Add configurable separator graphite serializer and output (#7545)

plugins/serializers/graphite/graphite.go

@@ -39,6 +39,7 @@ type GraphiteSerializer struct {
 	Prefix     string
 	Template   string
 	TagSupport bool
+	Separator  string
 	Templates  []*GraphiteTemplate
 }
 
@@ -55,7 +56,7 @@ func (s *GraphiteSerializer) Serialize(metric telegraf.Metric) ([]byte, error) {
 			if fieldValue == "" {
 				continue
 			}
-			bucket := SerializeBucketNameWithTags(metric.Name(), metric.Tags(), s.Prefix, fieldName)
+			bucket := SerializeBucketNameWithTags(metric.Name(), metric.Tags(), s.Prefix, s.Separator, fieldName)
 			metricString := fmt.Sprintf("%s %s %d\n",
 				// insert "field" section of template
 				bucket,
@@ -246,6 +247,7 @@ func SerializeBucketNameWithTags(
 	measurement string,
 	tags map[string]string,
 	prefix string,
+	separator string,
 	field string,
 ) string {
 	var out string
@@ -259,13 +261,13 @@ func SerializeBucketNameWithTags(
 	sort.Strings(tagsCopy)
 
 	if prefix != "" {
-		out = prefix + "."
+		out = prefix + separator
 	}
 
 	out += measurement
 
 	if field != "value" {
-		out += "." + field
+		out += separator + field
 	}
 
 	out = sanitize(out)