Merge pull request #30553 from Zhanweelee/add_mustToYaml_support

feat: Add mustToYaml and mustToJson template functions

pkg/engine/funcs.go

@@ -51,10 +51,12 @@ func funcMap() template.FuncMap {
 		"toToml":        toTOML,
 		"fromToml":      fromTOML,
 		"toYaml":        toYAML,
+		"mustToYaml":    mustToYAML,
 		"toYamlPretty":  toYAMLPretty,
 		"fromYaml":      fromYAML,
 		"fromYamlArray": fromYAMLArray,
 		"toJson":        toJSON,
+		"mustToJson":    mustToJSON,
 		"fromJson":      fromJSON,
 		"fromJsonArray": fromJSONArray,
 
@@ -91,6 +93,19 @@ func toYAML(v interface{}) string {
 	return strings.TrimSuffix(string(data), "\n")
 }
 
+// mustToYAML takes an interface, marshals it to yaml, and returns a string.
+// It will panic if there is an error.
+//
+// This is designed to be called from a template when need to ensure that the
+// output YAML is valid.
+func mustToYAML(v interface{}) string {
+	data, err := yaml.Marshal(v)
+	if err != nil {
+		panic(err)
+	}
+	return strings.TrimSuffix(string(data), "\n")
+}
+
 func toYAMLPretty(v interface{}) string {
 	var data bytes.Buffer
 	encoder := goYaml.NewEncoder(&data)
@@ -176,6 +191,19 @@ func toJSON(v interface{}) string {
 	return string(data)
 }
 
+// mustToJSON takes an interface, marshals it to json, and returns a string.
+// It will panic if there is an error.
+//
+// This is designed to be called from a template when need to ensure that the
+// output JSON is valid.
+func mustToJSON(v interface{}) string {
+	data, err := json.Marshal(v)
+	if err != nil {
+		panic(err)
+	}
+	return string(data)
+}
+
 // fromJSON converts a JSON document into a map[string]interface{}.
 //
 // This is not a general-purpose JSON parser, and will not parse all valid

pkg/engine/funcs_test.go

@@ -135,6 +135,43 @@ keyInElement1 = "valueInElement1"`,
 		assert.NoError(t, err)
 		assert.Equal(t, tt.expect, b.String(), tt.tpl)
 	}
+
+	loopMap := map[string]interface{}{
+		"foo": "bar",
+	}
+	loopMap["loop"] = []interface{}{loopMap}
+
+	mustFuncsTests := []struct {
+		tpl    string
+		expect interface{}
+		vars   interface{}
+	}{{
+		tpl:  `{{ mustToYaml . }}`,
+		vars: loopMap,
+	}, {
+		tpl:  `{{ mustToJson . }}`,
+		vars: loopMap,
+	}, {
+		tpl:    `{{ toYaml . }}`,
+		expect: "", // should return empty string and swallow error
+		vars:   loopMap,
+	}, {
+		tpl:    `{{ toJson . }}`,
+		expect: "", // should return empty string and swallow error
+		vars:   loopMap,
+	},
+	}
+
+	for _, tt := range mustFuncsTests {
+		var b strings.Builder
+		err := template.Must(template.New("test").Funcs(funcMap()).Parse(tt.tpl)).Execute(&b, tt.vars)
+		if tt.expect != nil {
+			assert.NoError(t, err)
+			assert.Equal(t, tt.expect, b.String(), tt.tpl)
+		} else {
+			assert.Error(t, err)
+		}
+	}
 }
 
 // This test to check a function provided by sprig is due to a change in a