Add wildcard tags json parser support (#8579)

plugins/parsers/json/README.md

@@ -30,10 +30,12 @@ ignored unless specified in the `tag_key` or `json_string_fields` options.
   json_query = ""
 
   ## Tag keys is an array of keys that should be added as tags.  Matching keys
-  ## are no longer saved as fields.
+  ## are no longer saved as fields. Supports wildcard glob matching.
   tag_keys = [
     "my_tag_1",
-    "my_tag_2"
+    "my_tag_2",
+    "tags_*",
+    "tag*"
   ]
 
   ## Array of glob pattern strings or booleans keys that should be added as string fields.

plugins/parsers/json/parser.go

@@ -36,7 +36,7 @@ type Config struct {
 
 type Parser struct {
 	metricName   string
-	tagKeys      []string
+	tagKeys      filter.Filter
 	stringFields filter.Filter
 	nameKey      string
 	query        string
@@ -53,9 +53,14 @@ func New(config *Config) (*Parser, error) {
 		return nil, err
 	}
 
+	tagKeyFilter, err := filter.Compile(config.TagKeys)
+	if err != nil {
+		return nil, err
+	}
+
 	return &Parser{
 		metricName:   config.MetricName,
-		tagKeys:      config.TagKeys,
+		tagKeys:      tagKeyFilter,
 		nameKey:      config.NameKey,
 		stringFields: stringFilter,
 		query:        config.Query,
@@ -104,15 +109,15 @@ func (p *Parser) parseObject(data map[string]interface{}, timestamp time.Time) (
 
 	name := p.metricName
 
-	//checks if json_name_key is set
+	// checks if json_name_key is set
 	if p.nameKey != "" {
 		switch field := f.Fields[p.nameKey].(type) {
 		case string:
 			name = field
 		}
 	}
 
-	//if time key is specified, set timestamp to it
+	// if time key is specified, set timestamp to it
 	if p.timeKey != "" {
 		if p.timeFormat == "" {
 			err := fmt.Errorf("use of 'json_time_key' requires 'json_time_format'")
@@ -131,7 +136,7 @@ func (p *Parser) parseObject(data map[string]interface{}, timestamp time.Time) (
 
 		delete(f.Fields, p.timeKey)
 
-		//if the year is 0, set to current year
+		// if the year is 0, set to current year
 		if timestamp.Year() == 0 {
 			timestamp = timestamp.AddDate(time.Now().Year(), 0, 0)
 		}
@@ -145,32 +150,37 @@ func (p *Parser) parseObject(data map[string]interface{}, timestamp time.Time) (
 	return []telegraf.Metric{metric}, nil
 }
 
-//will take in field map with strings and bools,
-//search for TagKeys that match fieldnames and add them to tags
-//will delete any strings/bools that shouldn't be fields
-//assumes that any non-numeric values in TagKeys should be displayed as tags
+// will take in field map with strings and bools,
+// search for TagKeys that match fieldnames and add them to tags
+// will delete any strings/bools that shouldn't be fields
+// assumes that any non-numeric values in TagKeys should be displayed as tags
 func (p *Parser) switchFieldToTag(tags map[string]string, fields map[string]interface{}) (map[string]string, map[string]interface{}) {
-	for _, name := range p.tagKeys {
-		//switch any fields in tagkeys into tags
-		if fields[name] == nil {
+
+	for name, value := range fields {
+		if p.tagKeys == nil {
+			continue
+		}
+		// skip switch statement if tagkey doesn't match fieldname
+		if !p.tagKeys.Match(name) {
 			continue
 		}
-		switch value := fields[name].(type) {
+		// switch any fields in tagkeys into tags
+		switch t := value.(type) {
 		case string:
-			tags[name] = value
+			tags[name] = t
 			delete(fields, name)
 		case bool:
-			tags[name] = strconv.FormatBool(value)
+			tags[name] = strconv.FormatBool(t)
 			delete(fields, name)
 		case float64:
-			tags[name] = strconv.FormatFloat(value, 'f', -1, 64)
+			tags[name] = strconv.FormatFloat(t, 'f', -1, 64)
 			delete(fields, name)
 		default:
 			log.Printf("E! [parsers.json] Unrecognized type %T", value)
 		}
 	}
 
-	//remove any additional string/bool values from fields
+	// remove any additional string/bool values from fields
 	for fk := range fields {
 		switch fields[fk].(type) {
 		case string, bool: