Render templates with options

Signed-off-by: Raul Sevilla <rsevilla@redhat.com>

pkg/burner/create.go

@@ -72,7 +72,7 @@ func setupCreateJob(jobConfig config.Job) Executor {
 		}
 		// Deserialize YAML
 		uns := &unstructured.Unstructured{}
-		renderedObj := renderTemplate(t, empty)
+		renderedObj := renderTemplate(t, empty, missingKeyDefault)
 		_, gvk := yamlToUnstructured(renderedObj, uns)
 		gvr, _ := meta.UnsafeGuessKindToResource(*gvk)
 		obj := object{
@@ -152,18 +152,18 @@ func (ex *Executor) replicaHandler(objectIndex int, obj object, ns string, itera
 		"kube-burner-job":   ex.Config.Name,
 		"kube-burner-index": strconv.Itoa(objectIndex),
 	}
-	tData := map[string]interface{}{
+	templateData := map[string]interface{}{
 		jobName:      ex.Config.Name,
 		jobIteration: iteration,
 		jobUUID:      ex.uuid,
 	}
 	for k, v := range obj.inputVars {
-		tData[k] = v
+		templateData[k] = v
 	}
 	for r := 1; r <= obj.replicas; r++ {
 		newObject := &unstructured.Unstructured{}
-		tData[replica] = r
-		renderedObj := renderTemplate(obj.objectSpec, tData)
+		templateData[replica] = r
+		renderedObj := renderTemplate(obj.objectSpec, templateData, missingKeyError)
 		// Re-decode rendered object
 		yamlToUnstructured(renderedObj, newObject)
 		for k, v := range newObject.GetLabels() {

pkg/burner/utils.go

@@ -30,17 +30,21 @@ import (
 	"k8s.io/kubectl/pkg/scheme"
 )
 
+type templateOption string
+
 const (
 	// Parameters for retrying with exponential backoff.
-	retryBackoffInitialDuration = 1 * time.Second
-	retryBackoffFactor          = 3
-	retryBackoffJitter          = 0
-	retryBackoffSteps           = 3
+	retryBackoffInitialDuration                = 1 * time.Second
+	retryBackoffFactor                         = 3
+	retryBackoffJitter                         = 0
+	retryBackoffSteps                          = 3
+	missingKeyDefault           templateOption = "missingkey=default"
+	missingKeyError             templateOption = "missingkey=error"
 )
 
-func renderTemplate(original []byte, data interface{}) []byte {
+func renderTemplate(original []byte, data interface{}, options templateOption) []byte {
 	var rendered bytes.Buffer
-	t, err := template.New("").Parse(string(original))
+	t, err := template.New("").Option(string(options)).Parse(string(original))
 	if err != nil {
 		log.Fatalf("Error parsing template: %s", err)
 	}