calling fetchAndSaveCounts in the scaler after any interceptor deployment events

scaler/config.go

@@ -18,6 +18,8 @@ type config struct {
 	TargetNamespace string `envconfig:"KEDA_HTTP_SCALER_TARGET_ADMIN_NAMESPACE" required:"true"`
 	// TargetService is the name of the service to issue metrics RPC requests to interceptors
 	TargetService string `envconfig:"KEDA_HTTP_SCALER_TARGET_ADMIN_SERVICE" required:"true"`
+	// TargetDeployment is the name of the deployment to issue metrics RPC requests to interceptors
+	TargetDeployment string `envconfig:"KEDA_HTTP_SCALER_TARGET_ADMIN_DEPLOYMENT" required:"true"`
 	// TargetPort is the port on TargetService to which to issue metrics RPC requests to
 	// interceptors
 	TargetPort int `envconfig:"KEDA_HTTP_SCALER_TARGET_ADMIN_PORT" required:"true"`
@@ -29,6 +31,9 @@ type config struct {
 	// ConfigMapCacheRsyncPeriod is the time interval
 	// for the configmap informer to rsync the local cache.
 	ConfigMapCacheRsyncPeriod time.Duration `envconfig:"KEDA_HTTP_SCALER_CONFIG_MAP_INFORMER_RSYNC_PERIOD" default:"60m"`
+	// DeploymentCacheRsyncPeriod is the time interval
+	// for the deployment informer to rsync the local cache.
+	DeploymentCacheRsyncPeriod time.Duration `envconfig:"KEDA_HTTP_SCALER_DEPLOYMENT_INFORMER_RSYNC_PERIOD" default:"60m"`
 	// QueueTickDuration is the duration between queue requests
 	QueueTickDuration time.Duration `envconfig:"KEDA_HTTP_QUEUE_TICK_DURATION" default:"500ms"`
 	// This will be the 'Target Pending Requests' for the interceptor

scaler/main.go

@@ -39,6 +39,7 @@ func main() {
 	healthPort := cfg.HealthPort
 	namespace := cfg.TargetNamespace
 	svcName := cfg.TargetService
+	deplName := cfg.TargetDeployment
 	targetPortStr := fmt.Sprintf("%d", cfg.TargetPort)
 	targetPendingRequests := cfg.TargetPendingRequests
 	targetPendingRequestsInterceptor := cfg.TargetPendingRequestsInterceptor
@@ -54,6 +55,7 @@ func main() {
 		k8s.EndpointsFuncForK8sClientset(k8sCl),
 		namespace,
 		svcName,
+		deplName,
 		targetPortStr,
 	)
 	if err != nil {
@@ -81,14 +83,27 @@ func main() {
 		k8sCl,
 		cfg.ConfigMapCacheRsyncPeriod,
 	)
+	// create the deployment informer
+	deployInformer := k8s.NewInformerBackedDeploymentCache(
+		lggr,
+		k8sCl,
+		cfg.DeploymentCacheRsyncPeriod,
+	)
 
 	grp, ctx := errgroup.WithContext(ctx)
 
+	// start the deployment informer
+	grp.Go(func() error {
+		defer done()
+		return deployInformer.Start(ctx)
+	})
+
 	grp.Go(func() error {
 		defer done()
 		return pinger.start(
 			ctx,
 			time.NewTicker(cfg.QueueTickDuration),
+			deployInformer,
 		)
 	})
 

scaler/queue_pinger.go

@@ -34,15 +34,16 @@ import (
 //	go pinger.start(ctx, ticker)
 //
 type queuePinger struct {
-	getEndpointsFn     k8s.GetEndpointsFunc
-	interceptorNS      string
-	interceptorSvcName string
-	adminPort          string
-	pingMut            *sync.RWMutex
-	lastPingTime       time.Time
-	allCounts          map[string]int
-	aggregateCount     int
-	lggr               logr.Logger
+	getEndpointsFn      k8s.GetEndpointsFunc
+	interceptorNS       string
+	interceptorSvcName  string
+	interceptorDeplName string
+	adminPort           string
+	pingMut             *sync.RWMutex
+	lastPingTime        time.Time
+	allCounts           map[string]int
+	aggregateCount      int
+	lggr                logr.Logger
 }
 
 func newQueuePinger(
@@ -51,18 +52,20 @@ func newQueuePinger(
 	getEndpointsFn k8s.GetEndpointsFunc,
 	ns,
 	svcName,
+	deplName,
 	adminPort string,
 ) (*queuePinger, error) {
 	pingMut := new(sync.RWMutex)
 	pinger := &queuePinger{
-		getEndpointsFn:     getEndpointsFn,
-		interceptorNS:      ns,
-		interceptorSvcName: svcName,
-		adminPort:          adminPort,
-		pingMut:            pingMut,
-		lggr:               lggr,
-		allCounts:          map[string]int{},
-		aggregateCount:     0,
+		getEndpointsFn:      getEndpointsFn,
+		interceptorNS:       ns,
+		interceptorSvcName:  svcName,
+		interceptorDeplName: deplName,
+		adminPort:           adminPort,
+		pingMut:             pingMut,
+		lggr:                lggr,
+		allCounts:           map[string]int{},
+		aggregateCount:      0,
 	}
 	return pinger, pinger.fetchAndSaveCounts(ctx)
 }
@@ -71,11 +74,17 @@ func newQueuePinger(
 func (q *queuePinger) start(
 	ctx context.Context,
 	ticker *time.Ticker,
+	deplCache k8s.DeploymentCache,
 ) error {
+	deployWatchIface := deplCache.Watch(q.interceptorNS, q.interceptorDeplName)
+	deployEvtChan := deployWatchIface.ResultChan()
+	defer deployWatchIface.Stop()
+
 	lggr := q.lggr.WithName("scaler.queuePinger.start")
 	defer ticker.Stop()
-	for range ticker.C {
+	for {
 		select {
+		// handle cancellations/timeout
 		case <-ctx.Done():
 			lggr.Error(
 				ctx.Err(),
@@ -85,7 +94,8 @@ func (q *queuePinger) start(
 				ctx.Err(),
 				"context marked done. stopping queuePinger loop",
 			)
-		default:
+		// do our regularly scheduled work
+		case <-ticker.C:
 			err := q.fetchAndSaveCounts(ctx)
 			if err != nil {
 				lggr.Error(err, "getting request counts")
@@ -94,9 +104,18 @@ func (q *queuePinger) start(
 					"error getting request counts",
 				)
 			}
+		// handle changes to the interceptor fleet
+		// Deployment
+		case <-deployEvtChan:
+			err := q.fetchAndSaveCounts(ctx)
+			if err != nil {
+				lggr.Error(
+					err,
+					"getting request counts after interceptor deployment event",
+				)
+			}
 		}
 	}
-	return nil
 }
 
 func (q *queuePinger) counts() map[string]int {

scaler/queue_pinger_fake.go

@@ -77,6 +77,7 @@ func newFakeQueuePinger(
 		},
 		"testns",
 		"testsvc",
+		"testdepl",
 		opts.port,
 	)
 	if err != nil {

scaler/queue_pinger_test.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/go-logr/logr"
+	"github.com/kedacore/http-add-on/pkg/k8s"
 	"github.com/kedacore/http-add-on/pkg/queue"
 	"github.com/stretchr/testify/require"
 	v1 "k8s.io/api/core/v1"
@@ -17,6 +18,7 @@ func TestCounts(t *testing.T) {
 	const (
 		ns           = "testns"
 		svcName      = "testsvc"
+		deplName     = "testdepl"
 		tickDur      = 10 * time.Millisecond
 		numEndpoints = 3
 	)
@@ -51,6 +53,7 @@ func TestCounts(t *testing.T) {
 		},
 		ns,
 		svcName,
+		deplName,
 		srvURL.Port(),
 	)
 	r.NoError(err)
@@ -66,8 +69,9 @@ func TestCounts(t *testing.T) {
 	q.Resize("host3", 3)
 	q.Resize("host4", 4)
 	ticker := time.NewTicker(tickDur)
+	fakeCache := k8s.NewFakeDeploymentCache()
 	go func() {
-		pinger.start(ctx, ticker)
+		pinger.start(ctx, ticker, fakeCache)
 	}()
 	// sleep to ensure we ticked and finished calling
 	// fetchAndSaveCounts
@@ -100,6 +104,7 @@ func TestFetchAndSaveCounts(t *testing.T) {
 	const (
 		ns           = "testns"
 		svcName      = "testsvc"
+		deplName     = "testdepl"
 		adminPort    = "8081"
 		numEndpoints = 3
 	)
@@ -132,6 +137,7 @@ func TestFetchAndSaveCounts(t *testing.T) {
 		endpointsFn,
 		ns,
 		svcName,
+		deplName,
 		srvURL.Port(),
 		// time.NewTicker(1*time.Millisecond),
 	)