From 7163d723351718fcdd666acc3c4a707f1f7fcfb1 Mon Sep 17 00:00:00 2001
From: Rui Vieira <ruidevieira@googlemail.com>
Date: Thu, 10 Oct 2024 16:02:17 +0100
Subject: [PATCH] Add check for DestinationRule CRD

---
 controllers/destination_rule.go   | 20 ++++++++++++++++++++
 controllers/inference_services.go | 20 ++++++++++++++++++--
 2 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/controllers/destination_rule.go b/controllers/destination_rule.go
index f683373e..ce17552f 100644
--- a/controllers/destination_rule.go
+++ b/controllers/destination_rule.go
@@ -7,6 +7,7 @@ import (
 
 	trustyaiopendatahubiov1alpha1 "github.com/trustyai-explainability/trustyai-service-operator/api/v1alpha1"
 	templateParser "github.com/trustyai-explainability/trustyai-service-operator/controllers/templates"
+	apiextensionsv1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
 	"k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/types"
@@ -16,6 +17,7 @@ import (
 
 const (
 	destinationRuleTemplatePath = "service/destination-rule.tmpl.yaml"
+	destinationRuleCDRName      = "destinationrules.networking.istio.io"
 )
 
 // DestinationRuleConfig has the variables for the DestinationRule template
@@ -25,7 +27,25 @@ type DestinationRuleConfig struct {
 	DestinationRuleName string
 }
 
+// isDestinationRuleCRDPresent returns true if the DestinationRule CRD is present, false otherwise
+func (r *TrustyAIServiceReconciler) isDestinationRuleCRDPresent(ctx context.Context) (bool, error) {
+	crd := &apiextensionsv1.CustomResourceDefinition{}
+
+	err := r.Get(ctx, types.NamespacedName{Name: destinationRuleCDRName}, crd)
+	if err != nil {
+		if !errors.IsNotFound(err) {
+			return false, fmt.Errorf("error getting "+destinationRuleCDRName+" CRD: %v", err)
+		}
+		// Not found
+		return false, nil
+	}
+
+	// Found
+	return true, nil
+}
+
 func (r *TrustyAIServiceReconciler) ensureDestinationRule(ctx context.Context, instance *trustyaiopendatahubiov1alpha1.TrustyAIService) error {
+
 	destinationRuleName := instance.Name + "-internal"
 
 	existingDestinationRule := &unstructured.Unstructured{}
diff --git a/controllers/inference_services.go b/controllers/inference_services.go
index a4cad7be..ee8745bf 100644
--- a/controllers/inference_services.go
+++ b/controllers/inference_services.go
@@ -275,10 +275,26 @@ func (r *TrustyAIServiceReconciler) patchKServe(ctx context.Context, instance *t
 	// Only if the Istio sidecar annotation is set
 	annotations := infService.GetAnnotations()
 	if inject, exists := annotations["sidecar.istio.io/inject"]; exists && inject == "true" {
-		err := r.ensureDestinationRule(ctx, instance)
+
+		// Check if DestinationRule CRD is present. If there's an error, don't proceed and return the error
+		exists, err := r.isDestinationRuleCRDPresent(ctx)
 		if err != nil {
-			return fmt.Errorf("failed to ensure DestinationRule: %v", err)
+			log.FromContext(ctx).Error(err, "Error verifying DestinationRule CRD is present")
+			return err
+		}
+
+		// Try to create the DestinationRule, since CRD exists
+		if exists {
+			err := r.ensureDestinationRule(ctx, instance)
+			if err != nil {
+				return fmt.Errorf("failed to ensure DestinationRule: %v", err)
+			}
+		} else {
+			// DestinationRule CRD does not exist. Do not attempt to create it and log error
+			err := fmt.Errorf("the DestinationRule CRD is not present in this cluster")
+			log.FromContext(ctx).Error(err, "InferenceService has service mesh annotation but DestinationRule CRD not found")
 		}
+
 	}
 
 	// Update the InferenceService