Carbon2 configuration option - include field in metric name

config/config.go

@@ -1933,6 +1933,14 @@ func buildSerializer(name string, tbl *ast.Table) (serializers.Serializer, error
 		}
 	}
 
+	if node, ok := tbl.Fields["carbon2_format"]; ok {
+		if kv, ok := node.(*ast.KeyValue); ok {
+			if str, ok := kv.Value.(*ast.String); ok {
+				c.Carbon2Format = str.Value
+			}
+		}
+	}
+
 	if node, ok := tbl.Fields["influx_max_line_bytes"]; ok {
 		if kv, ok := node.(*ast.KeyValue); ok {
 			if integer, ok := kv.Value.(*ast.Integer); ok {
@@ -2089,6 +2097,7 @@ func buildSerializer(name string, tbl *ast.Table) (serializers.Serializer, error
 		}
 	}
 
+	delete(tbl.Fields, "carbon2_format")
 	delete(tbl.Fields, "influx_max_line_bytes")
 	delete(tbl.Fields, "influx_sort_fields")
 	delete(tbl.Fields, "influx_uint_support")

plugins/outputs/sumologic/sumologic_test.go

@@ -133,7 +133,7 @@ func TestMethod(t *testing.T) {
 				w.WriteHeader(http.StatusOK)
 			})
 
-			serializer, err := carbon2.NewSerializer()
+			serializer, err := carbon2.NewSerializer(carbon2.Carbon2FormatFieldSeparate)
 			require.NoError(t, err)
 
 			plugin := tt.plugin()
@@ -210,7 +210,7 @@ func TestStatusCode(t *testing.T) {
 				w.WriteHeader(tt.statusCode)
 			})
 
-			serializer, err := carbon2.NewSerializer()
+			serializer, err := carbon2.NewSerializer(carbon2.Carbon2FormatFieldSeparate)
 			require.NoError(t, err)
 
 			tt.plugin.SetSerializer(serializer)
@@ -234,7 +234,7 @@ func TestContentType(t *testing.T) {
 	u, err := url.Parse(fmt.Sprintf("http://%s", ts.Listener.Addr().String()))
 	require.NoError(t, err)
 
-	carbon2Serializer, err := carbon2.NewSerializer()
+	carbon2Serializer, err := carbon2.NewSerializer(carbon2.Carbon2FormatFieldSeparate)
 	require.NoError(t, err)
 
 	tests := []struct {
@@ -336,7 +336,7 @@ func TestContentEncodingGzip(t *testing.T) {
 				w.WriteHeader(http.StatusNoContent)
 			})
 
-			serializer, err := carbon2.NewSerializer()
+			serializer, err := carbon2.NewSerializer(carbon2.Carbon2FormatFieldSeparate)
 			require.NoError(t, err)
 
 			plugin := tt.plugin()
@@ -372,7 +372,7 @@ func TestDefaultUserAgent(t *testing.T) {
 			MaxRequstBodySize: Default().MaxRequstBodySize,
 		}
 
-		serializer, err := carbon2.NewSerializer()
+		serializer, err := carbon2.NewSerializer(carbon2.Carbon2FormatFieldSeparate)
 		require.NoError(t, err)
 
 		plugin.SetSerializer(serializer)
@@ -555,7 +555,7 @@ func TestMaxRequestBodySize(t *testing.T) {
 				w.WriteHeader(http.StatusOK)
 			})
 
-			serializer, err := carbon2.NewSerializer()
+			serializer, err := carbon2.NewSerializer(carbon2.Carbon2FormatFieldSeparate)
 			require.NoError(t, err)
 
 			plugin := tt.plugin()

plugins/serializers/carbon2/README.md

@@ -2,7 +2,7 @@
 
 The `carbon2` serializer translates the Telegraf metric format to the [Carbon2 format](http://metrics20.org/implementations/).
 
-### Configuration
+## Configuration
 
 ```toml
 [[outputs.file]]
@@ -14,20 +14,51 @@ The `carbon2` serializer translates the Telegraf metric format to the [Carbon2 f
   ## more about them here:
   ## https://github.com/influxdata/telegraf/blob/master/docs/DATA_FORMATS_OUTPUT.md
   data_format = "carbon2"
+
+  ## Optionally configure metrics format, whether to merge metric name and field name.
+  ## Possible options:
+  ## * "field_separate"
+  ## * "metric_includes_field"
+  ## * "" - defaults to "field_separate"
+  # carbon2_format = "field_separate"
 ```
 
 Standard form:
+
 ```
 metric=name field=field_1 host=foo  30 1234567890
 metric=name field=field_2 host=foo  4 1234567890
 metric=name field=field_N host=foo  59 1234567890
 ```
 
-### Metrics
+### Metrics format
+
+`Carbon2` serializer has a configuration option - `carbon2_format` - to change how
+metrics names are being constructed.
 
-The serializer converts the metrics by creating `intrinsic_tags` using the combination of metric name and fields.  So, if one Telegraf metric has 4 fields, the `carbon2` output will be 4 separate metrics. There will be a `metric` tag that represents the name of the metric and a `field` tag to represent the field.
+By default `metric` will only inclue the metric name and a separate field `field`
+will contain the field name.
+This is the behavior of `carbon2_format = "field_separate"` which is the default
+behavior (even if unspecified).
 
-### Example
+Optionally user can opt in to change this to make the metric inclue the field name
+after the `_`.
+This is the behavior of `carbon2_format = "metric_includes_field"` which would
+make the above example look like:
+
+```
+metric=name_field_1 host=foo  30 1234567890
+metric=name_field_2 host=foo  4 1234567890
+metric=name_field_N host=foo  59 1234567890
+```
+
+## Metrics
+
+The serializer converts the metrics by creating `intrinsic_tags` using the combination of metric name and fields.
+So, if one Telegraf metric has 4 fields, the `carbon2` output will be 4 separate metrics.
+There will be a `metric` tag that represents the name of the metric and a `field` tag to represent the field.
+
+## Example
 
 If we take the following InfluxDB Line Protocol:
 
@@ -42,8 +73,10 @@ metric=weather field=temperature location=us-midwest season=summer  82 123456789
 metric=weather field=wind location=us-midwest season=summer  100 1234567890
 ```
 
-### Fields and Tags with spaces
+## Fields and Tags with spaces
+
 When a field key or tag key/value have spaces, spaces will be replaced with `_`.
 
-### Tags with empty values
+## Tags with empty values
+
 When a tag's value is empty, it will be replaced with `null`

plugins/serializers/carbon2/carbon2.go

@@ -9,12 +9,39 @@ import (
 	"github.com/influxdata/telegraf"
 )
 
+type format string
+
+const (
+	Carbon2FormatFieldSeparate       string = "field_separate"
+	Carbon2FormatMetricIncludesField string = "metric_includes_field"
+
+	formatFieldSeparate       = format(Carbon2FormatFieldSeparate)
+	formatMetricIncludesField = format(Carbon2FormatMetricIncludesField)
+)
+
+var formats = map[string]format{
+	// Field separate is the default when no format specified.
+	"":                               formatFieldSeparate,
+	Carbon2FormatFieldSeparate:       formatFieldSeparate,
+	Carbon2FormatMetricIncludesField: formatMetricIncludesField,
+}
+
 type Serializer struct {
+	metricsFormat format
 }
 
-func NewSerializer() (*Serializer, error) {
-	s := &Serializer{}
-	return s, nil
+func NewSerializer(f string) (*Serializer, error) {
+	var (
+		ok            bool
+		metricsFormat format
+	)
+	if metricsFormat, ok = formats[f]; !ok {
+		return nil, fmt.Errorf("unknown carbon2 format: %s", f)
+	}
+
+	return &Serializer{
+		metricsFormat: metricsFormat,
+	}, nil
 }
 
 func (s *Serializer) Serialize(metric telegraf.Metric) ([]byte, error) {
@@ -32,32 +59,54 @@ func (s *Serializer) SerializeBatch(metrics []telegraf.Metric) ([]byte, error) {
 func (s *Serializer) createObject(metric telegraf.Metric) []byte {
 	var m bytes.Buffer
 	for fieldName, fieldValue := range metric.Fields() {
-		if isNumeric(fieldValue) {
-			m.WriteString("metric=")
-			m.WriteString(strings.Replace(metric.Name(), " ", "_", -1))
-			m.WriteString(" field=")
-			m.WriteString(strings.Replace(fieldName, " ", "_", -1))
-			m.WriteString(" ")
-			for _, tag := range metric.TagList() {
-				m.WriteString(strings.Replace(tag.Key, " ", "_", -1))
-				m.WriteString("=")
-				value := tag.Value
-				if len(value) == 0 {
-					value = "null"
-				}
-				m.WriteString(strings.Replace(value, " ", "_", -1))
-				m.WriteString(" ")
+		if !isNumeric(fieldValue) {
+			continue
+		}
+
+		switch s.metricsFormat {
+		case formatFieldSeparate:
+			m.WriteString(serializeMetricFieldSeparate(
+				metric.Name(), fieldName,
+			))
+		case formatMetricIncludesField:
+			m.WriteString(serializeMetricIncludeField(
+				metric.Name(), fieldName,
+			))
+		}
+
+		for _, tag := range metric.TagList() {
+			m.WriteString(strings.Replace(tag.Key, " ", "_", -1))
+			m.WriteString("=")
+			value := tag.Value
+			if len(value) == 0 {
+				value = "null"
 			}
+			m.WriteString(strings.Replace(value, " ", "_", -1))
 			m.WriteString(" ")
-			m.WriteString(fmt.Sprintf("%v", fieldValue))
-			m.WriteString(" ")
-			m.WriteString(strconv.FormatInt(metric.Time().Unix(), 10))
-			m.WriteString("\n")
 		}
+		m.WriteString(" ")
+		m.WriteString(fmt.Sprintf("%v", fieldValue))
+		m.WriteString(" ")
+		m.WriteString(strconv.FormatInt(metric.Time().Unix(), 10))
+		m.WriteString("\n")
 	}
 	return m.Bytes()
 }
 
+func serializeMetricFieldSeparate(name, fieldName string) string {
+	return fmt.Sprintf("metric=%s field=%s ",
+		strings.Replace(name, " ", "_", -1),
+		strings.Replace(fieldName, " ", "_", -1),
+	)
+}
+
+func serializeMetricIncludeField(name, fieldName string) string {
+	return fmt.Sprintf("metric=%s_%s ",
+		strings.Replace(name, " ", "_", -1),
+		strings.Replace(fieldName, " ", "_", -1),
+	)
+}
+
 func isNumeric(v interface{}) bool {
 	switch v.(type) {
 	case string: