fix(11164): Advanced templating using patchTemplate

Signed-off-by: gmuselli <[email protected]>

applicationset/controllers/applicationset_controller.go

@@ -524,6 +524,7 @@ func (r *ApplicationSetReconciler) generateApplications(logCtx *log.Entry, appli
 
 			for _, p := range a.Params {
 				app, err := r.Renderer.RenderTemplateParams(tmplApplication, applicationSetInfo.Spec.SyncPolicy, p, applicationSetInfo.Spec.GoTemplate, applicationSetInfo.Spec.GoTemplateOptions)
+
 				if err != nil {
 					logCtx.WithError(err).WithField("params", a.Params).WithField("generator", requestedGenerator).
 						Error("error generating application from params")
@@ -534,6 +535,24 @@ func (r *ApplicationSetReconciler) generateApplications(logCtx *log.Entry, appli
 					}
 					continue
 				}
+
+				if applicationSetInfo.Spec.TemplatePatch != nil {
+					patchedApplication, err := r.applyTemplatePatch(app, applicationSetInfo, p)
+
+					if err != nil {
+						log.WithError(err).WithField("params", a.Params).WithField("generator", requestedGenerator).
+							Error("error generating application from params")
+
+						if firstError == nil {
+							firstError = err
+							applicationSetReason = argov1alpha1.ApplicationSetReasonRenderTemplateParamsError
+						}
+						continue
+					}
+
+					app = patchedApplication
+				}
+
 				res = append(res, *app)
 			}
 		}
@@ -545,6 +564,16 @@ func (r *ApplicationSetReconciler) generateApplications(logCtx *log.Entry, appli
 	return res, applicationSetReason, firstError
 }
 
+func (r *ApplicationSetReconciler) applyTemplatePatch(app *argov1alpha1.Application, applicationSetInfo argov1alpha1.ApplicationSet, params map[string]interface{}) (*argov1alpha1.Application, error) {
+	replacedTemplate, err := r.Renderer.Replace(*applicationSetInfo.Spec.TemplatePatch, params, applicationSetInfo.Spec.GoTemplate, applicationSetInfo.Spec.GoTemplateOptions)
+
+	if err != nil {
+		return nil, err
+	}
+
+	return utils.ApplyPatchTemplate(app, replacedTemplate)
+}
+
 func ignoreNotAllowedNamespaces(namespaces []string) predicate.Predicate {
 	return predicate.Funcs{
 		CreateFunc: func(e event.CreateEvent) bool {

applicationset/controllers/applicationset_controller_test.go

@@ -86,6 +86,12 @@ func (g *generatorMock) GenerateParams(appSetGenerator *v1alpha1.ApplicationSetG
 	return args.Get(0).([]map[string]interface{}), args.Error(1)
 }
 
+func (g *generatorMock) Replace(tmpl string, replaceMap map[string]interface{}, useGoTemplate bool, goTemplateOptions []string) (string, error) {
+	args := g.Called(tmpl, replaceMap, useGoTemplate, goTemplateOptions)
+
+	return args.Get(0).(string), args.Error(1)
+}
+
 type rendererMock struct {
 	mock.Mock
 }
@@ -107,6 +113,12 @@ func (r *rendererMock) RenderTemplateParams(tmpl *v1alpha1.Application, syncPoli
 
 }
 
+func (r *rendererMock) Replace(tmpl string, replaceMap map[string]interface{}, useGoTemplate bool, goTemplateOptions []string) (string, error) {
+	args := r.Called(tmpl, replaceMap, useGoTemplate, goTemplateOptions)
+
+	return args.Get(0).(string), args.Error(1)
+}
+
 func TestExtractApplications(t *testing.T) {
 	scheme := runtime.NewScheme()
 	err := v1alpha1.AddToScheme(scheme)

applicationset/utils/templatePatch.go

@@ -0,0 +1,42 @@
+package utils
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"k8s.io/apimachinery/pkg/util/strategicpatch"
+
+	appv1 "github.com/argoproj/argo-cd/v2/pkg/apis/application/v1alpha1"
+)
+
+func ApplyPatchTemplate(app *appv1.Application, templatePatch string) (*appv1.Application, error) {
+
+	appString, err := json.Marshal(app)
+	if err != nil {
+		return nil, fmt.Errorf("error while marhsalling Application %w", err)
+	}
+
+	convertedTemplatePatch, err := ConvertYAMLToJSON(templatePatch)
+
+	if err != nil {
+		return nil, fmt.Errorf("error while converting template to json %q: %w", convertedTemplatePatch, err)
+	}
+
+	if err := json.Unmarshal([]byte(convertedTemplatePatch), &appv1.Application{}); err != nil {
+		return nil, fmt.Errorf("invalid templatePatch %q: %w", convertedTemplatePatch, err)
+	}
+
+	data, err := strategicpatch.StrategicMergePatch([]byte(appString), []byte(convertedTemplatePatch), appv1.Application{})
+
+	if err != nil {
+		return nil, fmt.Errorf("error while applying templatePatch template to json %q: %w", convertedTemplatePatch, err)
+	}
+
+	finalApp := appv1.Application{}
+	err = json.Unmarshal(data, &finalApp)
+	if err != nil {
+		return nil, fmt.Errorf("error while unmarhsalling patched application %w", err)
+	}
+
+	return &finalApp, err
+}

applicationset/utils/templatePatch_test.go

@@ -0,0 +1,97 @@
+package utils
+
+import (
+	"testing"
+
+	appv1 "github.com/argoproj/argo-cd/v2/pkg/apis/application/v1alpha1"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+func validate(t *testing.T, patch string) {
+	app := &appv1.Application{
+		TypeMeta: metav1.TypeMeta{
+			Kind:       "Application",
+			APIVersion: "argoproj.io/v1alpha1",
+		},
+		ObjectMeta: metav1.ObjectMeta{
+			Name:       "my-cluster-guestbook",
+			Namespace:  "namespace",
+			Finalizers: []string{"resources-finalizer.argocd.argoproj.io"},
+		},
+		Spec: appv1.ApplicationSpec{
+			Project: "default",
+			Source: &appv1.ApplicationSource{
+				RepoURL:        "https://github.com/argoproj/argocd-example-apps.git",
+				TargetRevision: "HEAD",
+				Path:           "guestbook",
+			},
+			Destination: appv1.ApplicationDestination{
+				Server:    "https://kubernetes.default.svc",
+				Namespace: "guestbook",
+			},
+		},
+	}
+
+	result, err := ApplyPatchTemplate(app, patch)
+	require.NoError(t, err)
+	require.Contains(t, result.ObjectMeta.Annotations, "annotation-some-key")
+	assert.Equal(t, result.ObjectMeta.Annotations["annotation-some-key"], "annotation-some-value")
+
+	assert.Equal(t, result.Spec.SyncPolicy.Automated.Prune, true)
+	require.Contains(t, result.Spec.Source.Helm.ValueFiles, "values.test.yaml")
+	require.Contains(t, result.Spec.Source.Helm.ValueFiles, "values.big.yaml")
+}
+
+func TestWithJson(t *testing.T) {
+
+	validate(t, `{
+		"metadata": {
+			"annotations": {
+				"annotation-some-key": "annotation-some-value"
+			}
+		},
+		"spec": {
+			"source": {
+				"helm": {
+					"valueFiles": [
+						"values.test.yaml",
+						"values.big.yaml"
+					]
+				}
+			},
+			"syncPolicy": {
+				"automated": {
+					"prune": true
+				}
+			}
+		}
+	}`)
+
+}
+
+func TestWithYaml(t *testing.T) {
+
+	validate(t, `
+metadata:
+  annotations:
+    annotation-some-key: annotation-some-value
+spec:
+  source:
+    helm:
+      valueFiles:
+        - values.test.yaml
+        - values.big.yaml
+  syncPolicy:
+    automated:
+      prune: true`)
+}
+
+func TestError(t *testing.T) {
+	app := &appv1.Application{}
+
+	result, err := ApplyPatchTemplate(app, "hello world")
+	require.Error(t, err)
+	require.Nil(t, result)
+}

applicationset/utils/utils.go

@@ -41,6 +41,7 @@ func init() {
 
 type Renderer interface {
 	RenderTemplateParams(tmpl *argoappsv1.Application, syncPolicy *argoappsv1.ApplicationSetSyncPolicy, params map[string]interface{}, useGoTemplate bool, goTemplateOptions []string) (*argoappsv1.Application, error)
+	Replace(tmpl string, replaceMap map[string]interface{}, useGoTemplate bool, goTemplateOptions []string) (string, error)
 }
 
 type Render struct {

assets/swagger.json

@@ -6143,6 +6143,9 @@
         },
         "template": {
           "$ref": "#/definitions/v1alpha1ApplicationSetTemplate"
+        },
+        "templatePatch": {
+          "type": "string"
         }
       }
     },

docs/operator-manual/applicationset/Template.md

@@ -108,3 +108,60 @@ spec:
 (*The full example can be found [here](https://github.com/argoproj/argo-cd/tree/master/applicationset/examples/template-override).*)
 
 In this example, the ApplicationSet controller will generate an `Application` resource using the `path` generated by the List generator, rather than the `path` value defined in `.spec.template`.
+
+## Patch Template
+
+Templating is only available on string type. However some uses cases may require to apply templating on other types.
+
+Example:
+
+- Set the automated sync policy
+- Switch prune boolean to true
+- Add multiple helm value files
+
+ArgoCD has a `templatePatch` feature to allow advanced templating. It supports both json and yaml
+
+
+```yaml
+apiVersion: argoproj.io/v1alpha1
+kind: ApplicationSet
+metadata:
+  name: guestbook
+spec:
+  goTemplate: true
+  generators:
+  - list:
+      elements:
+        - cluster: engineering-dev
+          url: https://kubernetes.default.svc
+          autoSync: true
+          prune: true
+          valueFiles:
+            - values.large.yaml
+            - values.debug.yaml
+  templatePatch: |
+    spec:
+      source:
+        helm:
+          valueFiles:
+          {{- range $valueFile := .valueFiles }}
+            - {{ $valueFile }}
+          {{- end }}
+    {{- if .autoSync }}
+      syncPolicy:
+        automated:
+          prune: {{ .prune }}
+    {{- end }}
+  template:
+    metadata:
+      name: '{{.cluster}}-deployment'
+    spec:
+      project: "default"
+      source:
+        repoURL: https://github.com/infra-team/cluster-deployments.git
+        targetRevision: HEAD
+        path: guestbook/{{ .cluster }}
+      destination:
+        server: '{{.url}}'
+        namespace: guestbook
+```

manifests/core-install.yaml

@@ -20123,6 +20123,8 @@ spec:
                 - metadata
                 - spec
                 type: object
+              templatePatch:
+                type: string
             required:
             - generators
             - template

manifests/crds/applicationset-crd.yaml

@@ -15183,6 +15183,8 @@ spec:
                 - metadata
                 - spec
                 type: object
+              templatePatch:
+                type: string
             required:
             - generators
             - template

manifests/ha/install.yaml

@@ -20123,6 +20123,8 @@ spec:
                 - metadata
                 - spec
                 type: object
+              templatePatch:
+                type: string
             required:
             - generators
             - template

manifests/install.yaml

@@ -20123,6 +20123,8 @@ spec:
                 - metadata
                 - spec
                 type: object
+              templatePatch:
+                type: string
             required:
             - generators
             - template

pkg/apis/application/v1alpha1/applicationset_types.go

@@ -65,6 +65,7 @@ type ApplicationSetSpec struct {
 	// ApplyNestedSelectors enables selectors defined within the generators of two level-nested matrix or merge generators
 	ApplyNestedSelectors         bool                            `json:"applyNestedSelectors,omitempty" protobuf:"bytes,8,name=applyNestedSelectors"`
 	IgnoreApplicationDifferences ApplicationSetIgnoreDifferences `json:"ignoreApplicationDifferences,omitempty" protobuf:"bytes,9,name=ignoreApplicationDifferences"`
+	TemplatePatch                *string                         `json:"templatePatch,omitempty" protobuf:"bytes,10,name=templatePatch"`
 }
 
 type ApplicationPreservedFields struct {