Adds warning for missing memory limit for activeGate

src/api/v1beta1/activegate_types.go

@@ -45,10 +45,10 @@ var (
 )
 
 var ActiveGateDisplayNames = map[CapabilityDisplayName]struct{}{
-	RoutingCapability.DisplayName:       struct{}{},
-	KubeMonCapability.DisplayName:       struct{}{},
-	MetricsIngestCapability.DisplayName: struct{}{},
-	DynatraceApiCapability.DisplayName:  struct{}{},
+	RoutingCapability.DisplayName:       {},
+	KubeMonCapability.DisplayName:       {},
+	MetricsIngestCapability.DisplayName: {},
+	DynatraceApiCapability.DisplayName:  {},
 }
 
 type ActiveGateSpec struct {

src/webhook/validation/activegate.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 
 	dynatracev1beta1 "github.com/Dynatrace/dynatrace-operator/src/api/v1beta1"
+	corev1 "k8s.io/api/core/v1"
 )
 
 const (
@@ -17,6 +18,7 @@ Make sure you correctly specify the ActiveGate capabilities in your custom resou
 	errorDuplicateActiveGateCapability = `The DynaKube's specification tries to specify duplicate capabilities in the ActiveGate section, duplicate capability=%s.
 Make sure you don't duplicate an Activegate capability in your custom resource.
 `
+	warningMissingActiveGateMemoryLimit = `ActiveGate specification missing memory limits. Can cause excess memory usage.`
 )
 
 func conflictingActiveGateConfiguration(dv *dynakubeValidator, dynakube *dynatracev1beta1.DynaKube) string {
@@ -54,3 +56,16 @@ func invalidActiveGateCapabilities(dv *dynakubeValidator, dynakube *dynatracev1b
 	}
 	return ""
 }
+
+func missingActiveGateMemoryLimit(dv *dynakubeValidator, dynakube *dynatracev1beta1.DynaKube) string {
+	if dynakube.ActiveGateMode() {
+		if !memoryLimitSet(dynakube.Spec.ActiveGate.Resources) {
+			return warningMissingActiveGateMemoryLimit
+		}
+	}
+	return ""
+}
+
+func memoryLimitSet(resources corev1.ResourceRequirements) bool {
+	return resources.Limits != nil && resources.Limits.Memory() != nil
+}

src/webhook/validation/activegate_test.go

@@ -5,6 +5,8 @@ import (
 	"testing"
 
 	dynatracev1beta1 "github.com/Dynatrace/dynatrace-operator/src/api/v1beta1"
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/resource"
 )
 
 func TestConflictingActiveGateConfiguration(t *testing.T) {
@@ -23,7 +25,7 @@ func TestConflictingActiveGateConfiguration(t *testing.T) {
 			},
 		})
 
-		assertAllowedResponseWithoutWarnings(t, &dynatracev1beta1.DynaKube{
+		assertAllowedResponseWithWarnings(t, 1, &dynatracev1beta1.DynaKube{
 			ObjectMeta: defaultDynakubeObjectMeta,
 			Spec: dynatracev1beta1.DynaKubeSpec{
 				APIURL: testApiUrl,
@@ -36,7 +38,7 @@ func TestConflictingActiveGateConfiguration(t *testing.T) {
 			},
 		})
 
-		assertAllowedResponseWithWarnings(t, 2, &dynatracev1beta1.DynaKube{
+		assertAllowedResponseWithWarnings(t, 3, &dynatracev1beta1.DynaKube{
 			ObjectMeta: defaultDynakubeObjectMeta,
 			Spec: dynatracev1beta1.DynaKubeSpec{
 				APIURL: testApiUrl,
@@ -106,3 +108,44 @@ func TestInvalidActiveGateCapabilities(t *testing.T) {
 			})
 	})
 }
+
+func TestMissingActiveGateMemoryLimit(t *testing.T) {
+	t.Run(`memory warning in activeGate mode`, func(t *testing.T) {
+		assertAllowedResponseWithWarnings(t, 1,
+			&dynatracev1beta1.DynaKube{
+				ObjectMeta: defaultDynakubeObjectMeta,
+				Spec: dynatracev1beta1.DynaKubeSpec{
+					APIURL: testApiUrl,
+					ActiveGate: dynatracev1beta1.ActiveGateSpec{
+						Capabilities: []dynatracev1beta1.CapabilityDisplayName{
+							dynatracev1beta1.RoutingCapability.DisplayName,
+						},
+						CapabilityProperties: dynatracev1beta1.CapabilityProperties{
+							Resources: corev1.ResourceRequirements{},
+						},
+					},
+				},
+			})
+	})
+	t.Run(`no memory warning in activeGate mode with memory limit`, func(t *testing.T) {
+		assertAllowedResponseWithoutWarnings(t,
+			&dynatracev1beta1.DynaKube{
+				ObjectMeta: defaultDynakubeObjectMeta,
+				Spec: dynatracev1beta1.DynaKubeSpec{
+					APIURL: testApiUrl,
+					ActiveGate: dynatracev1beta1.ActiveGateSpec{
+						Capabilities: []dynatracev1beta1.CapabilityDisplayName{
+							dynatracev1beta1.RoutingCapability.DisplayName,
+						},
+						CapabilityProperties: dynatracev1beta1.CapabilityProperties{
+							Resources: corev1.ResourceRequirements{
+								Limits: corev1.ResourceList{
+									corev1.ResourceLimitsMemory: *resource.NewMilliQuantity(1, ""),
+								},
+							},
+						},
+					},
+				},
+			})
+	})
+}

src/webhook/validation/config.go

@@ -24,4 +24,5 @@ var validators = []validator{
 var warnings = []validator{
 	oneAgentModePreviewWarning,
 	metricIngestPreviewWarning,
+	missingActiveGateMemoryLimit,
 }

src/webhook/validation/validation.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"net/http"
+	"strings"
 
 	dynatracev1beta1 "github.com/Dynatrace/dynatrace-operator/src/api/v1beta1"
 	"github.com/Dynatrace/dynatrace-operator/src/scheme"
@@ -53,7 +54,9 @@ func (validator *dynakubeValidator) Handle(_ context.Context, request admission.
 	}
 	warningMessages := validator.runValidators(warnings, dynakube)
 	if len(warningMessages) > 0 {
-		warningMessages = append(warningMessages, basePreviewWarning)
+		if hasPreviewWarning(warningMessages) {
+			warningMessages = append(warningMessages, basePreviewWarning)
+		}
 		response = response.WithWarnings(warningMessages...)
 	}
 	return response
@@ -89,3 +92,12 @@ func decodeRequestToDynakube(request admission.Request, dynakube *dynatracev1bet
 	}
 	return nil
 }
+
+func hasPreviewWarning(warnings []string) bool {
+	for _, warning := range warnings {
+		if strings.Contains(warning, "PREVIEW") {
+			return true
+		}
+	}
+	return false
+}

src/webhook/validation/validation_test.go

@@ -60,7 +60,7 @@ var dummyNamespace2 = corev1.Namespace{
 func TestDynakubeValidator_Handle(t *testing.T) {
 	t.Run(`valid dynakube specs`, func(t *testing.T) {
 
-		assertAllowedResponseWithWarnings(t, 3, &dynatracev1beta1.DynaKube{
+		assertAllowedResponseWithWarnings(t, 4, &dynatracev1beta1.DynaKube{
 			ObjectMeta: defaultDynakubeObjectMeta,
 			Spec: dynatracev1beta1.DynaKubeSpec{
 				APIURL: testApiUrl,
@@ -191,12 +191,12 @@ func assertDeniedResponse(t *testing.T, errMessages []string, dynakube *dynatrac
 
 func assertAllowedResponseWithoutWarnings(t *testing.T, dynakube *dynatracev1beta1.DynaKube, other ...client.Object) {
 	response := assertAllowedResponse(t, dynakube, other...)
-	assert.Equal(t, len(response.Warnings), 0)
+	assert.Equal(t, 0, len(response.Warnings))
 }
 
 func assertAllowedResponseWithWarnings(t *testing.T, warningAmount int, dynakube *dynatracev1beta1.DynaKube, other ...client.Object) {
 	response := assertAllowedResponse(t, dynakube, other...)
-	assert.Equal(t, len(response.Warnings), warningAmount)
+	assert.Equal(t, warningAmount, len(response.Warnings))
 }
 
 func assertAllowedResponse(t *testing.T, dynakube *dynatracev1beta1.DynaKube, other ...client.Object) admission.Response {