/*
Copyright 2017 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package mutating

import (
	"context"
	"fmt"
	"net/url"
	"os"
	"reflect"
	"strings"
	"testing"

	"github.com/stretchr/testify/assert"

	"k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apiserver/pkg/admission"
	admissionmetrics "k8s.io/apiserver/pkg/admission/metrics"
	webhooktesting "k8s.io/apiserver/pkg/admission/plugin/webhook/testing"
	auditinternal "k8s.io/apiserver/pkg/apis/audit"
	"k8s.io/apiserver/pkg/endpoints/request"
	"k8s.io/component-base/metrics/testutil"
	clocktesting "k8s.io/utils/clock/testing"
)

// BenchmarkAdmit tests the performance cost of invoking a mutating webhook
func BenchmarkAdmit(b *testing.B) {
	testServerURL := os.Getenv("WEBHOOK_TEST_SERVER_URL")
	if len(testServerURL) == 0 {
		b.Log("warning, WEBHOOK_TEST_SERVER_URL not set, starting in-process server, benchmarks will include webhook cost.")
		b.Log("to run a standalone server, run:")
		b.Log("go run k8s.io/apiserver/pkg/admission/plugin/webhook/testing/main/main.go")
		testServer := webhooktesting.NewTestServer(b)
		testServer.StartTLS()
		defer testServer.Close()
		testServerURL = testServer.URL
	}

	serverURL, err := url.ParseRequestURI(testServerURL)
	if err != nil {
		b.Fatalf("this should never happen? %v", err)
	}

	objectInterfaces := webhooktesting.NewObjectInterfacesForTest()

	stopCh := make(chan struct{})
	defer close(stopCh)

	testCases := append(webhooktesting.NewMutatingTestCases(serverURL, "test-webhooks"),
		webhooktesting.ConvertToMutatingTestCases(webhooktesting.NewNonMutatingTestCases(serverURL), "test-webhooks")...)

	for _, tt := range testCases {
		// For now, skip failure cases or tests that explicitly skip benchmarking
		if !tt.ExpectAllow || tt.SkipBenchmark {
			continue
		}
		b.Run(tt.Name, func(b *testing.B) {
			wh, err := NewMutatingWebhook(nil)
			if err != nil {
				b.Errorf("failed to create mutating webhook: %v", err)
				return
			}

			ns := "webhook-test"
			client, informer := webhooktesting.NewFakeMutatingDataSource(ns, tt.Webhooks, stopCh)

			wh.SetAuthenticationInfoResolverWrapper(webhooktesting.Wrapper(webhooktesting.NewAuthenticationInfoResolver(new(int32))))
			wh.SetServiceResolver(webhooktesting.NewServiceResolver(*serverURL))
			wh.SetExternalKubeClientSet(client)
			wh.SetExternalKubeInformerFactory(informer)

			informer.Start(stopCh)
			informer.WaitForCacheSync(stopCh)

			if err = wh.ValidateInitialization(); err != nil {
				b.Errorf("failed to validate initialization: %v", err)
				return
			}

			var attr admission.Attributes
			if tt.IsCRD {
				attr = webhooktesting.NewAttributeUnstructured(ns, tt.AdditionalLabels, tt.IsDryRun)
			} else {
				attr = webhooktesting.NewAttribute(ns, tt.AdditionalLabels, tt.IsDryRun)
			}

			b.ResetTimer()
			b.RunParallel(func(pb *testing.PB) {
				for pb.Next() {
					wh.Admit(context.TODO(), attr, objectInterfaces)
				}
			})
		})
	}
}

// TestAdmit tests that MutatingWebhook#Admit works as expected
func TestAdmit(t *testing.T) {
	testServer := webhooktesting.NewTestServer(t)
	testServer.StartTLS()
	defer testServer.Close()
	serverURL, err := url.ParseRequestURI(testServer.URL)
	if err != nil {
		t.Fatalf("this should never happen? %v", err)
	}

	objectInterfaces := webhooktesting.NewObjectInterfacesForTest()

	stopCh := make(chan struct{})
	defer close(stopCh)

	testCases := append(webhooktesting.NewMutatingTestCases(serverURL, "test-webhooks"),
		webhooktesting.ConvertToMutatingTestCases(webhooktesting.NewNonMutatingTestCases(serverURL), "test-webhooks")...)

	for _, tt := range testCases {
		t.Run(tt.Name, func(t *testing.T) {
			wh, err := NewMutatingWebhook(nil)
			if err != nil {
				t.Errorf("failed to create mutating webhook: %v", err)
				return
			}

			ns := "webhook-test"
			client, informer := webhooktesting.NewFakeMutatingDataSource(ns, tt.Webhooks, stopCh)

			wh.SetAuthenticationInfoResolverWrapper(webhooktesting.Wrapper(webhooktesting.NewAuthenticationInfoResolver(new(int32))))
			wh.SetServiceResolver(webhooktesting.NewServiceResolver(*serverURL))
			wh.SetExternalKubeClientSet(client)
			wh.SetExternalKubeInformerFactory(informer)

			informer.Start(stopCh)
			informer.WaitForCacheSync(stopCh)

			if err = wh.ValidateInitialization(); err != nil {
				t.Errorf("failed to validate initialization: %v", err)
				return
			}

			var attr admission.Attributes
			if tt.IsCRD {
				attr = webhooktesting.NewAttributeUnstructured(ns, tt.AdditionalLabels, tt.IsDryRun)
			} else {
				attr = webhooktesting.NewAttribute(ns, tt.AdditionalLabels, tt.IsDryRun)
			}

			if len(tt.ExpectRejectionMetrics) > 0 {
				admissionmetrics.Metrics.WebhookRejectionGathererForTest().Reset()
			}
			err = wh.Admit(context.TODO(), attr, objectInterfaces)
			if tt.ExpectAllow != (err == nil) {
				t.Errorf("expected allowed=%v, but got err=%v", tt.ExpectAllow, err)
			}
			if tt.ExpectLabels != nil {
				if !reflect.DeepEqual(tt.ExpectLabels, attr.GetObject().(metav1.Object).GetLabels()) {
					t.Errorf("expected labels '%v', but got '%v'", tt.ExpectLabels, attr.GetObject().(metav1.Object).GetLabels())
				}
			}
			// ErrWebhookRejected is not an error for our purposes
			if tt.ErrorContains != "" {
				if err == nil || !strings.Contains(err.Error(), tt.ErrorContains) {
					t.Errorf("expected an error saying %q, but got: %v", tt.ErrorContains, err)
				}
			}
			if statusErr, isStatusErr := err.(*errors.StatusError); err != nil && !isStatusErr {
				t.Errorf("expected a StatusError, got %T", err)
			} else if isStatusErr {
				if statusErr.ErrStatus.Code != tt.ExpectStatusCode {
					t.Errorf("expected status code %d, got %d", tt.ExpectStatusCode, statusErr.ErrStatus.Code)
				}
			}
			if len(tt.ExpectRejectionMetrics) > 0 {
				expectedMetrics := `
# HELP apiserver_admission_webhook_rejection_count [ALPHA] Admission webhook rejection count, identified by name and broken out for each admission type (validating or admit) and operation. Additional labels specify an error type (calling_webhook_error or apiserver_internal_error if an error occurred; no_error otherwise) and optionally a non-zero rejection code if the webhook rejects the request with an HTTP status code (honored by the apiserver when the code is greater or equal to 400). Codes greater than 600 are truncated to 600, to keep the metrics cardinality bounded.
# TYPE apiserver_admission_webhook_rejection_count counter
` + tt.ExpectRejectionMetrics + "\n"
				if err := testutil.CollectAndCompare(admissionmetrics.Metrics.WebhookRejectionGathererForTest(), strings.NewReader(expectedMetrics), "apiserver_admission_webhook_rejection_count"); err != nil {
					t.Errorf("unexpected collecting result:\n%s", err)
				}
			}
			fakeAttr, ok := attr.(*webhooktesting.FakeAttributes)
			if !ok {
				t.Errorf("Unexpected error, failed to convert attr to webhooktesting.FakeAttributes")
				return
			}
			if len(tt.ExpectAnnotations) == 0 {
				assert.Empty(t, fakeAttr.GetAnnotations(auditinternal.LevelMetadata), tt.Name+": annotations not set as expected.")
			} else {
				assert.Equal(t, tt.ExpectAnnotations, fakeAttr.GetAnnotations(auditinternal.LevelMetadata), tt.Name+": annotations not set as expected.")
			}
			reinvocationCtx := fakeAttr.Attributes.GetReinvocationContext()
			reinvocationCtx.SetIsReinvoke()
			for webhook, expectReinvoke := range tt.ExpectReinvokeWebhooks {
				shouldReinvoke := reinvocationCtx.Value(PluginName).(*webhookReinvokeContext).ShouldReinvokeWebhook(fmt.Sprintf("test-webhooks/%s/0", webhook))
				if expectReinvoke != shouldReinvoke {
					t.Errorf("expected reinvocationContext.ShouldReinvokeWebhook(%s)=%t, but got %t", webhook, expectReinvoke, shouldReinvoke)
				}
			}
		})
	}
}

// TestAdmitCachedClient tests that MutatingWebhook#Admit should cache restClient
func TestAdmitCachedClient(t *testing.T) {
	testServer := webhooktesting.NewTestServer(t)
	testServer.StartTLS()
	defer testServer.Close()
	serverURL, err := url.ParseRequestURI(testServer.URL)
	if err != nil {
		t.Fatalf("this should never happen? %v", err)
	}

	objectInterfaces := webhooktesting.NewObjectInterfacesForTest()

	stopCh := make(chan struct{})
	defer close(stopCh)

	wh, err := NewMutatingWebhook(nil)
	if err != nil {
		t.Fatalf("Failed to create mutating webhook: %v", err)
	}
	wh.SetServiceResolver(webhooktesting.NewServiceResolver(*serverURL))

	for _, tt := range webhooktesting.NewCachedClientTestcases(serverURL) {
		ns := "webhook-test"
		client, informer := webhooktesting.NewFakeMutatingDataSource(ns, webhooktesting.ConvertToMutatingWebhooks(tt.Webhooks), stopCh)

		// override the webhook source. The client cache will stay the same.
		cacheMisses := new(int32)
		wh.SetAuthenticationInfoResolverWrapper(webhooktesting.Wrapper(webhooktesting.NewAuthenticationInfoResolver(cacheMisses)))
		wh.SetExternalKubeClientSet(client)
		wh.SetExternalKubeInformerFactory(informer)

		informer.Start(stopCh)
		informer.WaitForCacheSync(stopCh)

		if err = wh.ValidateInitialization(); err != nil {
			t.Errorf("%s: failed to validate initialization: %v", tt.Name, err)
			continue
		}

		err = wh.Admit(context.TODO(), webhooktesting.NewAttribute(ns, nil, false), objectInterfaces)
		if tt.ExpectAllow != (err == nil) {
			t.Errorf("%s: expected allowed=%v, but got err=%v", tt.Name, tt.ExpectAllow, err)
		}

		if tt.ExpectCacheMiss && *cacheMisses == 0 {
			t.Errorf("%s: expected cache miss, but got no AuthenticationInfoResolver call", tt.Name)
		}

		if !tt.ExpectCacheMiss && *cacheMisses > 0 {
			t.Errorf("%s: expected client to be cached, but got %d AuthenticationInfoResolver calls", tt.Name, *cacheMisses)
		}
	}
}

// TestWebhookDuration tests that MutatingWebhook#Admit sets webhook duration in context correctly
func TestWebhookDuration(ts *testing.T) {
	clk := clocktesting.FakeClock{}
	testServer := webhooktesting.NewTestServerWithHandler(ts, webhooktesting.ClockSteppingWebhookHandler(ts, &clk))
	testServer.StartTLS()
	defer testServer.Close()
	serverURL, err := url.ParseRequestURI(testServer.URL)
	if err != nil {
		ts.Fatalf("this should never happen? %v", err)
	}

	objectInterfaces := webhooktesting.NewObjectInterfacesForTest()

	stopCh := make(chan struct{})
	defer close(stopCh)

	for _, test := range webhooktesting.NewValidationDurationTestCases(serverURL) {
		ts.Run(test.Name, func(t *testing.T) {
			ctx := context.TODO()
			if test.InitContext {
				ctx = request.WithLatencyTrackersAndCustomClock(ctx, &clk)
			}
			wh, err := NewMutatingWebhook(nil)
			if err != nil {
				t.Errorf("failed to create mutating webhook: %v", err)
				return
			}

			ns := "webhook-test"
			client, informer := webhooktesting.NewFakeMutatingDataSource(ns, webhooktesting.ConvertToMutatingWebhooks(test.Webhooks), stopCh)

			wh.SetAuthenticationInfoResolverWrapper(webhooktesting.Wrapper(webhooktesting.NewAuthenticationInfoResolver(new(int32))))
			wh.SetServiceResolver(webhooktesting.NewServiceResolver(*serverURL))
			wh.SetExternalKubeClientSet(client)
			wh.SetExternalKubeInformerFactory(informer)

			informer.Start(stopCh)
			informer.WaitForCacheSync(stopCh)

			if err = wh.ValidateInitialization(); err != nil {
				t.Errorf("failed to validate initialization: %v", err)
				return
			}

			_ = wh.Admit(ctx, webhooktesting.NewAttribute(ns, nil, test.IsDryRun), objectInterfaces)
			wd, ok := request.LatencyTrackersFrom(ctx)
			if !ok {
				if test.InitContext {
					t.Errorf("expected webhook duration to be initialized")
				}
				return
			}
			if !test.InitContext {
				t.Errorf("expected webhook duration to not be initialized")
				return
			}
			if wd.MutatingWebhookTracker.GetLatency() != test.ExpectedDurationSum {
				t.Errorf("expected admit duration %q got %q", test.ExpectedDurationSum, wd.MutatingWebhookTracker.GetLatency())
			}
			if wd.ValidatingWebhookTracker.GetLatency() != 0 {
				t.Errorf("expected validate duraion to be equal to 0 got %q", wd.ValidatingWebhookTracker.GetLatency())
			}
		})
	}
}
