user pkg drain for draining in queue proxy

cmd/queue/main.go

@@ -177,11 +177,11 @@ func main() {
 		probe = buildProbe(logger, env.ServingReadinessProbe, env.EnableHTTP2AutoDetection).ProbeContainer
 	}
 
-	healthState := health.NewState()
+	healthState := health.NewState(drainSleepDuration)
 	mainServer := buildServer(ctx, env, healthState, probe, stats, logger)
 	servers := map[string]*http.Server{
 		"main":    mainServer,
-		"admin":   buildAdminServer(logger, healthState),
+		"admin":   buildAdminServer(healthState),
 		"metrics": buildMetricsServer(promStatReporter, protoStatReporter),
 	}
 	if env.EnableProfiling {
@@ -242,7 +242,7 @@ func main() {
 		logger.Info("Received TERM signal, attempting to gracefully shutdown servers.")
 		healthState.Shutdown(func() {
 			logger.Infof("Sleeping %v to allow K8s propagation of non-ready state", drainSleepDuration)
-			time.Sleep(drainSleepDuration)
+			healthState.Drainer.Drain()
 
 			// Calling server.Shutdown() allows pending requests to
 			// complete, while no new work is accepted.
@@ -388,17 +388,10 @@ func supportsMetrics(ctx context.Context, logger *zap.SugaredLogger, env config)
 	return true
 }
 
-func buildAdminServer(logger *zap.SugaredLogger, healthState *health.State) *http.Server {
-	adminMux := http.NewServeMux()
-	drainHandler := healthState.DrainHandlerFunc()
-	adminMux.HandleFunc(queue.RequestQueueDrainPath, func(w http.ResponseWriter, r *http.Request) {
-		logger.Info("Attached drain handler from user-container")
-		drainHandler(w, r)
-	})
-
+func buildAdminServer(healthState *health.State) *http.Server {
 	return &http.Server{
 		Addr:    ":" + strconv.Itoa(networking.QueueAdminPort),
-		Handler: adminMux,
+		Handler: healthState.Drainer,
 	}
 }
 

pkg/queue/health/health_state.go

@@ -20,7 +20,9 @@ import (
 	"io"
 	"net/http"
 	"sync"
+	"time"
 
+	"knative.dev/pkg/network/handlers"
 	"knative.dev/serving/pkg/queue"
 )
 
@@ -30,15 +32,29 @@ type State struct {
 	shuttingDown bool
 	mutex        sync.RWMutex
 
+	Drainer        *handlers.Drainer
 	drainCh        chan struct{}
 	drainCompleted bool
 }
 
 // NewState returns a new State with both alive and shuttingDown set to false.
-func NewState() *State {
-	return &State{
+// drainSleepDuration configures the QuietPeriod for the Drainer.
+func NewState(drainSleepDuration time.Duration) *State {
+	state := &State{
 		drainCh: make(chan struct{}),
 	}
+
+	adminMux := http.NewServeMux()
+	adminMux.HandleFunc(queue.RequestQueueDrainPath, func(w http.ResponseWriter, r *http.Request) {
+		state.DrainHandlerFunc()
+	})
+
+	state.Drainer = &handlers.Drainer{
+		Inner:       adminMux,
+		QuietPeriod: drainSleepDuration,
+	}
+
+	return state
 }
 
 // isAlive returns whether or not the health server is in a known

pkg/queue/health/health_state_test.go

@@ -25,8 +25,10 @@ import (
 	"knative.dev/serving/pkg/queue"
 )
 
+const testDrainSleepDuration = 1 * time.Second
+
 func TestHealthStateSetsState(t *testing.T) {
-	s := NewState()
+	s := NewState(testDrainSleepDuration)
 
 	wantAlive := func() {
 		if !s.isAlive() {
@@ -123,7 +125,7 @@ func TestHealthStateHealthHandler(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			state := NewState()
+			state := NewState(testDrainSleepDuration)
 			state.alive = test.alive
 			state.shuttingDown = test.shuttingDown
 
@@ -142,7 +144,7 @@ func TestHealthStateHealthHandler(t *testing.T) {
 }
 
 func TestHealthStateDrainHandler(t *testing.T) {
-	state := NewState()
+	state := NewState(testDrainSleepDuration)
 	state.setAlive()
 
 	req := httptest.NewRequest(http.MethodGet, "/", nil)
@@ -165,7 +167,7 @@ func TestHealthStateDrainHandler(t *testing.T) {
 }
 
 func TestHealthStateDrainHandlerNotRacy(t *testing.T) {
-	state := NewState()
+	state := NewState(testDrainSleepDuration)
 	state.setAlive()
 
 	// Complete the drain _before_ the DrainHandlerFunc is attached.
@@ -194,7 +196,7 @@ func TestHealthStateDrainHandlerNotRacy(t *testing.T) {
 }
 
 func TestHealthStateShutdown(t *testing.T) {
-	state := NewState()
+	state := NewState(testDrainSleepDuration)
 	state.setAlive()
 
 	calledCh := make(chan struct{}, 1)