Generate template placeholders for env vars and images in charts

pkg/app/app.go

@@ -261,7 +261,7 @@ func Convert(opt kobject.ConvertOptions) ([]runtime.Object, error) {
 	}
 
 	// Print output
-	err = kubernetes.PrintList(objects, opt)
+	err = kubernetes.PrintList(objects, opt, komposeObject)
 	if err != nil {
 		log.Fatalf(err.Error())
 	}

pkg/transformer/kubernetes/k8sutils.go

@@ -82,10 +82,157 @@ type DeploymentMapping struct {
 	TargetDeploymentName string
 }
 
+// ServiceValues holds the extracted values for templating
+type ServiceValues struct {
+	Image struct {
+		Repository string
+		Tag        string
+		PullPolicy string
+	}
+	Env map[string]string
+}
+
+// splitImage splits "repo:tag" or "repo" into repository and tag
+func splitImage(image string) (string, string) {
+	parts := strings.Split(image, ":")
+	if len(parts) == 2 {
+		return parts[0], parts[1]
+	}
+	// No tag specified, use "latest"
+	return image, "latest"
+}
+
+// extractImageValues extracts image information from Deployment and StatefulSet objects
+func extractImageValues(objects []runtime.Object) map[string]ServiceValues {
+	values := make(map[string]ServiceValues)
+
+	for _, obj := range objects {
+		switch o := obj.(type) {
+		case *appsv1.Deployment:
+			serviceName := o.ObjectMeta.Name
+			if len(o.Spec.Template.Spec.Containers) > 0 {
+				container := o.Spec.Template.Spec.Containers[0]
+
+				repo, tag := splitImage(container.Image)
+				pullPolicy := string(container.ImagePullPolicy)
+				if pullPolicy == "" {
+					pullPolicy = "IfNotPresent"
+				}
+
+				svcValues := ServiceValues{}
+				svcValues.Image.Repository = repo
+				svcValues.Image.Tag = tag
+				svcValues.Image.PullPolicy = pullPolicy
+
+				// Extract env vars
+				svcValues.Env = make(map[string]string)
+				for _, envVar := range container.Env {
+					svcValues.Env[envVar.Name] = envVar.Value
+				}
+
+				values[serviceName] = svcValues
+			}
+
+		case *appsv1.StatefulSet:
+			serviceName := o.ObjectMeta.Name
+			if len(o.Spec.Template.Spec.Containers) > 0 {
+				container := o.Spec.Template.Spec.Containers[0]
+
+				repo, tag := splitImage(container.Image)
+				pullPolicy := string(container.ImagePullPolicy)
+				if pullPolicy == "" {
+					pullPolicy = "IfNotPresent"
+				}
+
+				svcValues := ServiceValues{}
+				svcValues.Image.Repository = repo
+				svcValues.Image.Tag = tag
+				svcValues.Image.PullPolicy = pullPolicy
+
+				// Extract env vars
+				svcValues.Env = make(map[string]string)
+				for _, envVar := range container.Env {
+					svcValues.Env[envVar.Name] = envVar.Value
+				}
+
+				values[serviceName] = svcValues
+			}
+		}
+	}
+
+	return values
+}
+
+// templatizeImage replaces image and imagePullPolicy with Helm template syntax
+func templatizeImage(yamlBytes []byte, serviceName string, values map[string]ServiceValues) []byte {
+	if svcValues, ok := values[serviceName]; ok {
+		yamlStr := string(yamlBytes)
+
+		// Replace image line
+		originalImage := svcValues.Image.Repository + ":" + svcValues.Image.Tag
+		templatedImage := "{{ .Values." + serviceName + ".image.repository }}:{{ .Values." + serviceName + ".image.tag }}"
+		yamlStr = strings.Replace(yamlStr, "image: "+originalImage, "image: "+templatedImage, 1)
+
+		// Replace imagePullPolicy line
+		if svcValues.Image.PullPolicy != "" {
+			originalPolicy := "imagePullPolicy: " + svcValues.Image.PullPolicy
+			templatedPolicy := "imagePullPolicy: {{ .Values." + serviceName + ".image.pullPolicy }}"
+			yamlStr = strings.Replace(yamlStr, originalPolicy, templatedPolicy, 1)
+		}
+
+		return []byte(yamlStr)
+	}
+	return yamlBytes
+}
+
+// templatizeEnv replaces env var values with Helm template syntax
+func templatizeEnv(yamlBytes []byte, serviceName string, values map[string]ServiceValues) []byte {
+	if svcValues, ok := values[serviceName]; ok {
+		yamlStr := string(yamlBytes)
+
+		for envName, envValue := range svcValues.Env {
+			template := "{{ .Values." + serviceName + ".env." + envName + " | quote }}"
+
+			if envValue != "" {
+				// Match: name: ENVNAME\n<spaces>value: "VALUE" or value: VALUE
+				// Replace with: name: ENVNAME\n<spaces>value: TEMPLATE
+				pattern := `(name: ` + regexp.QuoteMeta(envName) + `)\n(\s+)value: (?:"` + regexp.QuoteMeta(envValue) + `"|` + regexp.QuoteMeta(envValue) + `)`
+				replacement := `${1}` + "\n" + `${2}value: ` + template
+				re := regexp.MustCompile(pattern)
+				yamlStr = re.ReplaceAllString(yamlStr, replacement)
+			} else {
+				// For empty values, handle two cases:
+				// 1. name: ENVNAME\n<spaces>value: ""
+				// 2. name: ENVNAME\n      - name: (no value field)
+
+				// Try to replace existing empty value first
+				pattern1 := `(name: ` + regexp.QuoteMeta(envName) + `)\n(\s+)value: ""`
+				replacement1 := `${1}` + "\n" + `${2}value: ` + template
+				re1 := regexp.MustCompile(pattern1)
+				newYamlStr := re1.ReplaceAllString(yamlStr, replacement1)
+
+				// If nothing was replaced, insert value field after name
+				if newYamlStr == yamlStr {
+					// Match the current list item with its indentation
+					pattern2 := `(\s+)- (name: ` + regexp.QuoteMeta(envName) + `)\n`
+					replacement2 := "${1}- ${2}${1}  value: " + template + "\n"
+					re2 := regexp.MustCompile(pattern2)
+					yamlStr = re2.ReplaceAllString(yamlStr, replacement2)
+				} else {
+					yamlStr = newYamlStr
+				}
+			}
+		}
+
+		return []byte(yamlStr)
+	}
+	return yamlBytes
+}
+
 /**
  * Generate Helm Chart configuration
  */
-func generateHelm(dirName string) error {
+func generateHelm(dirName string, values map[string]ServiceValues) error {
 	type ChartDetails struct {
 		Name string
 	}
@@ -141,10 +288,61 @@ home:
 		return err
 	}
 
+	/* Create the values.yaml file */
+	if len(values) > 0 {
+		valuesYAML, err := generateValuesYAML(values)
+		if err != nil {
+			return errors.Wrap(err, "Failed to generate values.yaml")
+		}
+		err = os.WriteFile(dirName+string(os.PathSeparator)+"values.yaml", valuesYAML, 0644)
+		if err != nil {
+			return err
+		}
+	}
+
 	log.Infof("chart created in %q\n", dirName+string(os.PathSeparator))
 	return nil
 }
 
+// generateValuesYAML creates values.yaml content from extracted values
+func generateValuesYAML(values map[string]ServiceValues) ([]byte, error) {
+	// Build hierarchical structure: serviceName -> image -> {repository, tag, pullPolicy}
+	valuesMap := make(map[string]interface{})
+
+	// Sort service names for consistent output
+	serviceNames := make([]string, 0, len(values))
+	for name := range values {
+		serviceNames = append(serviceNames, name)
+	}
+	sort.Strings(serviceNames)
+
+	for _, serviceName := range serviceNames {
+		svcValues := values[serviceName]
+		serviceMap := map[string]interface{}{
+			"image": map[string]string{
+				"repository": svcValues.Image.Repository,
+				"tag":        svcValues.Image.Tag,
+				"pullPolicy": svcValues.Image.PullPolicy,
+			},
+		}
+
+		// Add env vars if present
+		if len(svcValues.Env) > 0 {
+			serviceMap["env"] = svcValues.Env
+		}
+
+		valuesMap[serviceName] = serviceMap
+	}
+
+	// Use marshalWithIndent for consistent 2-space indentation
+	yamlBytes, err := marshalWithIndent(valuesMap, 2)
+	if err != nil {
+		return nil, err
+	}
+
+	return yamlBytes, nil
+}
+
 // Check if given path is a directory
 func isDir(name string) (bool, error) {
 	// Open file to get stat later
@@ -183,7 +381,7 @@ func getDirName(opt kobject.ConvertOptions) string {
 }
 
 // PrintList will take the data converted and decide on the commandline attributes given
-func PrintList(objects []runtime.Object, opt kobject.ConvertOptions) error {
+func PrintList(objects []runtime.Object, opt kobject.ConvertOptions, komposeObject kobject.KomposeObject) error {
 	var f *os.File
 	dirName := getDirName(opt)
 	log.Debugf("Target Dir: %s", dirName)
@@ -215,6 +413,13 @@ func PrintList(objects []runtime.Object, opt kobject.ConvertOptions) error {
 	}
 
 	var files []string
+	var imageValues map[string]ServiceValues
+
+	// Extract image values for chart templating (before processing)
+	if opt.CreateChart {
+		imageValues = extractImageValues(objects)
+	}
+
 	// if asked to print to stdout or to put in single file
 	// we will create a list
 	if opt.ToStdout || f != nil {
@@ -265,6 +470,7 @@ func PrintList(objects []runtime.Object, opt kobject.ConvertOptions) error {
 			var typeMeta metav1.TypeMeta
 			var objectMeta metav1.ObjectMeta
 
+			// Get object metadata first for templating
 			if us, ok := v.(*unstructured.Unstructured); ok {
 				typeMeta = metav1.TypeMeta{
 					Kind:       us.GetKind(),
@@ -275,15 +481,16 @@ func PrintList(objects []runtime.Object, opt kobject.ConvertOptions) error {
 				}
 			} else {
 				val := reflect.ValueOf(v).Elem()
-				// Use reflect to access TypeMeta struct inside runtime.Object.
-				// cast it to correct type - metav1.TypeMeta
 				typeMeta = val.FieldByName("TypeMeta").Interface().(metav1.TypeMeta)
-
-				// Use reflect to access ObjectMeta struct inside runtime.Object.
-				// cast it to correct type - api.ObjectMeta
 				objectMeta = val.FieldByName("ObjectMeta").Interface().(metav1.ObjectMeta)
 			}
 
+			// Templatize YAML if generating chart
+			if opt.CreateChart && imageValues != nil {
+				data = templatizeEnv(data, objectMeta.Name, imageValues)
+				data = templatizeImage(data, objectMeta.Name, imageValues)
+			}
+
 			file, err = transformer.Print(objectMeta.Name, finalDirName, strings.ToLower(typeMeta.Kind), data, opt.ToStdout, opt.GenerateJSON, f, opt.Provider)
 			if err != nil {
 				return errors.Wrap(err, "transformer.Print failed")
@@ -293,7 +500,7 @@ func PrintList(objects []runtime.Object, opt kobject.ConvertOptions) error {
 		}
 	}
 	if opt.CreateChart {
-		err = generateHelm(dirName)
+		err = generateHelm(dirName, imageValues)
 		if err != nil {
 			return errors.Wrap(err, "generateHelm failed")
 		}