simplify elegant shutdown

go.mod

@@ -85,7 +85,6 @@ require (
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/ini.v1 v1.66.2 // indirect
 	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
-	honnef.co/go/netdb v0.0.0-20210921115105-e902e863d85d // indirect
 	k8s.io/klog/v2 v2.30.0 // indirect
 	k8s.io/kube-openapi v0.0.0-20211115234752-e816edb12b65 // indirect
 	k8s.io/utils v0.0.0-20211116205334-6203023598ed // indirect

go.sum

@@ -1523,8 +1523,6 @@ gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b/go.mod h1:K4uyk7z7BCEPqu6E+C
 gotest.tools v2.2.0+incompatible/go.mod h1:DsYFclhRJ6vuDpmuTbkuFWG+y2sxOXAzmJt81HFBacw=
 gotest.tools/v3 v3.0.2/go.mod h1:3SzNCllyD9/Y+b5r9JIKQ474KzkZyqLqEfYqMsX94Bk=
 gotest.tools/v3 v3.0.3/go.mod h1:Z7Lb0S5l+klDB31fvDQX8ss/FlKDxtlFlw3Oa8Ymbl8=
-honnef.co/go/netdb v0.0.0-20210921115105-e902e863d85d h1:yjDpoTxoYVpCt04OYp8zlZsKtrEOK1O4U7l2aWbn3D8=
-honnef.co/go/netdb v0.0.0-20210921115105-e902e863d85d/go.mod h1:rbNo0ST5hSazCG4rGfpHrwnwvzP1QX62WbhzD+ghGzs=
 honnef.co/go/tools v0.0.0-20180728063816-88497007e858/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190106161140-3f1c8253044a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=

pkg/pipeline/encode/encode_prom.go

@@ -82,7 +82,7 @@ type encodeProm struct {
 	expiryTime int64
 	mList      *list.List
 	mCache     metricCache
-	exitChan   chan struct{}
+	exitChan   <-chan struct{}
 }
 
 var metricsProcessed = operationalMetrics.NewCounter(prometheus.CounterOpts{
@@ -336,9 +336,6 @@ func NewEncodeProm(params config.StageParam) (Encoder, error) {
 		}
 	}
 
-	ch := make(chan struct{})
-	utils.RegisterExitChannel(ch)
-
 	log.Debugf("metrics = %v", metrics)
 	w := &encodeProm{
 		port:       fmt.Sprintf(":%v", portNum),
@@ -347,7 +344,7 @@ func NewEncodeProm(params config.StageParam) (Encoder, error) {
 		expiryTime: expiryTime,
 		mList:      list.New(),
 		mCache:     make(metricCache),
-		exitChan:   ch,
+		exitChan:   utils.ExitChannel(),
 	}
 	go startPrometheusInterface(w)
 	go w.cleanupExpiredEntriesLoop()

pkg/pipeline/extract/aggregate/aggregates.go

@@ -75,12 +75,10 @@ func (aggregates *Aggregates) AddAggregate(aggregateDefinition api.AggregateDefi
 func (aggregates *Aggregates) cleanupExpiredEntriesLoop() {
 
 	ticker := time.NewTicker(time.Duration(aggregates.expiryTime) * time.Second)
-	done := make(chan struct{})
-	utils.RegisterExitChannel(done)
 	go func() {
 		for {
 			select {
-			case <-done:
+			case <-utils.ExitChannel():
 				return
 			case <-ticker.C:
 				aggregates.cleanupExpiredEntries()

pkg/pipeline/ingest/ingest_collector.go

@@ -51,7 +51,7 @@ type ingestCollector struct {
 	in             chan map[string]interface{}
 	batchFlushTime time.Duration
 	batchMaxLength int
-	exitChan       chan struct{}
+	exitChan       <-chan struct{}
 }
 
 // TransportWrapper is an implementation of the goflow2 transport interface
@@ -200,9 +200,6 @@ func NewIngestCollector(params config.StageParam) (Ingester, error) {
 	log.Infof("hostname = %s", jsonIngestCollector.HostName)
 	log.Infof("port = %d", jsonIngestCollector.Port)
 
-	ch := make(chan struct{})
-	pUtils.RegisterExitChannel(ch)
-
 	bml := defaultBatchMaxLength
 	if jsonIngestCollector.BatchMaxLen != 0 {
 		bml = jsonIngestCollector.BatchMaxLen
@@ -211,7 +208,7 @@ func NewIngestCollector(params config.StageParam) (Ingester, error) {
 	return &ingestCollector{
 		hostname:       jsonIngestCollector.HostName,
 		port:           jsonIngestCollector.Port,
-		exitChan:       ch,
+		exitChan:       pUtils.ExitChannel(),
 		batchFlushTime: defaultBatchFlushTime,
 		batchMaxLength: bml,
 	}, nil

pkg/pipeline/ingest/ingest_file.go

@@ -30,7 +30,7 @@ import (
 
 type IngestFile struct {
 	params       config.Ingest
-	exitChan     chan struct{}
+	exitChan     <-chan struct{}
 	PrevRecords  []interface{}
 	TotalRecords int
 }
@@ -104,10 +104,8 @@ func NewIngestFile(params config.StageParam) (Ingester, error) {
 
 	log.Debugf("input file name = %s", params.Ingest.File.Filename)
 
-	ch := make(chan struct{})
-	utils.RegisterExitChannel(ch)
 	return &IngestFile{
 		params:   params.Ingest,
-		exitChan: ch,
+		exitChan: utils.ExitChannel(),
 	}, nil
 }

pkg/pipeline/ingest/ingest_grpc.go

@@ -38,10 +38,8 @@ func NewGRPCProtobuf(params config.StageParam) (*GRPCProtobuf, error) {
 }
 
 func (no *GRPCProtobuf) Ingest(out chan<- []interface{}) {
-	exitCh := make(chan struct{})
-	utils.RegisterExitChannel(exitCh)
 	go func() {
-		<-exitCh
+		<-utils.ExitChannel()
 		close(no.flowPackets)
 		no.collector.Close()
 	}()

pkg/pipeline/ingest/ingest_kafka.go

@@ -38,7 +38,7 @@ type ingestKafka struct {
 	kafkaParams api.IngestKafka
 	kafkaReader kafkaReadMessage
 	in          chan string
-	exitChan    chan struct{}
+	exitChan    <-chan struct{}
 	prevRecords []interface{} // copy of most recently sent records; for testing and debugging
 }
 
@@ -153,13 +153,10 @@ func NewIngestKafka(params config.StageParam) (Ingester, error) {
 	}
 	log.Debugf("kafkaReader = %v", kafkaReader)
 
-	ch := make(chan struct{})
-	utils.RegisterExitChannel(ch)
-
 	return &ingestKafka{
 		kafkaParams: jsonIngestKafka,
 		kafkaReader: kafkaReader,
-		exitChan:    ch,
+		exitChan:    utils.ExitChannel(),
 		in:          make(chan string, channelSizeKafka),
 		prevRecords: make([]interface{}, 0),
 	}, nil

pkg/pipeline/ingest/ingest_kafka_test.go

@@ -124,10 +124,6 @@ func Test_IngestKafka(t *testing.T) {
 	require.Equal(t, record1, receivedEntries[0])
 	require.Equal(t, record2, receivedEntries[1])
 	require.Equal(t, record3, receivedEntries[2])
-
-	// make the ingest thread exit
-	close(ingestKafka.exitChan)
-	time.Sleep(time.Second)
 }
 
 type fakeKafkaReader struct {
@@ -177,9 +173,4 @@ func Test_KafkaListener(t *testing.T) {
 
 	require.Equal(t, 1, len(receivedEntries))
 	require.Equal(t, string(fakeRecord), receivedEntries[0])
-
-	// make the ingest thread exit
-	close(ingestKafka.exitChan)
-	time.Sleep(time.Second)
-
 }

pkg/pipeline/utils/exit.go

@@ -20,40 +20,31 @@ package utils
 import (
 	"os"
 	"os/signal"
-	"sync"
 	"syscall"
 
 	log "github.com/sirupsen/logrus"
 )
 
 var (
-	registeredChannels []chan struct{}
-	chanMutex          sync.Mutex
+	exitChannel chan struct{}
 )
 
-func RegisterExitChannel(ch chan struct{}) {
-	chanMutex.Lock()
-	defer chanMutex.Unlock()
-	registeredChannels = append(registeredChannels, ch)
+func ExitChannel() <-chan struct{} {
+	return exitChannel
 }
 
 func SetupElegantExit() {
 	log.Debugf("entering SetupElegantExit")
 	// handle elegant exit; create support for channels of go routines that want to exit cleanly
-	registeredChannels = make([]chan struct{}, 0)
+	exitChannel = make(chan struct{})
 	exitSigChan := make(chan os.Signal, 1)
 	log.Debugf("registered exit signal channel")
 	signal.Notify(exitSigChan, syscall.SIGINT, syscall.SIGTERM)
 	go func() {
 		// wait for exit signal; then stop all the other go functions
 		sig := <-exitSigChan
 		log.Debugf("received exit signal = %v", sig)
-		chanMutex.Lock()
-		defer chanMutex.Unlock()
-		// exit signal received; stop other go functions
-		for _, ch := range registeredChannels {
-			close(ch)
-		}
+		close(exitChannel)
 		log.Debugf("exiting SetupElegantExit go function")
 	}()
 	log.Debugf("exiting SetupElegantExit")

pkg/pipeline/utils/exit_test.go

@@ -10,19 +10,9 @@ import (
 
 func Test_SetupElegantExit(t *testing.T) {
 	SetupElegantExit()
-	require.Equal(t, 0, len(registeredChannels))
-	ch1 := make(chan struct{})
-	ch2 := make(chan struct{})
-	ch3 := make(chan struct{})
-	RegisterExitChannel(ch1)
-	require.Equal(t, 1, len(registeredChannels))
-	RegisterExitChannel(ch2)
-	require.Equal(t, 2, len(registeredChannels))
-	RegisterExitChannel(ch3)
-	require.Equal(t, 3, len(registeredChannels))
 
 	select {
-	case <-ch1:
+	case <-ExitChannel():
 		// should not get here
 		require.Error(t, fmt.Errorf("channel should have been empty"))
 	default:
@@ -34,7 +24,7 @@ func Test_SetupElegantExit(t *testing.T) {
 	require.Equal(t, nil, err)
 
 	select {
-	case <-ch1:
+	case <-ExitChannel():
 		break
 	default:
 		// should not get here

pkg/pipeline/write/write_loki.go

@@ -56,7 +56,7 @@ type Loki struct {
 	client     emitter
 	timeNow    func() time.Time
 	in         chan config.GenericMap
-	exitChan   chan struct{}
+	exitChan   <-chan struct{}
 }
 
 var recordsWritten = operationalMetrics.NewCounter(prometheus.CounterOpts{
@@ -263,17 +263,14 @@ func NewWriteLoki(params config.StageParam) (*Loki, error) {
 		return nil, err
 	}
 
-	ch := make(chan struct{})
-	pUtils.RegisterExitChannel(ch)
-
 	in := make(chan config.GenericMap, channelSize)
 
 	l := &Loki{
 		lokiConfig: lokiConfig,
 		apiConfig:  jsonWriteLoki,
 		client:     client,
 		timeNow:    time.Now,
-		exitChan:   ch,
+		exitChan:   pUtils.ExitChannel(),
 		in:         in,
 	}