feat(appset): fromYaml, fromYamlArray toYaml functions (argoproj#15063)

* feat(appset): fromYaml, fromYamlArray toYaml functions

Signed-off-by: Geoffrey Muselli <geoffrey.muselli@gmail.com>

* fix(11993): Document and error messages

Signed-off-by: gmuselli <geoffrey.muselli@gmail.com>

---------

Signed-off-by: Geoffrey Muselli <geoffrey.muselli@gmail.com>
Signed-off-by: gmuselli <geoffrey.muselli@gmail.com>

applicationset/utils/template_functions.go

@@ -0,0 +1,71 @@
+package utils
+
+import (
+	"regexp"
+	"strings"
+
+	"sigs.k8s.io/yaml"
+)
+
+// SanitizeName sanitizes the name in accordance with the below rules
+// 1. contain no more than 253 characters
+// 2. contain only lowercase alphanumeric characters, '-' or '.'
+// 3. start and end with an alphanumeric character
+func SanitizeName(name string) string {
+	invalidDNSNameChars := regexp.MustCompile("[^-a-z0-9.]")
+	maxDNSNameLength := 253
+
+	name = strings.ToLower(name)
+	name = invalidDNSNameChars.ReplaceAllString(name, "-")
+	if len(name) > maxDNSNameLength {
+		name = name[:maxDNSNameLength]
+	}
+
+	return strings.Trim(name, "-.")
+}
+
+// This has been copied from helm and may be removed as soon as it is retrofited in sprig
+// toYAML takes an interface, marshals it to yaml, and returns a string. It will
+// always return a string, even on marshal error (empty string).
+//
+// This is designed to be called from a template.
+func toYAML(v interface{}) (string, error) {
+	data, err := yaml.Marshal(v)
+	if err != nil {
+		// Swallow errors inside of a template.
+		return "", err
+	}
+	return strings.TrimSuffix(string(data), "\n"), nil
+}
+
+// This has been copied from helm and may be removed as soon as it is retrofited in sprig
+// fromYAML converts a YAML document into a map[string]interface{}.
+//
+// This is not a general-purpose YAML parser, and will not parse all valid
+// YAML documents. Additionally, because its intended use is within templates
+// it tolerates errors. It will insert the returned error message string into
+// m["Error"] in the returned map.
+func fromYAML(str string) (map[string]interface{}, error) {
+	m := map[string]interface{}{}
+
+	if err := yaml.Unmarshal([]byte(str), &m); err != nil {
+		return nil, err
+	}
+	return m, nil
+}
+
+// This has been copied from helm and may be removed as soon as it is retrofited in sprig
+// fromYAMLArray converts a YAML array into a []interface{}.
+//
+// This is not a general-purpose YAML parser, and will not parse all valid
+// YAML documents. Additionally, because its intended use is within templates
+// it tolerates errors. It will insert the returned error message string as
+// the first and only item in the returned array.
+func fromYAMLArray(str string) ([]interface{}, error) {
+	a := []interface{}{}
+
+	if err := yaml.Unmarshal([]byte(str), &a); err != nil {
+		return nil, err
+	}
+	return a, nil
+}

applicationset/utils/utils.go

@@ -32,6 +32,9 @@ func init() {
 	delete(sprigFuncMap, "expandenv")
 	delete(sprigFuncMap, "getHostByName")
 	sprigFuncMap["normalize"] = SanitizeName
+	sprigFuncMap["toYaml"] = toYAML
+	sprigFuncMap["fromYaml"] = fromYAML
+	sprigFuncMap["fromYamlArray"] = fromYAMLArray
 }
 
 type Renderer interface {
@@ -431,23 +434,6 @@ func NormalizeBitbucketBasePath(basePath string) string {
 	return basePath
 }
 
-// SanitizeName sanitizes the name in accordance with the below rules
-// 1. contain no more than 253 characters
-// 2. contain only lowercase alphanumeric characters, '-' or '.'
-// 3. start and end with an alphanumeric character
-func SanitizeName(name string) string {
-	invalidDNSNameChars := regexp.MustCompile("[^-a-z0-9.]")
-	maxDNSNameLength := 253
-
-	name = strings.ToLower(name)
-	name = invalidDNSNameChars.ReplaceAllString(name, "-")
-	if len(name) > maxDNSNameLength {
-		name = name[:maxDNSNameLength]
-	}
-
-	return strings.Trim(name, "-.")
-}
-
 func getTlsConfigWithCACert(scmRootCAPath string) *tls.Config {
 
 	tlsConfig := &tls.Config{}

applicationset/utils/utils_test.go

@@ -555,6 +555,64 @@ func TestRenderTemplateParamsGoTemplate(t *testing.T) {
 			templateOptions: []string{"missingkey=error"},
 			errorMessage:    `failed to execute go template --> {{.doesnotexist}} <--: template: :1:6: executing "" at <.doesnotexist>: map has no entry for key "doesnotexist"`,
 		},
+		{
+			name:        "toYaml",
+			fieldVal:    `{{ toYaml . | indent 2 }}`,
+			expectedVal: "  foo:\n    bar:\n      bool: true\n      number: 2\n      str: Hello world",
+			params: map[string]interface{}{
+				"foo": map[string]interface{}{
+					"bar": map[string]interface{}{
+						"bool":   true,
+						"number": 2,
+						"str":    "Hello world",
+					},
+				},
+			},
+		},
+		{
+			name:         "toYaml Error",
+			fieldVal:     `{{ toYaml . | indent 2 }}`,
+			expectedVal:  "  foo:\n    bar:\n      bool: true\n      number: 2\n      str: Hello world",
+			errorMessage: "failed to execute go template {{ toYaml . | indent 2 }}: template: :1:3: executing \"\" at <toYaml .>: error calling toYaml: error marshaling into JSON: json: unsupported type: func(*string)",
+			params: map[string]interface{}{
+				"foo": func(test *string) {
+				},
+			},
+		},
+		{
+			name:        "fromYaml",
+			fieldVal:    `{{ get (fromYaml .value) "hello" }}`,
+			expectedVal: "world",
+			params: map[string]interface{}{
+				"value": "hello: world",
+			},
+		},
+		{
+			name:         "fromYaml error",
+			fieldVal:     `{{ get (fromYaml .value) "hello" }}`,
+			expectedVal:  "world",
+			errorMessage: "failed to execute go template {{ get (fromYaml .value) \"hello\" }}: template: :1:8: executing \"\" at <fromYaml .value>: error calling fromYaml: error unmarshaling JSON: while decoding JSON: json: cannot unmarshal string into Go value of type map[string]interface {}",
+			params: map[string]interface{}{
+				"value": "non\n compliant\n yaml",
+			},
+		},
+		{
+			name:        "fromYamlArray",
+			fieldVal:    `{{ fromYamlArray .value | last }}`,
+			expectedVal: "bonjour tout le monde",
+			params: map[string]interface{}{
+				"value": "- hello world\n- bonjour tout le monde",
+			},
+		},
+		{
+			name:         "fromYamlArray error",
+			fieldVal:     `{{ fromYamlArray .value | last }}`,
+			expectedVal:  "bonjour tout le monde",
+			errorMessage: "failed to execute go template {{ fromYamlArray .value | last }}: template: :1:3: executing \"\" at <fromYamlArray .value>: error calling fromYamlArray: error unmarshaling JSON: while decoding JSON: json: cannot unmarshal string into Go value of type []interface {}",
+			params: map[string]interface{}{
+				"value": "non\n compliant\n yaml",
+			},
+		},
 	}
 
 	for _, test := range tests {

docs/operator-manual/applicationset/GoTemplate.md

@@ -174,6 +174,18 @@ It is also possible to use Sprig functions to construct the path variables manua
 | `{{path.filenameNormalized}}` | `{{.path.filenameNormalized}}` | `{{normalize .path.filename}}` |
 | `{{path[N]}}` | `-` | `{{index .path.segments N}}` |
 
+## Available template functions
+
+ApplicationSet controller provides:
+
+- all [sprig](http://masterminds.github.io/sprig/) Go templates function except `env`, `expandenv` and `getHostByName`
+- `normalize`: sanitizes the input so that it complies with the following rules:
+  1. contains no more than 253 characters
+  2. contains only lowercase alphanumeric characters, '-' or '.'
+  3. starts and ends with an alphanumeric character
+- `toYaml` / `fromYaml` / `fromYamlArray` helm like functions
+
+
 ## Examples
 
 ### Basic Go template usage