apiserver + controllers: enhance context support

27a68aee3a introduced context support for events. Creating an event
broadcaster with context makes tests more resilient against leaking goroutines
when that context gets canceled at the end of a test and enables per-test
output via ktesting.

The context could get passed to the constructor. A cleaner solution is to
enhance context support for the apiserver and then pass the context into the
controller's run method. This ripples up the call stack to all places which
start an apiserver.

cmd/kube-apiserver/app/server.go

@@ -20,6 +20,7 @@ limitations under the License.
 package app
 
 import (
+	"context"
 	"crypto/tls"
 	"fmt"
 	"net/http"
@@ -114,7 +115,7 @@ cluster's shared state through which all other components interact.`,
 			}
 			// add feature enablement metrics
 			utilfeature.DefaultMutableFeatureGate.AddMetrics()
-			return Run(completedOptions, genericapiserver.SetupSignalHandler())
+			return Run(cmd.Context(), completedOptions)
 		},
 		Args: func(cmd *cobra.Command, args []string) error {
 			for _, arg := range args {
@@ -125,6 +126,7 @@ cluster's shared state through which all other components interact.`,
 			return nil
 		},
 	}
+	cmd.SetContext(genericapiserver.SetupSignalContext())
 
 	fs := cmd.Flags()
 	namedFlagSets := s.Flags()
@@ -142,7 +144,7 @@ cluster's shared state through which all other components interact.`,
 }
 
 // Run runs the specified APIServer.  This should never exit.
-func Run(opts options.CompletedOptions, stopCh <-chan struct{}) error {
+func Run(ctx context.Context, opts options.CompletedOptions) error {
 	// To help debugging, immediately log version
 	klog.Infof("Version: %+v", version.Get())
 
@@ -166,7 +168,7 @@ func Run(opts options.CompletedOptions, stopCh <-chan struct{}) error {
 		return err
 	}
 
-	return prepared.Run(stopCh)
+	return prepared.Run(ctx)
 }
 
 // CreateServerChain creates the apiservers connected via delegation.

cmd/kube-apiserver/app/testing/testserver.go

@@ -32,6 +32,7 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"testing"
 	"time"
 
 	"github.com/spf13/pflag"
@@ -56,10 +57,11 @@ import (
 	"k8s.io/klog/v2"
 	"k8s.io/kube-aggregator/pkg/apiserver"
 	"k8s.io/kubernetes/pkg/features"
+	testutil "k8s.io/kubernetes/test/utils"
+	"k8s.io/kubernetes/test/utils/ktesting"
 
 	"k8s.io/kubernetes/cmd/kube-apiserver/app"
 	"k8s.io/kubernetes/cmd/kube-apiserver/app/options"
-	testutil "k8s.io/kubernetes/test/utils"
 )
 
 func init() {
@@ -139,7 +141,9 @@ func NewDefaultTestServerOptions() *TestServerInstanceOptions {
 // Note: we return a tear-down func instead of a stop channel because the later will leak temporary
 // files that because Golang testing's call to os.Exit will not give a stop channel go routine
 // enough time to remove temporary files.
-func StartTestServer(t Logger, instanceOptions *TestServerInstanceOptions, customFlags []string, storageConfig *storagebackend.Config) (result TestServer, err error) {
+func StartTestServer(t ktesting.TB, instanceOptions *TestServerInstanceOptions, customFlags []string, storageConfig *storagebackend.Config) (result TestServer, err error) {
+	tCtx := ktesting.Init(t)
+
 	if instanceOptions == nil {
 		instanceOptions = NewDefaultTestServerOptions()
 	}
@@ -149,12 +153,11 @@ func StartTestServer(t Logger, instanceOptions *TestServerInstanceOptions, custo
 		return result, fmt.Errorf("failed to create temp dir: %v", err)
 	}
 
-	stopCh := make(chan struct{})
 	var errCh chan error
 	tearDown := func() {
-		// Closing stopCh is stopping apiserver and cleaning up
+		// Cancel is stopping apiserver and cleaning up
 		// after itself, including shutting down its storage layer.
-		close(stopCh)
+		tCtx.Cancel("tearing down")
 
 		// If the apiserver was started, let's wait for it to
 		// shutdown clearly.
@@ -359,15 +362,15 @@ func StartTestServer(t Logger, instanceOptions *TestServerInstanceOptions, custo
 	}
 
 	errCh = make(chan error)
-	go func(stopCh <-chan struct{}) {
+	go func() {
 		defer close(errCh)
 		prepared, err := server.PrepareRun()
 		if err != nil {
 			errCh <- err
-		} else if err := prepared.Run(stopCh); err != nil {
+		} else if err := prepared.Run(tCtx); err != nil {
 			errCh <- err
 		}
-	}(stopCh)
+	}()
 
 	client, err := kubernetes.NewForConfig(server.GenericAPIServer.LoopbackClientConfig)
 	if err != nil {
@@ -465,7 +468,7 @@ func StartTestServer(t Logger, instanceOptions *TestServerInstanceOptions, custo
 }
 
 // StartTestServerOrDie calls StartTestServer t.Fatal if it does not succeed.
-func StartTestServerOrDie(t Logger, instanceOptions *TestServerInstanceOptions, flags []string, storageConfig *storagebackend.Config) *TestServer {
+func StartTestServerOrDie(t testing.TB, instanceOptions *TestServerInstanceOptions, flags []string, storageConfig *storagebackend.Config) *TestServer {
 	result, err := StartTestServer(t, instanceOptions, flags, storageConfig)
 	if err == nil {
 		return &result