Log.Errorf("could not parse tag %s: %v", key, err)
+				}
+
+				for _, m := range fromTagMetric {
+					if m.Name() == "" {
+						m.SetName(metric.Name())
+					}
+				}
+
+				newMetrics = append(newMetrics, fromTagMetric...)
+			}
+		}
+
 		if len(newMetrics) == 0 {
 			continue
 		}
@@ -100,7 +120,7 @@ func merge(base telegraf.Metric, metrics []telegraf.Metric) telegraf.Metric {
 	return base
 }
 
-func (p *Parser) parseField(value string) ([]telegraf.Metric, error) {
+func (p *Parser) parseValue(value string) ([]telegraf.Metric, error) {
 	return p.parser.Parse([]byte(value))
 }
 

plugins/processors/parser/parser_test.go

@@ -12,24 +12,13 @@ import (
 	_ "github.com/influxdata/telegraf/plugins/parsers/all"
 
 	"github.com/influxdata/telegraf/testutil"
-
-	"github.com/stretchr/testify/require"
 )
 
-// compares metrics without comparing time
-func compareMetrics(t *testing.T, expected, actual []telegraf.Metric) {
-	require.Equal(t, len(expected), len(actual))
-	for i, m := range actual {
-		require.Equal(t, expected[i].Name(), m.Name())
-		require.Equal(t, expected[i].Fields(), m.Fields())
-		require.Equal(t, expected[i].Tags(), m.Tags())
-	}
-}
-
 func TestApply(t *testing.T) {
 	tests := []struct {
 		name         string
 		parseFields  []string
+		parseTags    []string
 		config       parsers.Config
 		dropOriginal bool
 		merge        string
@@ -361,6 +350,93 @@ func TestApply(t *testing.T) {
 					time.Unix(0, 0)),
 			},
 		},
+		{
+			name:         "parse one tag drop original",
+			parseTags:    []string{"sample"},
+			dropOriginal: true,
+			config: parsers.Config{
+				DataFormat: "logfmt",
+			},
+			input: metric.New(
+				"singleTag",
+				map[string]string{
+					"some":   "tag",
+					"sample": `ts=2018-07-24T19:43:40.275Z`,
+				},
+				map[string]interface{}{},
+				time.Unix(0, 0)),
+			expected: []telegraf.Metric{
+				metric.New(
+					"singleTag",
+					map[string]string{},
+					map[string]interface{}{
+						"ts": "2018-07-24T19:43:40.275Z",
+					},
+					time.Unix(0, 0)),
+			},
+		},
+		{
+			name:         "parse one tag with merge",
+			parseTags:    []string{"sample"},
+			dropOriginal: false,
+			merge:        "override",
+			config: parsers.Config{
+				DataFormat: "logfmt",
+			},
+			input: metric.New(
+				"singleTag",
+				map[string]string{
+					"some":   "tag",
+					"sample": `ts=2018-07-24T19:43:40.275Z`,
+				},
+				map[string]interface{}{},
+				time.Unix(0, 0)),
+			expected: []telegraf.Metric{
+				metric.New(
+					"singleTag",
+					map[string]string{
+						"some":   "tag",
+						"sample": `ts=2018-07-24T19:43:40.275Z`,
+					},
+					map[string]interface{}{
+						"ts": "2018-07-24T19:43:40.275Z",
+					},
+					time.Unix(0, 0)),
+			},
+		},
+		{
+			name:         "parse one tag keep",
+			parseTags:    []string{"sample"},
+			dropOriginal: false,
+			config: parsers.Config{
+				DataFormat: "logfmt",
+			},
+			input: metric.New(
+				"singleTag",
+				map[string]string{
+					"some":   "tag",
+					"sample": `ts=2018-07-24T19:43:40.275Z`,
+				},
+				map[string]interface{}{},
+				time.Unix(0, 0)),
+			expected: []telegraf.Metric{
+				metric.New(
+					"singleTag",
+					map[string]string{
+						"some":   "tag",
+						"sample": `ts=2018-07-24T19:43:40.275Z`,
+					},
+					map[string]interface{}{},
+					time.Unix(0, 0)),
+				metric.New(
+					"singleTag",
+					map[string]string{},
+					map[string]interface{}{
+						"ts": "2018-07-24T19:43:40.275Z",
+					},
+					time.Unix(0, 0)),
+			},
+		},
 		{
 			name:         "Fail to parse one field but parses other [keep]",
 			parseFields:  []string{"good", "bad"},
@@ -506,14 +582,15 @@ func TestApply(t *testing.T) {
 			parser := Parser{
 				Config:       tt.config,
 				ParseFields:  tt.parseFields,
+				ParseTags:    tt.parseTags,
 				DropOriginal: tt.dropOriginal,
 				Merge:        tt.merge,
 				Log:          testutil.Logger{Name: "processor.parser"},
 			}
 
 			output := parser.Apply(tt.input)
 			t.Logf("Testing: %s", tt.name)
-			compareMetrics(t, tt.expected, output)
+			testutil.RequireMetricsEqual(t, tt.expected, output, testutil.IgnoreTime())
 		})
 	}
 }
@@ -584,7 +661,7 @@ func TestBadApply(t *testing.T) {
 
 			output := parser.Apply(tt.input)
 
-			compareMetrics(t, output, tt.expected)
+			testutil.RequireMetricsEqual(t, tt.expected, output, testutil.IgnoreTime())
 		})
 	}
 }

plugins/processors/parser/sample.conf

@@ -1,13 +1,17 @@
-# Parse a value in a specified field/tag(s) and add the result in a new metric
+# Parse a value in a specified field(s)/tag(s) and add the result in a new metric
 [[processors.parser]]
   ## The name of the fields whose value will be parsed.
   parse_fields = ["message"]
 
+  ## The name of the tags whose value will be parsed.
+  # parse_tags = []
+
   ## If true, incoming metrics are not emitted.
-  drop_original = false
+  # drop_original = false
 
   ## If set to override, emitted metrics will be merged by overriding the
   ## original metric using the newly parsed metrics.
+  ## Only has effect when drop_original is set to false.
   merge = "override"
 
   ## The dataformat to be read from files