feat: Migrate form_urlencoded parser to new style

config/config.go

@@ -1764,7 +1764,6 @@ func (c *Config) missingTomlField(_ reflect.Type, key string) error {
 		// "templates", // shared with serializers
 		"dropwizard_metric_registry_path", "dropwizard_tags_path", "dropwizard_tag_paths",
 		"dropwizard_time_format", "dropwizard_time_path",
-		"form_urlencoded_tag_keys",
 		"grok_custom_pattern_files", "grok_custom_patterns", "grok_named_patterns", "grok_patterns",
 		"grok_timezone", "grok_unique_timestamp",
 		"influx_parser_type",

plugins/inputs/http_listener_v2/http_listener_v2_test.go

@@ -18,6 +18,7 @@ import (
 
 	"github.com/influxdata/telegraf/config"
 	"github.com/influxdata/telegraf/plugins/parsers"
+	"github.com/influxdata/telegraf/plugins/parsers/form_urlencoded"
 	"github.com/influxdata/telegraf/testutil"
 )
 
@@ -592,10 +593,14 @@ func TestWriteHTTPTransformHeaderValuesToTagsBulkWrite(t *testing.T) {
 }
 
 func TestWriteHTTPQueryParams(t *testing.T) {
-	parser, _ := parsers.NewFormUrlencodedParser("query_measurement", nil, []string{"tagKey"})
+	parser := form_urlencoded.Parser{
+		MetricName: "query_measurement",
+		TagKeys:    []string{"tagKey"},
+	}
+
 	listener := newTestHTTPListenerV2()
 	listener.DataSource = "query"
-	listener.Parser = parser
+	listener.Parser = &parser
 
 	acc := &testutil.Accumulator{}
 	require.NoError(t, listener.Init())
@@ -615,9 +620,13 @@ func TestWriteHTTPQueryParams(t *testing.T) {
 }
 
 func TestWriteHTTPFormData(t *testing.T) {
-	parser, _ := parsers.NewFormUrlencodedParser("query_measurement", nil, []string{"tagKey"})
+	parser := form_urlencoded.Parser{
+		MetricName: "query_measurement",
+		TagKeys:    []string{"tagKey"},
+	}
+
 	listener := newTestHTTPListenerV2()
-	listener.Parser = parser
+	listener.Parser = &parser
 
 	acc := &testutil.Accumulator{}
 	require.NoError(t, listener.Init())

plugins/parsers/all/all.go

@@ -4,6 +4,7 @@ import (
 	//Blank imports for plugins to register themselves
 	_ "github.com/influxdata/telegraf/plugins/parsers/collectd"
 	_ "github.com/influxdata/telegraf/plugins/parsers/csv"
+	_ "github.com/influxdata/telegraf/plugins/parsers/form_urlencoded"
 	_ "github.com/influxdata/telegraf/plugins/parsers/json"
 	_ "github.com/influxdata/telegraf/plugins/parsers/json_v2"
 	_ "github.com/influxdata/telegraf/plugins/parsers/wavefront"

plugins/parsers/form_urlencoded/parser.go

@@ -9,19 +9,16 @@ import (
 
 	"github.com/influxdata/telegraf"
 	"github.com/influxdata/telegraf/metric"
+	"github.com/influxdata/telegraf/plugins/parsers"
 )
 
-var (
-	// ErrNoMetric is returned when no metric is found in input line
-	ErrNoMetric = fmt.Errorf("no metric in line")
-)
+var ErrNoMetric = fmt.Errorf("no metric in line")
 
 // Parser decodes "application/x-www-form-urlencoded" data into metrics
 type Parser struct {
-	MetricName  string
-	DefaultTags map[string]string
-	TagKeys     []string
-	AllowedKeys []string
+	MetricName  string            `toml:"-"`
+	TagKeys     []string          `toml:"form_urlencoded_tag_keys"`
+	DefaultTags map[string]string `toml:"-"`
 }
 
 // Parse converts a slice of bytes in "application/x-www-form-urlencoded" format into metrics
@@ -36,10 +33,6 @@ func (p Parser) Parse(buf []byte) ([]telegraf.Metric, error) {
 		return nil, err
 	}
 
-	if len(p.AllowedKeys) > 0 {
-		values = p.filterAllowedKeys(values)
-	}
-
 	tags := p.extractTags(values)
 	fields := p.parseFields(values)
 
@@ -71,21 +64,6 @@ func (p *Parser) SetDefaultTags(tags map[string]string) {
 	p.DefaultTags = tags
 }
 
-func (p Parser) filterAllowedKeys(original url.Values) url.Values {
-	result := make(url.Values)
-
-	for _, key := range p.AllowedKeys {
-		value, exists := original[key]
-		if !exists {
-			continue
-		}
-
-		result[key] = value
-	}
-
-	return result
-}
-
 func (p Parser) extractTags(values url.Values) map[string]string {
 	tags := make(map[string]string)
 	for _, key := range p.TagKeys {
@@ -120,3 +98,16 @@ func (p Parser) parseFields(values url.Values) map[string]interface{} {
 
 	return fields
 }
+
+func (p *Parser) InitFromConfig(config *parsers.Config) error {
+	p.MetricName = config.MetricName
+	p.TagKeys = config.FormUrlencodedTagKeys
+	return nil
+}
+
+func init() {
+	parsers.Add("form_urlencoded",
+		func(defaultMetricName string) telegraf.Parser {
+			return &Parser{MetricName: defaultMetricName}
+		})
+}

plugins/parsers/registry.go

@@ -5,7 +5,6 @@ import (
 
 	"github.com/influxdata/telegraf"
 	"github.com/influxdata/telegraf/plugins/parsers/dropwizard"
-	"github.com/influxdata/telegraf/plugins/parsers/form_urlencoded"
 	"github.com/influxdata/telegraf/plugins/parsers/graphite"
 	"github.com/influxdata/telegraf/plugins/parsers/grok"
 	"github.com/influxdata/telegraf/plugins/parsers/influx"
@@ -238,12 +237,6 @@ func NewParser(config *Config) (Parser, error) {
 			config.GrokUniqueTimestamp)
 	case "logfmt":
 		parser, err = NewLogFmtParser(config.MetricName, config.DefaultTags, config.LogFmtTagKeys)
-	case "form_urlencoded":
-		parser, err = NewFormUrlencodedParser(
-			config.MetricName,
-			config.DefaultTags,
-			config.FormUrlencodedTagKeys,
-		)
 	case "prometheus":
 		parser, err = NewPrometheusParser(
 			config.DefaultTags,
@@ -349,18 +342,6 @@ func NewLogFmtParser(metricName string, defaultTags map[string]string, tagKeys [
 	return parser, err
 }
 
-func NewFormUrlencodedParser(
-	metricName string,
-	defaultTags map[string]string,
-	tagKeys []string,
-) (Parser, error) {
-	return &form_urlencoded.Parser{
-		MetricName:  metricName,
-		DefaultTags: defaultTags,
-		TagKeys:     tagKeys,
-	}, nil
-}
-
 func NewPrometheusParser(defaultTags map[string]string, ignoreTimestamp bool) (Parser, error) {
 	return &prometheus.Parser{
 		DefaultTags:     defaultTags,