client: add error type field for --json outputs

src/core/protocol/commands/lock_users.rs

@@ -45,6 +45,7 @@ pub fn print_lock_users_output_status_json(output: &LockUsersResponse) {
                 name.to_string(),
                 json!({
                   "status": "error",
+                  "type": err.error_type(),
                   "error": err.to_error_message(name),
                 }),
             ),
@@ -77,4 +78,14 @@ impl LockUserError {
             }
         }
     }
+
+    pub fn error_type(&self) -> &'static str {
+        match self {
+            LockUserError::SanitizationError(_) => "sanitization-error",
+            LockUserError::OwnershipError(_) => "ownership-error",
+            LockUserError::UserDoesNotExist => "user-does-not-exist",
+            LockUserError::UserIsAlreadyLocked => "user-is-already-locked",
+            LockUserError::MySqlError(_) => "mysql-error",
+        }
+    }
 }