Merge pull request #103432 from p0lyn0mial/lifecycle_events

simply renames terminationSignals to lifecycleSignals

staging/src/k8s.io/apiserver/pkg/server/config.go

@@ -225,10 +225,10 @@ type Config struct {
 	// RequestWidthEstimator is used to estimate the "width" of the incoming request(s).
 	RequestWidthEstimator flowcontrolrequest.WidthEstimatorFunc
 
-	// terminationSignals provides access to the various shutdown signals
-	// that happen during the graceful termination of the apiserver.
+	// lifecycleSignals provides access to the various signals
+	// that happen during lifecycle of the apiserver.
 	// it's intentionally marked private as it should never be overridden.
-	terminationSignals terminationSignals
+	lifecycleSignals lifecycleSignals
 
 	//===========================================================================
 	// values below here are targets for removal
@@ -354,7 +354,7 @@ func NewConfig(codecs serializer.CodecFactory) *Config {
 		// Generic API servers have no inherent long-running subresources
 		LongRunningFunc:       genericfilters.BasicLongRunningRequestCheck(sets.NewString("watch"), sets.NewString()),
 		RequestWidthEstimator: flowcontrolrequest.DefaultWidthEstimator,
-		terminationSignals:    newTerminationSignals(),
+		lifecycleSignals:      newLifecycleSignals(),
 
 		APIServerID:           id,
 		StorageVersionManager: storageversion.NewDefaultManager(),
@@ -608,7 +608,7 @@ func (c completedConfig) New(name string, delegationTarget DelegationTarget) (*G
 		maxRequestBodyBytes: c.MaxRequestBodyBytes,
 		livezClock:          clock.RealClock{},
 
-		terminationSignals: c.terminationSignals,
+		lifecycleSignals: c.lifecycleSignals,
 
 		APIServerID:           c.APIServerID,
 		StorageVersionManager: c.StorageVersionManager,

staging/src/k8s.io/apiserver/pkg/server/genericapiserver.go

@@ -211,9 +211,8 @@ type GenericAPIServer struct {
 	// Version will enable the /version endpoint if non-nil
 	Version *version.Info
 
-	// terminationSignals provides access to the various termination
-	// signals that happen during the shutdown period of the apiserver.
-	terminationSignals terminationSignals
+	// lifecycleSignals provides access to the various signals that happen during the life cycle of the apiserver.
+	lifecycleSignals lifecycleSignals
 }
 
 // DelegationTarget is an interface which allows for composition of API servers with top level handling that works
@@ -310,7 +309,7 @@ func (s *GenericAPIServer) PrepareRun() preparedGenericAPIServer {
 	s.installLivez()
 
 	// as soon as shutdown is initiated, readiness should start failing
-	readinessStopCh := s.terminationSignals.ShutdownInitiated.Signaled()
+	readinessStopCh := s.lifecycleSignals.ShutdownInitiated.Signaled()
 	err := s.addReadyzShutdownCheck(readinessStopCh)
 	if err != nil {
 		klog.Errorf("Failed to install readyz shutdown check %s", err)
@@ -334,11 +333,12 @@ func (s *GenericAPIServer) PrepareRun() preparedGenericAPIServer {
 // Run spawns the secure http server. It only returns if stopCh is closed
 // or the secure port cannot be listened on initially.
 func (s preparedGenericAPIServer) Run(stopCh <-chan struct{}) error {
-	delayedStopCh := s.terminationSignals.AfterShutdownDelayDuration
-	shutdownInitiatedCh := s.terminationSignals.ShutdownInitiated
+	delayedStopCh := s.lifecycleSignals.AfterShutdownDelayDuration
+	shutdownInitiatedCh := s.lifecycleSignals.ShutdownInitiated
 
 	go func() {
 		defer delayedStopCh.Signal()
+		defer klog.V(1).InfoS("[graceful-termination] shutdown event", "name", delayedStopCh.Name())
 
 		<-stopCh
 
@@ -346,6 +346,7 @@ func (s preparedGenericAPIServer) Run(stopCh <-chan struct{}) error {
 		// This gives the load balancer a window defined by ShutdownDelayDuration to detect that /readyz is red
 		// and stop sending traffic to this server.
 		shutdownInitiatedCh.Signal()
+		klog.V(1).InfoS("[graceful-termination] shutdown event", "name", shutdownInitiatedCh.Name())
 
 		time.Sleep(s.ShutdownDelayDuration)
 	}()
@@ -355,15 +356,17 @@ func (s preparedGenericAPIServer) Run(stopCh <-chan struct{}) error {
 	if err != nil {
 		return err
 	}
-	httpServerStoppedListeningCh := s.terminationSignals.HTTPServerStoppedListening
+	httpServerStoppedListeningCh := s.lifecycleSignals.HTTPServerStoppedListening
 	go func() {
 		<-listenerStoppedCh
 		httpServerStoppedListeningCh.Signal()
+		klog.V(1).InfoS("[graceful-termination] shutdown event", "name", httpServerStoppedListeningCh.Name())
 	}()
 
-	drainedCh := s.terminationSignals.InFlightRequestsDrained
+	drainedCh := s.lifecycleSignals.InFlightRequestsDrained
 	go func() {
 		defer drainedCh.Signal()
+		defer klog.V(1).InfoS("[graceful-termination] shutdown event", "name", drainedCh.Name())
 
 		// wait for the delayed stopCh before closing the handler chain (it rejects everything after Wait has been called).
 		<-delayedStopCh.Signaled()

staging/src/k8s.io/apiserver/pkg/server/genericapiserver_graceful_termination_test.go

@@ -52,33 +52,33 @@ type result struct {
 	response *http.Response
 }
 
-// wrap a terminationSignal so the test can inject its own callback
+// wrap a lifecycleSignal so the test can inject its own callback
 type wrappedTerminationSignal struct {
-	terminationSignal
-	callback func(bool, string, terminationSignal)
+	lifecycleSignal
+	callback func(bool, string, lifecycleSignal)
 }
 
 func (w *wrappedTerminationSignal) Signal() {
 	var name string
-	if ncw, ok := w.terminationSignal.(*namedChannelWrapper); ok {
+	if ncw, ok := w.lifecycleSignal.(*namedChannelWrapper); ok {
 		name = ncw.name
 	}
 
 	// the callback is invoked before and after the termination event is signaled
 	if w.callback != nil {
-		w.callback(true, name, w.terminationSignal)
+		w.callback(true, name, w.lifecycleSignal)
 	}
-	w.terminationSignal.Signal()
+	w.lifecycleSignal.Signal()
 	if w.callback != nil {
-		w.callback(false, name, w.terminationSignal)
+		w.callback(false, name, w.lifecycleSignal)
 	}
 }
 
-func wrapTerminationSignals(t *testing.T, ts *terminationSignals, callback func(bool, string, terminationSignal)) {
-	newWrappedTerminationSignal := func(delegated terminationSignal) terminationSignal {
+func wrapTerminationSignals(t *testing.T, ts *lifecycleSignals, callback func(bool, string, lifecycleSignal)) {
+	newWrappedTerminationSignal := func(delegated lifecycleSignal) lifecycleSignal {
 		return &wrappedTerminationSignal{
-			terminationSignal: delegated,
-			callback:          callback,
+			lifecycleSignal: delegated,
+			callback:        callback,
 		}
 	}
 
@@ -116,7 +116,7 @@ func TestGracefulTerminationWithKeepListeningDuringGracefulTerminationDisabled(t
 	// record the termination events in the order they are signaled
 	var signalOrderLock sync.Mutex
 	signalOrderGot := make([]string, 0)
-	recordOrderFn := func(before bool, name string, e terminationSignal) {
+	recordOrderFn := func(before bool, name string, e lifecycleSignal) {
 		if !before {
 			return
 		}
@@ -147,7 +147,7 @@ func TestGracefulTerminationWithKeepListeningDuringGracefulTerminationDisabled(t
 		resultGot = doer.Do(newClient(true), shouldUseNewConnection(t), "/echo?message=request-on-a-new-tcp-connection-should-succeed", time.Second)
 		requestMustSucceed(t, resultGot)
 	})
-	steps := func(before bool, name string, e terminationSignal) {
+	steps := func(before bool, name string, e lifecycleSignal) {
 		// Before AfterShutdownDelayDuration event is signaled, the test
 		// will send request(s) to assert on expected behavior.
 		if name == "AfterShutdownDelayDuration" && before {
@@ -157,7 +157,7 @@ func TestGracefulTerminationWithKeepListeningDuringGracefulTerminationDisabled(t
 	}
 
 	// wrap the termination signals of the GenericAPIServer so the test can inject its own callback
-	wrapTerminationSignals(t, &s.terminationSignals, func(before bool, name string, e terminationSignal) {
+	wrapTerminationSignals(t, &s.lifecycleSignals, func(before bool, name string, e lifecycleSignal) {
 		recordOrderFn(before, name, e)
 		steps(before, name, e)
 	})
@@ -192,7 +192,7 @@ func TestGracefulTerminationWithKeepListeningDuringGracefulTerminationDisabled(t
 	}
 
 	// step 4: wait for the HTTP Server listener to have stopped
-	httpServerStoppedListeningCh := s.terminationSignals.HTTPServerStoppedListening
+	httpServerStoppedListeningCh := s.lifecycleSignals.HTTPServerStoppedListening
 	select {
 	case <-httpServerStoppedListeningCh.Signaled():
 	case <-time.After(5 * time.Second):

staging/src/k8s.io/apiserver/pkg/server/lifecycle_signals.go

@@ -16,13 +16,9 @@ limitations under the License.
 
 package server
 
-import (
-	"k8s.io/klog/v2"
-)
-
 /*
 We make an attempt here to identify the events that take place during
-the graceful shutdown of the apiserver.
+lifecycle of the apiserver.
 
 We also identify each event with a name so we can refer to it.
 
@@ -59,49 +55,52 @@ T0 + 70s + up-to 60s: InFlightRequestsDrained: existing in flight requests have
 	  in flight request(s) have drained.
 */
 
-// terminationSignal encapsulates a named apiserver termination event
-type terminationSignal interface {
+// lifecycleSignal encapsulates a named apiserver event
+type lifecycleSignal interface {
 	// Signal signals the event, indicating that the event has occurred.
 	// Signal is idempotent, once signaled the event stays signaled and
 	// it immediately unblocks any goroutine waiting for this event.
 	Signal()
 
-	// Signaled returns a channel that is closed when the underlying termination
-	// event has been signaled. Successive calls to Signaled return the same value.
+	// Signaled returns a channel that is closed when the underlying event
+	// has been signaled. Successive calls to Signaled return the same value.
 	Signaled() <-chan struct{}
+
+	// Name returns the name of the signal, useful for logging.
+	Name() string
 }
 
-// terminationSignals provides an abstraction of the termination events that
-// transpire during the shutdown period of the apiserver. This abstraction makes it easy
+// lifecycleSignals provides an abstraction of the events that
+// transpire during the lifecycle of the apiserver. This abstraction makes it easy
 // for us to write unit tests that can verify expected graceful termination behavior.
 //
 // GenericAPIServer can use these to either:
 //  - signal that a particular termination event has transpired
 //  - wait for a designated termination event to transpire and do some action.
-type terminationSignals struct {
+type lifecycleSignals struct {
 	// ShutdownInitiated event is signaled when an apiserver shutdown has been initiated.
 	// It is signaled when the `stopCh` provided by the main goroutine
 	// receives a KILL signal and is closed as a consequence.
-	ShutdownInitiated terminationSignal
+	ShutdownInitiated lifecycleSignal
 
 	// AfterShutdownDelayDuration event is signaled as soon as ShutdownDelayDuration
 	// has elapsed since the ShutdownInitiated event.
 	// ShutdownDelayDuration allows the apiserver to delay shutdown for some time.
-	AfterShutdownDelayDuration terminationSignal
+	AfterShutdownDelayDuration lifecycleSignal
 
 	// InFlightRequestsDrained event is signaled when the existing requests
 	// in flight have completed. This is used as signal to shut down the audit backends
-	InFlightRequestsDrained terminationSignal
+	InFlightRequestsDrained lifecycleSignal
 
 	// HTTPServerStoppedListening termination event is signaled when the
 	// HTTP Server has stopped listening to the underlying socket.
-	HTTPServerStoppedListening terminationSignal
+	HTTPServerStoppedListening lifecycleSignal
 }
 
-// newTerminationSignals returns an instance of terminationSignals interface to be used
-// to coordinate graceful termination of the apiserver
-func newTerminationSignals() terminationSignals {
-	return terminationSignals{
+// newLifecycleSignals returns an instance of lifecycleSignals interface to be used
+// to coordinate lifecycle of the apiserver
+func newLifecycleSignals() lifecycleSignals {
+	return lifecycleSignals{
 		ShutdownInitiated:          newNamedChannelWrapper("ShutdownInitiated"),
 		AfterShutdownDelayDuration: newNamedChannelWrapper("AfterShutdownDelayDuration"),
 		InFlightRequestsDrained:    newNamedChannelWrapper("InFlightRequestsDrained"),
@@ -109,7 +108,7 @@ func newTerminationSignals() terminationSignals {
 	}
 }
 
-func newNamedChannelWrapper(name string) terminationSignal {
+func newNamedChannelWrapper(name string) lifecycleSignal {
 	return &namedChannelWrapper{
 		name: name,
 		ch:   make(chan struct{}),
@@ -127,10 +126,13 @@ func (e *namedChannelWrapper) Signal() {
 		// already closed, don't close again.
 	default:
 		close(e.ch)
-		klog.V(1).InfoS("[graceful-termination] shutdown event", "name", e.name)
 	}
 }
 
 func (e *namedChannelWrapper) Signaled() <-chan struct{} {
 	return e.ch
 }
+
+func (e *namedChannelWrapper) Name() string {
+	return e.name
+}