feat: support K8S json patch (#4908)

Signed-off-by: book987 <book78987book@gmail.com>

test/e2e/functional/k8s-patch.yaml

@@ -0,0 +1,20 @@
+apiVersion: argoproj.io/v1alpha1
+kind: Workflow
+metadata:
+  generateName: k8s-patch-
+  labels:
+    argo-e2e: "true"
+spec:
+  entrypoint: patch-pod
+  templates:
+  - name: patch-pod
+    resource:
+      action: patch
+      mergeStrategy: json
+      flags:
+      - pods
+      - "{{pod.name}}"
+      manifest: |
+        - op: add
+          path: /metadata/annotations/foo
+          value: bar

test/e2e/functional_test.go

@@ -1028,6 +1028,18 @@ spec:
 		})
 }
 
+func (s *FunctionalSuite) TestK8SJSONPatch() {
+	s.Given().
+		Workflow("@functional/k8s-patch.yaml").
+		When().
+		SubmitWorkflow().
+		WaitForWorkflow().
+		Then().
+		ExpectWorkflow(func(t *testing.T, metadata *metav1.ObjectMeta, status *wfv1.WorkflowStatus) {
+			assert.Equal(t, wfv1.WorkflowSucceeded, status.Phase)
+		})
+}
+
 func TestFunctionalSuite(t *testing.T) {
 	suite.Run(t, new(FunctionalSuite))
 }

workflow/controller/operator.go

@@ -2658,14 +2658,13 @@ func (woc *wfOperationCtx) executeResource(ctx context.Context, nodeName string,
 
 	tmpl = tmpl.DeepCopy()
 
-	// Try to unmarshal the given manifest.
-	obj := unstructured.Unstructured{}
-	err := yaml.Unmarshal([]byte(tmpl.Resource.Manifest), &obj)
-	if err != nil {
-		return node, err
-	}
-
 	if tmpl.Resource.SetOwnerReference {
+		obj := unstructured.Unstructured{}
+		err := yaml.Unmarshal([]byte(tmpl.Resource.Manifest), &obj)
+		if err != nil {
+			return node, err
+		}
+
 		ownerReferences := obj.GetOwnerReferences()
 		obj.SetOwnerReferences(append(ownerReferences, *metav1.NewControllerRef(woc.wf, wfv1.SchemeGroupVersion.WithKind(workflow.WorkflowKind))))
 		bytes, err := yaml.Marshal(obj.Object)
@@ -2677,7 +2676,7 @@ func (woc *wfOperationCtx) executeResource(ctx context.Context, nodeName string,
 
 	mainCtr := woc.newExecContainer(common.MainContainerName, tmpl)
 	mainCtr.Command = []string{"argoexec", "resource", tmpl.Resource.Action}
-	_, err = woc.createWorkflowPod(ctx, nodeName, *mainCtr, tmpl, &createWorkflowPodOpts{onExitPod: opts.onExitTemplate, executionDeadline: opts.executionDeadline})
+	_, err := woc.createWorkflowPod(ctx, nodeName, *mainCtr, tmpl, &createWorkflowPodOpts{onExitPod: opts.onExitTemplate, executionDeadline: opts.executionDeadline})
 	if err != nil {
 		return woc.requeueIfTransientErr(err, node.Name)
 	}

workflow/executor/resource.go

@@ -90,7 +90,10 @@ func (we *WorkflowExecutor) getKubectlArguments(action string, manifestPath stri
 		args = append(args, flags...)
 	}
 
-	if len(buff) != 0 {
+	// Action "patch" require flag "-p" with resource arguments.
+	// But kubectl disallow specify both "-f" flag and resource arguments.
+	// Flag "-f" should be excluded for action "patch" here.
+	if len(buff) != 0 && action != "patch" {
 		args = append(args, "-f")
 		args = append(args, manifestPath)
 	} else if len(flags) <= 0 {

workflow/validate/validate.go

@@ -14,7 +14,6 @@ import (
 	"github.com/sirupsen/logrus"
 	"github.com/valyala/fasttemplate"
 	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	apivalidation "k8s.io/apimachinery/pkg/util/validation"
 	"sigs.k8s.io/yaml"
 
@@ -692,8 +691,8 @@ func (ctx *templateValidationCtx) validateLeaf(scope map[string]interface{}, tmp
 			}
 		}
 		if !placeholderGenerator.IsPlaceholder(tmpl.Resource.Manifest) {
-			// Try to unmarshal the given manifest.
-			obj := unstructured.Unstructured{}
+			// Try to unmarshal the given manifest, just ensuring it's a valid YAML.
+			var obj interface{}
 			err := yaml.Unmarshal([]byte(tmpl.Resource.Manifest), &obj)
 			if err != nil {
 				return errors.Errorf(errors.CodeBadRequest, "templates.%s.resource.manifest must be a valid yaml", tmpl.Name)