feat: 3 ways merge base on json merge patch

pkg/engine/runtime/kubernetest_runtime.go

@@ -4,21 +4,21 @@ import (
 	"context"
 	"errors"
 
-	"kusionstack.io/kusion/pkg/engine/models"
-
 	k8serrors "k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/api/meta"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	k8syaml "k8s.io/apimachinery/pkg/runtime/serializer/yaml"
 	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/apimachinery/pkg/util/jsonmergepatch"
 	"k8s.io/client-go/discovery"
 	memory "k8s.io/client-go/discovery/cached"
 	"k8s.io/client-go/dynamic"
 	"k8s.io/client-go/restmapper"
 	"k8s.io/client-go/tools/clientcmd"
 
+	"kusionstack.io/kusion/pkg/engine/models"
 	"kusionstack.io/kusion/pkg/log"
 	"kusionstack.io/kusion/pkg/status"
 	"kusionstack.io/kusion/pkg/util/kube/config"
@@ -52,51 +52,39 @@ func (k *KubernetesRuntime) Apply(ctx context.Context, priorState, planState *mo
 		return nil, status.NewErrorStatus(errors.New("plan state is nil"))
 	}
 
-	// Get kubernetes resource from plan state
-	obj, resource, err := k.buildKubernetesResourceByState(planState)
+	// Get kubernetes resource interface from plan state
+	planObj, resource, err := k.buildKubernetesResourceByState(planState)
 	if err != nil {
 		return nil, status.NewErrorStatus(err)
 	}
 
-	// Create or Update resource
-	if priorState == nil {
-		// Create
-		if _, err = resource.Get(ctx, obj.GetName(), metav1.GetOptions{}); err != nil {
-			// Create the resource if not exists
-			if !k8serrors.IsNotFound(err) {
-				return nil, status.NewErrorStatus(err)
-			}
-
-			log.Infof("Create the resource %s/%s/%s because it doesn't exist", obj.GetKind(), obj.GetNamespace(), obj.GetName())
-			_, err = resource.Create(ctx, obj, metav1.CreateOptions{})
-		} else {
-			// Patch the resource because already exists
-			log.Infof("Patch the resource %s/%s/%s because it already exists", obj.GetKind(), obj.GetNamespace(), obj.GetName())
-
-			var objJSON []byte
-			objJSON, err = obj.MarshalJSON()
-			if err != nil {
-				return nil, status.NewErrorStatus(err)
-			}
-
-			_, err = resource.Patch(ctx, obj.GetName(), types.MergePatchType, objJSON, metav1.PatchOptions{
-				FieldManager: "kusion",
-			})
-		}
-	} else {
-		// Update
-		_, err = resource.Update(ctx, obj, metav1.UpdateOptions{
-			FieldManager: "kusion",
-		})
+	// original equals to last-applied from annotation, kusion store it in kusion_state.json
+	original := yaml.MergeToOneYAML(priorState.Attributes)
+	// modified equals input content
+	modified := yaml.MergeToOneYAML(planState.Attributes)
+	// live config
+	liveObj, err := resource.Get(ctx, planObj.GetName(), metav1.GetOptions{})
+	if err != nil {
+		return nil, status.NewErrorStatus(err)
 	}
 
+	current := yaml.MergeToOneYAML(liveObj.Object)
+	// 3-way json merge patch
+	patch, err := jsonmergepatch.CreateThreeWayJSONMergePatch([]byte(original), []byte(modified), []byte(current))
+	if err != nil {
+		return nil, status.NewErrorStatus(err)
+	}
+	// apply patch
+	patchedObj, err := resource.Patch(ctx, planObj.GetName(), types.MergePatchType, patch, metav1.PatchOptions{
+		FieldManager: "kusion",
+	})
 	if err != nil {
 		return nil, status.NewErrorStatus(err)
 	}
 
 	return &models.Resource{
 		ID:         planState.ResourceKey(),
-		Attributes: obj.Object,
+		Attributes: patchedObj.Object,
 		DependsOn:  planState.DependsOn,
 	}, nil
 }