Add YAML parsing for LabelName

model/labelname.go

@@ -14,6 +14,8 @@
 package model
 
 import (
+	"fmt"
+	"regexp"
 	"strings"
 )
 
@@ -63,6 +65,19 @@ const (
 // therewith.
 type LabelName string
 
+// UnmarshalYAML implements the yaml.Unmarshaler interface.
+func (ln *LabelName) UnmarshalYAML(unmarshal func(interface{}) error) error {
+	var s string
+	if err := unmarshal(&s); err != nil {
+		return err
+	}
+	if !labelNameRE.MatchString(s) {
+		return fmt.Errorf("%q is not a valid label name", s)
+	}
+	*ln = LabelName(s)
+	return nil
+}
+
 // LabelNames is a sortable LabelName slice. In implements sort.Interface.
 type LabelNames []LabelName