Merge pull request #71 from dadav/feature_min_max_length

feat: Add MinLength and MaxLength

README.md

@@ -137,6 +137,8 @@ foo: bar
 | [`not`](#not) | A schema that must not be matched. | Takes an `object` |
 | [`if/then/else`](#ifthenelse) | `if` the given schema applies, `then` also apply the given schema or `else` the other schema| Takes an `object` |
 | `$ref` | Accepts a URL to a valid `jsonschema`. Extend the schema for the current key | Takes an URL |
+| [`minLength`](#minlength) | Minimum string length. | Takes an `integer`. Must be smaller or equal than `maxLength` (if used) |
+| [`maxLength`](#maxlength) | Maximum string length. | Takes an `integer`. Must be greater or equal than `minLength` (if used) |
 
 ## Validation & completion
 
@@ -686,6 +688,28 @@ Conditional schema settings with `if`/`then`/`else`
 unknown: foo
 ```
 
+#### `minLength`
+
+The value must be an integer greater or equal to zero and defines the minimum length of a string value.
+
+```yaml
+# @schema
+# minLength: 1
+# @schema
+namespace: foo
+```
+
+#### `maxLength`
+
+The value must be an integer greater than zero and defines the maximum length of a string value.
+
+```yaml
+# @schema
+# maxLength: 3
+# @schema
+namespace: foo
+```
+
 ## License
 
 [MIT](https://github.com/dadav/helm-schema/blob/main/LICENSE)

pkg/schema/schema.go

@@ -219,6 +219,8 @@ type Schema struct {
 	WriteOnly            bool                   `yaml:"writeOnly,omitempty"           json:"writeOnly,omitempty"`
 	Required             BoolOrArrayOfString    `yaml:"required,omitempty"             json:"required,omitempty"`
 	CustomAnnotations    map[string]interface{} `yaml:"-"                              json:",omitempty"`
+	MinLength            *int                   `yaml:"minLength,omitempty"              json:"minLength,omitempty"`
+	MaxLength            *int                   `yaml:"maxLength,omitempty"              json:"maxLength,omitempty"`
 }
 
 func NewSchema(schemaType string) *Schema {
@@ -355,11 +357,16 @@ func (s Schema) Validate() error {
 		return fmt.Errorf("cant use pattern if type is %s. Use type=string", s.Type)
 	}
 
-	// // Check if type=string if format!=""
+	// Check if type=string if format!=""
 	if s.Format != "" && !s.Type.IsEmpty() && !s.Type.Matches("string") {
 		return fmt.Errorf("cant use format if type is %s. Use type=string", s.Type)
 	}
 
+	// Check if type=string if maxLength or minLength is used
+	if s.MaxLength != nil && s.MinLength != nil && *s.MinLength > *s.MaxLength {
+		return errors.New("cant use MinLength > MaxLength")
+	}
+
 	// Cant use Format and Pattern together
 	if s.Format != "" && s.Pattern != "" {
 		return errors.New("cant use format and pattern option at the same time")
@@ -372,7 +379,7 @@ func (s Schema) Validate() error {
 		}
 	}
 
-	// // If type and items are used, type must be array
+	// If type and items are used, type must be array
 	if s.Items != nil && !s.Type.IsEmpty() && !s.Type.Matches("array") {
 		return fmt.Errorf("cant use items if type is %s. Use type=array", s.Type)
 	}

pkg/schema/schema_test.go

@@ -128,6 +128,22 @@ func TestValidate(t *testing.T) {
 			comment: `
 # @schema
 # $ref: https://raw.githubusercontent.com/yannh/kubernetes-json-schema/master/v1.29.2/affinity-v1.json
+# @schema`,
+			expectedValid: true,
+		},
+		{
+			comment: `
+# @schema
+# minLength: 1
+# maxLength: 0
+# @schema`,
+			expectedValid: false,
+		},
+		{
+			comment: `
+# @schema
+# minLength: 1
+# maxLength: 2
 # @schema`,
 			expectedValid: true,
 		},