Support string field glob matching in json parser (#6102)

plugins/parsers/json/README.md

@@ -31,7 +31,7 @@ ignored unless specified in the `tag_key` or `json_string_fields` options.
     "my_tag_2"
   ]
 
-  ## String fields is an array of keys that should be added as string fields.
+  ## Array of glob pattern strings keys that should be added as string fields.
   json_string_fields = []
 
   ## Name key is the key to use as the measurement name.

plugins/parsers/json/parser.go

@@ -9,30 +9,61 @@ import (
 	"strings"
 	"time"
 
-	"github.com/tidwall/gjson"
-
 	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/filter"
 	"github.com/influxdata/telegraf/internal"
 	"github.com/influxdata/telegraf/metric"
+	"github.com/tidwall/gjson"
 )
 
 var (
 	utf8BOM = []byte("\xef\xbb\xbf")
 )
 
-type JSONParser struct {
-	MetricName     string
-	TagKeys        []string
-	StringFields   []string
-	JSONNameKey    string
-	JSONQuery      string
-	JSONTimeKey    string
-	JSONTimeFormat string
-	JSONTimezone   string
-	DefaultTags    map[string]string
+type Config struct {
+	MetricName   string
+	TagKeys      []string
+	NameKey      string
+	StringFields []string
+	Query        string
+	TimeKey      string
+	TimeFormat   string
+	Timezone     string
+	DefaultTags  map[string]string
+}
+
+type Parser struct {
+	metricName   string
+	tagKeys      []string
+	stringFields filter.Filter
+	nameKey      string
+	query        string
+	timeKey      string
+	timeFormat   string
+	timezone     string
+	defaultTags  map[string]string
+}
+
+func New(config *Config) (*Parser, error) {
+	stringFilter, err := filter.Compile(config.StringFields)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Parser{
+		metricName:   config.MetricName,
+		tagKeys:      config.TagKeys,
+		nameKey:      config.NameKey,
+		stringFields: stringFilter,
+		query:        config.Query,
+		timeKey:      config.TimeKey,
+		timeFormat:   config.TimeFormat,
+		timezone:     config.Timezone,
+		defaultTags:  config.DefaultTags,
+	}, nil
 }
 
-func (p *JSONParser) parseArray(buf []byte) ([]telegraf.Metric, error) {
+func (p *Parser) parseArray(buf []byte) ([]telegraf.Metric, error) {
 	metrics := make([]telegraf.Metric, 0)
 
 	var jsonOut []map[string]interface{}
@@ -50,9 +81,9 @@ func (p *JSONParser) parseArray(buf []byte) ([]telegraf.Metric, error) {
 	return metrics, nil
 }
 
-func (p *JSONParser) parseObject(metrics []telegraf.Metric, jsonOut map[string]interface{}) ([]telegraf.Metric, error) {
+func (p *Parser) parseObject(metrics []telegraf.Metric, jsonOut map[string]interface{}) ([]telegraf.Metric, error) {
 	tags := make(map[string]string)
-	for k, v := range p.DefaultTags {
+	for k, v := range p.defaultTags {
 		tags[k] = v
 	}
 
@@ -62,33 +93,35 @@ func (p *JSONParser) parseObject(metrics []telegraf.Metric, jsonOut map[string]i
 		return nil, err
 	}
 
+	name := p.metricName
+
 	//checks if json_name_key is set
-	if p.JSONNameKey != "" {
-		switch field := f.Fields[p.JSONNameKey].(type) {
+	if p.nameKey != "" {
+		switch field := f.Fields[p.nameKey].(type) {
 		case string:
-			p.MetricName = field
+			name = field
 		}
 	}
 
 	//if time key is specified, set it to nTime
 	nTime := time.Now().UTC()
-	if p.JSONTimeKey != "" {
-		if p.JSONTimeFormat == "" {
+	if p.timeKey != "" {
+		if p.timeFormat == "" {
 			err := fmt.Errorf("use of 'json_time_key' requires 'json_time_format'")
 			return nil, err
 		}
 
-		if f.Fields[p.JSONTimeKey] == nil {
+		if f.Fields[p.timeKey] == nil {
 			err := fmt.Errorf("JSON time key could not be found")
 			return nil, err
 		}
 
-		nTime, err = internal.ParseTimestampWithLocation(f.Fields[p.JSONTimeKey], p.JSONTimeFormat, p.JSONTimezone)
+		nTime, err = internal.ParseTimestampWithLocation(f.Fields[p.timeKey], p.timeFormat, p.timezone)
 		if err != nil {
 			return nil, err
 		}
 
-		delete(f.Fields, p.JSONTimeKey)
+		delete(f.Fields, p.timeKey)
 
 		//if the year is 0, set to current year
 		if nTime.Year() == 0 {
@@ -97,7 +130,7 @@ func (p *JSONParser) parseObject(metrics []telegraf.Metric, jsonOut map[string]i
 	}
 
 	tags, nFields := p.switchFieldToTag(tags, f.Fields)
-	metric, err := metric.New(p.MetricName, tags, nFields, nTime)
+	metric, err := metric.New(name, tags, nFields, nTime)
 	if err != nil {
 		return nil, err
 	}
@@ -108,8 +141,8 @@ func (p *JSONParser) parseObject(metrics []telegraf.Metric, jsonOut map[string]i
 //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 *JSONParser) switchFieldToTag(tags map[string]string, fields map[string]interface{}) (map[string]string, map[string]interface{}) {
-	for _, name := range p.TagKeys {
+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 {
 			continue
@@ -130,31 +163,23 @@ func (p *JSONParser) switchFieldToTag(tags map[string]string, fields map[string]
 	}
 
 	//remove any additional string/bool values from fields
-	for k := range fields {
-		//check if field is in StringFields
-		sField := false
-		for _, v := range p.StringFields {
-			if v == k {
-				sField = true
-			}
-		}
-		if sField {
-			continue
-		}
-
-		switch fields[k].(type) {
+	for fk := range fields {
+		switch fields[fk].(type) {
 		case string:
-			delete(fields, k)
+			if p.stringFields != nil && p.stringFields.Match(fk) {
+				continue
+			}
+			delete(fields, fk)
 		case bool:
-			delete(fields, k)
+			delete(fields, fk)
 		}
 	}
 	return tags, fields
 }
 
-func (p *JSONParser) Parse(buf []byte) ([]telegraf.Metric, error) {
-	if p.JSONQuery != "" {
-		result := gjson.GetBytes(buf, p.JSONQuery)
+func (p *Parser) Parse(buf []byte) ([]telegraf.Metric, error) {
+	if p.query != "" {
+		result := gjson.GetBytes(buf, p.query)
 		buf = []byte(result.Raw)
 		if !result.IsArray() && !result.IsObject() {
 			err := fmt.Errorf("E! Query path must lead to a JSON object or array of objects, but lead to: %v", result.Type)
@@ -181,7 +206,7 @@ func (p *JSONParser) Parse(buf []byte) ([]telegraf.Metric, error) {
 	return p.parseArray(buf)
 }
 
-func (p *JSONParser) ParseLine(line string) (telegraf.Metric, error) {
+func (p *Parser) ParseLine(line string) (telegraf.Metric, error) {
 	metrics, err := p.Parse([]byte(line + "\n"))
 
 	if err != nil {
@@ -195,8 +220,8 @@ func (p *JSONParser) ParseLine(line string) (telegraf.Metric, error) {
 	return metrics[0], nil
 }
 
-func (p *JSONParser) SetDefaultTags(tags map[string]string) {
-	p.DefaultTags = tags
+func (p *Parser) SetDefaultTags(tags map[string]string) {
+	p.defaultTags = tags
 }
 
 type JSONFlattener struct {