Coordinator Role: json marshaling as string

coordinator/role/role.go

@@ -1,5 +1,10 @@
 package role
 
+import (
+	"encoding/json"
+	"strings"
+)
+
 //go:generate stringer -type=Role
 
 // Role is a peer's role.
@@ -10,3 +15,26 @@ const (
 	Coordinator
 	Node
 )
+
+// MarshalJSON marshals the Role to JSON string.
+func (r Role) MarshalJSON() ([]byte, error) {
+	return json.Marshal(r.String())
+}
+
+// UnmarshalJSON unmarshals the Role from JSON string.
+func (r *Role) UnmarshalJSON(b []byte) error {
+	var roleString string
+	if err := json.Unmarshal(b, &roleString); err != nil {
+		return err
+	}
+	switch strings.ToLower(roleString) {
+	case "coordinator":
+		*r = Coordinator
+
+	case "node":
+		*r = Node
+	default:
+		*r = Unknown
+	}
+	return nil
+}