filebeat/input/udp: convert to v2 input (#33930)

Co-authored-by: Andrew Kroh <[email protected]>

CHANGELOG.next.asciidoc

@@ -168,6 +168,7 @@ https://github.com/elastic/beats/compare/v8.2.0\...main[Check the HEAD diff]
 - Add support for http+unix and http+npipe schemes in cel input. {issue}33571[33571] {pull}33712[33712]
 - Add `decode_duration`, `move_fields` processors. {pull}31301[31301]
 - Add metrics for UDP packet processing. {pull}33870[33870]
+- Convert UDP input to v2 input. {pull}33930[33930]
 
 *Auditbeat*
 

filebeat/input/default-inputs/inputs.go

@@ -21,6 +21,7 @@ import (
 	"github.com/elastic/beats/v7/filebeat/beater"
 	"github.com/elastic/beats/v7/filebeat/input/filestream"
 	"github.com/elastic/beats/v7/filebeat/input/kafka"
+	"github.com/elastic/beats/v7/filebeat/input/udp"
 	"github.com/elastic/beats/v7/filebeat/input/unix"
 	v2 "github.com/elastic/beats/v7/filebeat/input/v2"
 	"github.com/elastic/beats/v7/libbeat/beat"
@@ -38,6 +39,7 @@ func genericInputs(log *logp.Logger, components beater.StateStore) []v2.Plugin {
 	return []v2.Plugin{
 		filestream.Plugin(log, components),
 		kafka.Plugin(),
+		udp.Plugin(),
 		unix.Plugin(),
 	}
 }

filebeat/input/udp/input.go

@@ -18,63 +18,88 @@
 package udp
 
 import (
-	"fmt"
-	"sync"
+	"net"
 	"time"
 
-	"github.com/mitchellh/hashstructure"
+	"github.com/dustin/go-humanize"
 	"github.com/rcrowley/go-metrics"
 
-	"github.com/elastic/beats/v7/filebeat/channel"
-	"github.com/elastic/beats/v7/filebeat/harvester"
-	"github.com/elastic/beats/v7/filebeat/input"
+	input "github.com/elastic/beats/v7/filebeat/input/v2"
+	stateless "github.com/elastic/beats/v7/filebeat/input/v2/input-stateless"
 	"github.com/elastic/beats/v7/filebeat/inputsource"
 	"github.com/elastic/beats/v7/filebeat/inputsource/udp"
 	"github.com/elastic/beats/v7/libbeat/beat"
+	"github.com/elastic/beats/v7/libbeat/feature"
 	"github.com/elastic/beats/v7/libbeat/monitoring/inputmon"
 	conf "github.com/elastic/elastic-agent-libs/config"
-	"github.com/elastic/elastic-agent-libs/logp"
 	"github.com/elastic/elastic-agent-libs/mapstr"
 	"github.com/elastic/elastic-agent-libs/monitoring"
 	"github.com/elastic/elastic-agent-libs/monitoring/adapter"
+	"github.com/elastic/go-concert/ctxtool"
 )
 
-func init() {
-	err := input.Register("udp", NewInput)
-	if err != nil {
-		panic(err)
+func Plugin() input.Plugin {
+	return input.Plugin{
+		Name:       "udp",
+		Stability:  feature.Stable,
+		Deprecated: false,
+		Info:       "udp packet server",
+		Manager:    stateless.NewInputManager(configure),
 	}
 }
 
-// Input defines a udp input to receive event on a specific host:port.
-type Input struct {
-	sync.Mutex
-	udp     *udp.Server
-	started bool
-	outlet  channel.Outleter
+func configure(cfg *conf.C) (stateless.Input, error) {
+	config := defaultConfig()
+	if err := cfg.Unpack(&config); err != nil {
+		return nil, err
+	}
 
-	metrics *inputMetrics
+	return newServer(config)
 }
 
-// NewInput creates a new udp input
-func NewInput(cfg *conf.C, outlet channel.Connector, context input.Context) (input.Input, error) {
-	id, err := configID(cfg)
-	if err != nil {
-		return nil, err
+func defaultConfig() config {
+	return config{
+		Config: udp.Config{
+			MaxMessageSize: 10 * humanize.KiByte,
+			Host:           "localhost:8080",
+			Timeout:        time.Minute * 5,
+		},
 	}
-	out, err := outlet.Connect(cfg)
+}
+
+type server struct {
+	udp.Server
+	config
+}
+
+type config struct {
+	udp.Config `config:",inline"`
+}
+
+func newServer(config config) (*server, error) {
+	return &server{config: config}, nil
+}
+
+func (s *server) Name() string { return "udp" }
+
+func (s *server) Test(_ input.TestContext) error {
+	l, err := net.Listen("udp", s.config.Config.Host)
 	if err != nil {
-		return nil, err
+		return err
 	}
+	return l.Close()
+}
 
-	config := defaultConfig
-	if err = cfg.Unpack(&config); err != nil {
-		return nil, err
-	}
+func (s *server) Run(ctx input.Context, publisher stateless.Publisher) error {
+	log := ctx.Logger.With("host", s.config.Config.Host)
+
+	log.Info("starting udp socket input")
+	defer log.Info("udp input stopped")
+
+	metrics := newInputMetrics(ctx.ID, s.config.Host, uint64(s.config.ReadBuffer))
+	defer metrics.close()
 
-	forwarder := harvester.NewForwarder(out)
-	metrics := newInputMetrics(id, config.Host, uint64(config.ReadBuffer))
-	callback := func(data []byte, metadata inputsource.NetworkMetadata) {
+	server := udp.New(&s.config.Config, func(data []byte, metadata inputsource.NetworkMetadata) {
 		evt := beat.Event{
 			Timestamp: time.Now(),
 			Meta: mapstr.M{
@@ -91,74 +116,22 @@ func NewInput(cfg *conf.C, outlet channel.Connector, context input.Context) (inp
 				},
 			}
 		}
-		_ = forwarder.Send(evt)
+
+		publisher.Publish(evt)
 
 		// This must be called after forwarder.Send to measure
 		// the processing time metric.
 		metrics.log(data, evt.Timestamp)
-	}
-
-	udp := udp.New(&config.Config, callback)
-
-	return &Input{
-		outlet:  out,
-		udp:     udp,
-		started: false,
-		metrics: metrics,
-	}, nil
-}
-
-func configID(config *conf.C) (string, error) {
-	var tmp struct {
-		ID string `config:"id"`
-	}
-	if err := config.Unpack(&tmp); err != nil {
-		return "", fmt.Errorf("error extracting ID: %w", err)
-	}
-	if tmp.ID != "" {
-		return tmp.ID, nil
-	}
-
-	var h map[string]interface{}
-	_ = config.Unpack(&h)
-	id, err := hashstructure.Hash(h, nil)
-	if err != nil {
-		return "", fmt.Errorf("can not compute ID from configuration: %w", err)
-	}
+	})
 
-	return fmt.Sprintf("%16X", id), nil
-}
+	log.Debug("udp input initialized")
 
-// Run starts and start the UDP server and read events from the socket
-func (p *Input) Run() {
-	p.Lock()
-	defer p.Unlock()
-
-	if !p.started {
-		logp.Info("Starting UDP input")
-		err := p.udp.Start()
-		if err != nil {
-			logp.Err("Error running harvester: %v", err)
-		}
-		p.started = true
+	err := server.Run(ctxtool.FromCanceller(ctx.Cancelation))
+	// Ignore error from 'Run' in case shutdown was signaled.
+	if ctxerr := ctx.Cancelation.Err(); ctxerr != nil {
+		err = ctxerr
 	}
-}
-
-// Stop stops the UDP input
-func (p *Input) Stop() {
-	defer p.outlet.Close()
-	p.Lock()
-	defer p.Unlock()
-
-	logp.Info("Stopping UDP input")
-	p.udp.Stop()
-	p.metrics.close()
-	p.started = false
-}
-
-// Wait suspends the UDP input
-func (p *Input) Wait() {
-	p.Stop()
+	return err
 }
 
 // inputMetrics handles the input's metric reporting.