Add TypeLowerCaseString (#4683)

logical/framework/backend.go

@@ -530,9 +530,7 @@ func (s *FieldSchema) DefaultOrZero() interface{} {
 // Zero returns the correct zero-value for a specific FieldType
 func (t FieldType) Zero() interface{} {
 	switch t {
-	case TypeNameString:
+	case TypeString, TypeNameString, TypeLowerCaseString:
-		return ""
-	case TypeString:
 		return ""
 	case TypeInt:
 		return 0

logical/framework/field_data.go

@@ -35,7 +35,7 @@ func (d *FieldData) Validate() error {
 		}
 
 		switch schema.Type {
-		case TypeBool, TypeInt, TypeMap, TypeDurationSecond, TypeString,
+		case TypeBool, TypeInt, TypeMap, TypeDurationSecond, TypeString, TypeLowerCaseString,
 			TypeNameString, TypeSlice, TypeStringSlice, TypeCommaStringSlice,
 			TypeKVPairs, TypeCommaIntSlice:
 			_, _, err := d.getPrimitive(field, schema)
@@ -111,7 +111,7 @@ func (d *FieldData) GetOkErr(k string) (interface{}, bool, error) {
 	}
 
 	switch schema.Type {
-	case TypeBool, TypeInt, TypeMap, TypeDurationSecond, TypeString,
+	case TypeBool, TypeInt, TypeMap, TypeDurationSecond, TypeString, TypeLowerCaseString,
 		TypeNameString, TypeSlice, TypeStringSlice, TypeCommaStringSlice,
 		TypeKVPairs, TypeCommaIntSlice:
 		return d.getPrimitive(k, schema)
@@ -149,6 +149,13 @@ func (d *FieldData) getPrimitive(k string, schema *FieldSchema) (interface{}, bo
 		}
 		return result, true, nil
 
+	case TypeLowerCaseString:
+		var result string
+		if err := mapstructure.WeakDecode(raw, &result); err != nil {
+			return nil, true, err
+		}
+		return strings.ToLower(result), true, nil
+
 	case TypeNameString:
 		var result string
 		if err := mapstructure.WeakDecode(raw, &result); err != nil {

logical/framework/field_data_test.go

@@ -55,6 +55,60 @@ func TestFieldDataGet(t *testing.T) {
 			"bar",
 		},
 
+		"lowercase string type, lowercase string value": {
+			map[string]*FieldSchema{
+				"foo": &FieldSchema{Type: TypeLowerCaseString},
+			},
+			map[string]interface{}{
+				"foo": "bar",
+			},
+			"foo",
+			"bar",
+		},
+
+		"lowercase string type, mixed-case string value": {
+			map[string]*FieldSchema{
+				"foo": &FieldSchema{Type: TypeLowerCaseString},
+			},
+			map[string]interface{}{
+				"foo": "BaR",
+			},
+			"foo",
+			"bar",
+		},
+
+		"lowercase string type, int value": {
+			map[string]*FieldSchema{
+				"foo": &FieldSchema{Type: TypeLowerCaseString},
+			},
+			map[string]interface{}{
+				"foo": 42,
+			},
+			"foo",
+			"42",
+		},
+
+		"lowercase string type, unset value": {
+			map[string]*FieldSchema{
+				"foo": &FieldSchema{Type: TypeLowerCaseString},
+			},
+			map[string]interface{}{},
+			"foo",
+			"",
+		},
+
+		"lowercase string type, unset value with lowercase default": {
+			map[string]*FieldSchema{
+				"foo": &FieldSchema{
+					Type:    TypeLowerCaseString,
+					Default: "bar",
+				},
+			},
+			map[string]interface{}{},
+			"foo",
+			"bar",
+		},
+
 		"int type, int value": {
 			map[string]*FieldSchema{
 				"foo": &FieldSchema{Type: TypeInt},

logical/framework/field_type.go

@@ -26,6 +26,10 @@ const (
 	// a string field
 	TypeCommaStringSlice
 
+	// TypeLowerCaseString is a helper for TypeString that returns a lowercase
+	// version of the provided string
+	TypeLowerCaseString
+
 	// TypeNameString represents a name that is URI safe and follows specific
 	// rules.  These rules include start and end with an alphanumeric
 	// character and characters in the middle can be alphanumeric or . or -.
@@ -44,6 +48,8 @@ func (t FieldType) String() string {
 	switch t {
 	case TypeString:
 		return "string"
+	case TypeLowerCaseString:
+		return "lowercase string"
 	case TypeNameString:
 		return "name string"
 	case TypeInt: