Merge pull request #97206 from tkashem/panic

clean up executing request on panic

staging/src/k8s.io/apiserver/pkg/server/filters/BUILD

@@ -21,10 +21,13 @@ go_test(
         "//staging/src/k8s.io/api/flowcontrol/v1beta1:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/api/errors:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/runtime:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/runtime/schema:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/types:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/diff:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/runtime:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/sets:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/util/wait:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/apis/flowcontrol/bootstrap:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/authentication/user:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/endpoints/filters:go_default_library",
@@ -34,7 +37,11 @@ go_test(
         "//staging/src/k8s.io/apiserver/pkg/util/flowcontrol:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/util/flowcontrol/metrics:go_default_library",
+        "//staging/src/k8s.io/client-go/informers:go_default_library",
+        "//staging/src/k8s.io/client-go/kubernetes:go_default_library",
+        "//staging/src/k8s.io/client-go/kubernetes/fake:go_default_library",
         "//staging/src/k8s.io/component-base/metrics/legacyregistry:go_default_library",
+        "//staging/src/k8s.io/component-base/metrics/testutil:go_default_library",
         "//vendor/golang.org/x/net/http2:go_default_library",
         "//vendor/k8s.io/klog/v2:go_default_library",
     ],

staging/src/k8s.io/apiserver/pkg/server/filters/priority-and-fairness_test.go

@@ -21,12 +21,19 @@ import (
 	"fmt"
 	"net/http"
 	"net/http/httptest"
+	"net/url"
+	"reflect"
+	"strings"
 	"sync"
 	"testing"
 	"time"
 
 	flowcontrol "k8s.io/api/flowcontrol/v1beta1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/apimachinery/pkg/util/sets"
+	"k8s.io/apimachinery/pkg/util/wait"
 	"k8s.io/apiserver/pkg/apis/flowcontrol/bootstrap"
 	"k8s.io/apiserver/pkg/authentication/user"
 	apifilters "k8s.io/apiserver/pkg/endpoints/filters"
@@ -36,7 +43,11 @@ import (
 	utilflowcontrol "k8s.io/apiserver/pkg/util/flowcontrol"
 	fq "k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing"
 	fcmetrics "k8s.io/apiserver/pkg/util/flowcontrol/metrics"
+	"k8s.io/client-go/informers"
+	clientset "k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/kubernetes/fake"
 	"k8s.io/component-base/metrics/legacyregistry"
+	"k8s.io/component-base/metrics/testutil"
 )
 
 type mockDecision int
@@ -333,6 +344,243 @@ func TestApfCancelWaitRequest(t *testing.T) {
 	})
 }
 
+func TestPriorityAndFairnessWithPanicRecoverAndTimeoutFilter(t *testing.T) {
+	fcmetrics.Register()
+
+	t.Run("priority level concurrency is set to 1, request handler panics, next request should not be rejected", func(t *testing.T) {
+		const (
+			requestTimeout                                        = time.Minute
+			userName                                              = "alice"
+			fsName                                                = "test-fs"
+			plName                                                = "test-pl"
+			serverConcurrency, plConcurrencyShares, plConcurrency = 1, 1, 1
+		)
+
+		objects := newConfiguration(fsName, plName, userName, flowcontrol.LimitResponseTypeReject, plConcurrencyShares)
+		clientset := newClientset(t, objects...)
+		// this test does not rely on resync, so resync period is set to zero
+		factory := informers.NewSharedInformerFactory(clientset, 0)
+		controller := utilflowcontrol.New(factory, clientset.FlowcontrolV1beta1(), serverConcurrency, requestTimeout/4)
+
+		stopCh, controllerCompletedCh := make(chan struct{}), make(chan struct{})
+		factory.Start(stopCh)
+
+		// wait for the informer cache to sync.
+		timeout, cancel := context.WithTimeout(context.TODO(), 5*time.Second)
+		defer cancel()
+		cacheSyncDone := factory.WaitForCacheSync(timeout.Done())
+		if names := unsyncedInformers(cacheSyncDone); len(names) > 0 {
+			t.Fatalf("WaitForCacheSync did not successfully complete, resources=%#v", names)
+		}
+
+		var controllerErr error
+		go func() {
+			defer close(controllerCompletedCh)
+			controllerErr = controller.Run(stopCh)
+		}()
+
+		// make sure that apf controller syncs the priority level configuration object we are using in this test.
+		// read the metrics and ensure the concurrency limit for our priority level is set to the expected value.
+		pollErr := wait.PollImmediate(100*time.Millisecond, 5*time.Second, func() (done bool, err error) {
+			if err := gaugeValueMatch("apiserver_flowcontrol_request_concurrency_limit", map[string]string{"priority_level": plName}, plConcurrency); err != nil {
+				t.Logf("polling retry - error: %s", err)
+				return false, nil
+			}
+			return true, nil
+		})
+		if pollErr != nil {
+			t.Fatalf("expected the apf controller to sync the priotity level configuration object: %s", "test-pl")
+		}
+
+		var executed bool
+		// we will raise a panic for the first request.
+		firstRequestPathPanic := "/request/panic"
+		requestHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			executed = true
+			expectMatchingAPFHeaders(t, w, fsName, plName)
+
+			if r.URL.Path == firstRequestPathPanic {
+				panic(fmt.Errorf("request handler panic'd as designed - %#v", r.RequestURI))
+			}
+		})
+		handler := newHandlerChain(t, requestHandler, controller, userName, requestTimeout)
+
+		server, requestGetter := newHTTP2ServerWithClient(handler)
+		defer server.Close()
+
+		var err error
+		_, err = requestGetter(firstRequestPathPanic)
+		if !executed {
+			t.Errorf("expected inner handler to be executed for request: %s", firstRequestPathPanic)
+		}
+		expectResetStreamError(t, err)
+
+		executed = false
+		// the second request should be served successfully.
+		secondRequestPathShouldWork := "/request/should-work"
+		response, err := requestGetter(secondRequestPathShouldWork)
+		if !executed {
+			t.Errorf("expected inner handler to be executed for request: %s", secondRequestPathShouldWork)
+		}
+		if err != nil {
+			t.Errorf("expected request: %s to succeed, but got error: %#v", secondRequestPathShouldWork, err)
+		}
+		if response.StatusCode != http.StatusOK {
+			t.Errorf("expected HTTP status code: %d for request: %s, but got: %#v", http.StatusOK, secondRequestPathShouldWork, response)
+		}
+
+		close(stopCh)
+		t.Log("waiting for the controller to shutdown")
+		<-controllerCompletedCh
+
+		if controllerErr != nil {
+			t.Errorf("expected a nil error from controller, but got: %#v", controllerErr)
+		}
+	})
+}
+
+// returns a started http2 server, with a client function to send request to the server.
+func newHTTP2ServerWithClient(handler http.Handler) (*httptest.Server, func(path string) (*http.Response, error)) {
+	server := httptest.NewUnstartedServer(handler)
+	server.EnableHTTP2 = true
+	server.StartTLS()
+
+	return server, func(path string) (*http.Response, error) {
+		return server.Client().Get(server.URL + path)
+	}
+}
+
+// verifies that the expected flow schema and priority level UIDs are attached to the header.
+func expectMatchingAPFHeaders(t *testing.T, w http.ResponseWriter, expectedFS, expectedPL string) {
+	if w == nil {
+		t.Fatal("expected a non nil HTTP response")
+	}
+
+	key := flowcontrol.ResponseHeaderMatchedFlowSchemaUID
+	if value := w.Header().Get(key); expectedFS != value {
+		t.Fatalf("expected HTTP header %s to have value %q, but got: %q", key, expectedFS, value)
+	}
+
+	key = flowcontrol.ResponseHeaderMatchedPriorityLevelConfigurationUID
+	if value := w.Header().Get(key); expectedPL != value {
+		t.Fatalf("expected HTTP header %s to have value %q, but got %q", key, expectedPL, value)
+	}
+}
+
+// when a request panics, http2 resets the stream with an INTERNAL_ERROR message
+func expectResetStreamError(t *testing.T, err error) {
+	if err == nil {
+		t.Fatalf("expected the server to send an error, but got nil")
+	}
+
+	uerr, ok := err.(*url.Error)
+	if !ok {
+		t.Fatalf("expected the error to be of type *url.Error, but got: %T", err)
+	}
+	if !strings.Contains(uerr.Error(), "INTERNAL_ERROR") {
+		t.Fatalf("expected a stream reset error, but got: %s", uerr.Error())
+	}
+}
+
+func newClientset(t *testing.T, objects ...runtime.Object) clientset.Interface {
+	clientset := fake.NewSimpleClientset(objects...)
+	if clientset == nil {
+		t.Fatal("unable to create fake client set")
+	}
+	return clientset
+}
+
+// builds a chain of handlers that include the panic recovery and timeout filter, so we can simulate the behavior of
+// a real apiserver.
+// the specified user is added as the authenticated user to the request context.
+func newHandlerChain(t *testing.T, handler http.Handler, filter utilflowcontrol.Interface, userName string, requestTimeout time.Duration) http.Handler {
+	requestInfoFactory := &apirequest.RequestInfoFactory{APIPrefixes: sets.NewString("apis", "api"), GrouplessAPIPrefixes: sets.NewString("api")}
+	longRunningRequestCheck := BasicLongRunningRequestCheck(sets.NewString("watch"), sets.NewString("proxy"))
+
+	apfHandler := WithPriorityAndFairness(handler, longRunningRequestCheck, filter)
+
+	// add the handler in the chain that adds the specified user to the request context
+	handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		r = r.WithContext(apirequest.WithUser(r.Context(), &user.DefaultInfo{
+			Name:   userName,
+			Groups: []string{user.AllAuthenticated},
+		}))
+
+		apfHandler.ServeHTTP(w, r)
+	})
+
+	handler = WithTimeoutForNonLongRunningRequests(handler, longRunningRequestCheck, requestTimeout)
+	handler = apifilters.WithRequestInfo(handler, requestInfoFactory)
+	handler = WithPanicRecovery(handler, requestInfoFactory)
+	return handler
+}
+
+func unsyncedInformers(status map[reflect.Type]bool) []string {
+	names := make([]string, 0)
+
+	for objType, synced := range status {
+		if !synced {
+			names = append(names, objType.Name())
+		}
+	}
+
+	return names
+}
+
+func newConfiguration(fsName, plName, user string, responseType flowcontrol.LimitResponseType, concurrency int32) []runtime.Object {
+	fs := &flowcontrol.FlowSchema{
+		ObjectMeta: metav1.ObjectMeta{
+			Name: fsName,
+			UID:  types.UID(fsName),
+		},
+		Spec: flowcontrol.FlowSchemaSpec{
+			MatchingPrecedence: 1,
+			PriorityLevelConfiguration: flowcontrol.PriorityLevelConfigurationReference{
+				Name: plName,
+			},
+			DistinguisherMethod: &flowcontrol.FlowDistinguisherMethod{
+				Type: flowcontrol.FlowDistinguisherMethodByUserType,
+			},
+			Rules: []flowcontrol.PolicyRulesWithSubjects{
+				{
+					Subjects: []flowcontrol.Subject{
+						{
+							Kind: flowcontrol.SubjectKindUser,
+							User: &flowcontrol.UserSubject{
+								Name: user,
+							},
+						},
+					},
+					NonResourceRules: []flowcontrol.NonResourcePolicyRule{
+						{
+							Verbs:           []string{flowcontrol.VerbAll},
+							NonResourceURLs: []string{flowcontrol.NonResourceAll},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	pl := &flowcontrol.PriorityLevelConfiguration{
+		ObjectMeta: metav1.ObjectMeta{
+			Name: plName,
+			UID:  types.UID(plName),
+		},
+		Spec: flowcontrol.PriorityLevelConfigurationSpec{
+			Type: flowcontrol.PriorityLevelEnablementLimited,
+			Limited: &flowcontrol.LimitedPriorityLevelConfiguration{
+				AssuredConcurrencyShares: concurrency,
+				LimitResponse: flowcontrol.LimitResponse{
+					Type: responseType,
+				},
+			},
+		},
+	}
+
+	return []runtime.Object{fs, pl}
+}
+
 // gathers and checks the metrics.
 func checkForExpectedMetrics(t *testing.T, expectedMetrics []string) {
 	metricsFamily, err := legacyregistry.DefaultGatherer.Gather()
@@ -353,3 +601,40 @@ func checkForExpectedMetrics(t *testing.T, expectedMetrics []string) {
 		}
 	}
 }
+
+// gaugeValueMatch ensures that the value of gauge metrics matching the labelFilter is as expected.
+func gaugeValueMatch(name string, labelFilter map[string]string, wantValue int) error {
+	metrics, err := legacyregistry.DefaultGatherer.Gather()
+	if err != nil {
+		return fmt.Errorf("failed to gather metrics: %s", err)
+	}
+
+	sum := 0
+	familyMatch, labelMatch := false, false
+	for _, mf := range metrics {
+		if mf.GetName() != name {
+			continue
+		}
+
+		familyMatch = true
+		for _, metric := range mf.GetMetric() {
+			if !testutil.LabelsMatch(metric, labelFilter) {
+				continue
+			}
+
+			labelMatch = true
+			sum += int(metric.GetGauge().GetValue())
+		}
+	}
+	if !familyMatch {
+		return fmt.Errorf("expected to find the metric family: %s in the gathered result", name)
+	}
+	if !labelMatch {
+		return fmt.Errorf("expected to find metrics with matching labels: %#+v", labelFilter)
+	}
+	if wantValue != sum {
+		return fmt.Errorf("expected the sum to be: %d, but got: %d for gauge metric: %s with labels %#+v", wantValue, sum, name, labelFilter)
+	}
+
+	return nil
+}

staging/src/k8s.io/apiserver/pkg/util/flowcontrol/apf_filter.go

@@ -130,21 +130,28 @@ func (cfgCtlr *configController) Handle(ctx context.Context, requestDigest Reque
 	}
 	klog.V(7).Infof("Handle(%#+v) => fsName=%q, distMethod=%#+v, plName=%q, isExempt=%v, queued=%v", requestDigest, fs.Name, fs.Spec.DistinguisherMethod, pl.Name, isExempt, queued)
 	var executed bool
-	idle := req.Finish(func() {
+	idle, panicking := true, true
+	defer func() {
+		klog.V(7).Infof("Handle(%#+v) => fsName=%q, distMethod=%#+v, plName=%q, isExempt=%v, queued=%v, Finish() => panicking=%v idle=%v",
+			requestDigest, fs.Name, fs.Spec.DistinguisherMethod, pl.Name, isExempt, queued, panicking, idle)
+		if idle {
+			cfgCtlr.maybeReap(pl.Name)
+		}
+	}()
+	idle = req.Finish(func() {
 		if queued {
 			metrics.ObserveWaitingDuration(pl.Name, fs.Name, strconv.FormatBool(req != nil), time.Since(startWaitingTime))
 		}
 		metrics.AddDispatch(pl.Name, fs.Name)
 		executed = true
 		startExecutionTime := time.Now()
+		defer func() {
+			metrics.ObserveExecutionDuration(pl.Name, fs.Name, time.Since(startExecutionTime))
+		}()
 		execFn()
-		metrics.ObserveExecutionDuration(pl.Name, fs.Name, time.Since(startExecutionTime))
 	})
 	if queued && !executed {
 		metrics.ObserveWaitingDuration(pl.Name, fs.Name, strconv.FormatBool(req != nil), time.Since(startWaitingTime))
 	}
-	klog.V(7).Infof("Handle(%#+v) => fsName=%q, distMethod=%#+v, plName=%q, isExempt=%v, queued=%v, Finish() => idle=%v", requestDigest, fs.Name, fs.Spec.DistinguisherMethod, pl.Name, isExempt, queued, idle)
-	if idle {
-		cfgCtlr.maybeReap(pl.Name)
-	}
+	panicking = false
 }

staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/queueset/queueset.go

@@ -316,8 +316,15 @@ func (req *request) Finish(execFn func()) bool {
 	if !exec {
 		return idle
 	}
-	execFn()
-	return req.qs.finishRequestAndDispatchAsMuchAsPossible(req)
+	func() {
+		defer func() {
+			idle = req.qs.finishRequestAndDispatchAsMuchAsPossible(req)
+		}()
+
+		execFn()
+	}()
+
+	return idle
 }
 
 func (req *request) wait() (bool, bool) {

staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/queueset/queueset_test.go

@@ -18,6 +18,7 @@ package queueset
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"math"
 	"reflect"
@@ -714,6 +715,67 @@ func TestContextCancel(t *testing.T) {
 	}
 }
 
+func TestTotalRequestsExecutingWithPanic(t *testing.T) {
+	metrics.Register()
+	metrics.Reset()
+	now := time.Now()
+	clk, counter := testclock.NewFakeEventClock(now, 0, nil)
+	qsf := NewQueueSetFactory(clk, counter)
+	qCfg := fq.QueuingConfig{
+		Name:             "TestTotalRequestsExecutingWithPanic",
+		DesiredNumQueues: 0,
+		RequestWaitLimit: 15 * time.Second,
+	}
+	qsc, err := qsf.BeginConstruction(qCfg, newObserverPair(clk))
+	if err != nil {
+		t.Fatal(err)
+	}
+	qs := qsc.Complete(fq.DispatchingConfig{ConcurrencyLimit: 1})
+	counter.Add(1) // account for the goroutine running this test
+
+	queue, ok := qs.(*queueSet)
+	if !ok {
+		t.Fatalf("expected a QueueSet of type: %T but got: %T", &queueSet{}, qs)
+	}
+	if queue.totRequestsExecuting != 0 {
+		t.Fatalf("precondition: expected total requests currently executing of the QueueSet to be 0, but got: %d", queue.totRequestsExecuting)
+	}
+	if queue.dCfg.ConcurrencyLimit != 1 {
+		t.Fatalf("precondition: expected concurrency limit of the QueueSet to be 1, but got: %d", queue.dCfg.ConcurrencyLimit)
+	}
+
+	ctx := context.Background()
+	req, _ := qs.StartRequest(ctx, 1, "", "fs", "test", "one", func(inQueue bool) {})
+	if req == nil {
+		t.Fatal("expected a Request object from StartRequest, but got nil")
+	}
+
+	panicErrExpected := errors.New("apiserver panic'd")
+	var panicErrGot interface{}
+	func() {
+		defer func() {
+			panicErrGot = recover()
+		}()
+
+		req.Finish(func() {
+			// verify that total requests executing goes up by 1 since the request is executing.
+			if queue.totRequestsExecuting != 1 {
+				t.Fatalf("expected total requests currently executing of the QueueSet to be 1, but got: %d", queue.totRequestsExecuting)
+			}
+
+			panic(panicErrExpected)
+		})
+	}()
+
+	// verify that the panic was from us (above)
+	if panicErrExpected != panicErrGot {
+		t.Errorf("expected panic error: %#v, but got: %#v", panicErrExpected, panicErrGot)
+	}
+	if queue.totRequestsExecuting != 0 {
+		t.Errorf("expected total requests currently executing of the QueueSet to be 0, but got: %d", queue.totRequestsExecuting)
+	}
+}
+
 func newObserverPair(clk clock.PassiveClock) metrics.TimedObserverPair {
 	return metrics.PriorityLevelConcurrencyObserverPairGenerator.Generate(1, 1, []string{"test"})
 }