exchange

commit a14ef50b776e583c5730ea7b0a514c04322c3ee0
parent 7d866a446d61d40781a6d5c00300032e71519f99
Author: Christian Grothoff <grothoff@gnunet.org>
Date:   Wed, 28 May 2025 14:05:34 +0200

fix refund error handling: distinguish when coin is not found from database errors

Diffstat:
M
src/exchange/taler-exchange-httpd_refund.c
 | 
50
++++++++++++++++++++++++++++++++++++--------------

1 file changed, 36 insertions(+), 14 deletions(-)
diff --git a/src/exchange/taler-exchange-httpd_refund.c b/src/exchange/taler-exchange-httpd_refund.c
@@ -36,6 +36,12 @@
 
 
 /**
+ * How often do we retry after soft database errors?
+ */
+#define MAX_RETRIES 3
+
+
+/**
  * Generate successful refund confirmation message.
  *
  * @param connection connection to the client
@@ -222,6 +228,7 @@ verify_and_execute_refund (struct MHD_Connection *connection,
   }
 
   /* Fetch the coin's denomination (hash) */
+  for (unsigned int i = 0; i < MAX_RETRIES; i++)
   {
     enum GNUNET_DB_QueryStatus qs;
 
@@ -229,21 +236,36 @@ verify_and_execute_refund (struct MHD_Connection *connection,
                                             &refund->coin.coin_pub,
                                             &rctx.known_coin_id,
                                             &refund->coin.denom_pub_hash);
-    if (0 > qs)
+    switch (qs)
     {
-      MHD_RESULT res;
-      char *dhs;
-
-      GNUNET_break (GNUNET_DB_STATUS_HARD_ERROR == qs);
-      dhs = GNUNET_STRINGS_data_to_string_alloc (
-        &refund->coin.denom_pub_hash,
-        sizeof (refund->coin.denom_pub_hash));
-      res = TALER_MHD_reply_with_error (connection,
-                                        MHD_HTTP_NOT_FOUND,
-                                        TALER_EC_EXCHANGE_REFUND_COIN_NOT_FOUND,
-                                        dhs);
-      GNUNET_free (dhs);
-      return res;
+    case GNUNET_DB_STATUS_SOFT_ERROR:
+      if (i < MAX_RETRIES - 1)
+        continue;
+    /* otherwise: fall-through */
+    case GNUNET_DB_STATUS_HARD_ERROR:
+      GNUNET_break (0);
+      return TALER_MHD_reply_with_error (connection,
+                                         MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                         TALER_EC_GENERIC_DB_FETCH_FAILED,
+                                         "get_coin_denomination");
+    case GNUNET_DB_STATUS_SUCCESS_NO_RESULTS:
+      {
+        MHD_RESULT res;
+        char *dhs;
+
+        GNUNET_break (GNUNET_DB_STATUS_HARD_ERROR == qs);
+        dhs = GNUNET_STRINGS_data_to_string_alloc (
+          &refund->coin.denom_pub_hash,
+          sizeof (refund->coin.denom_pub_hash));
+        res = TALER_MHD_reply_with_error (connection,
+                                          MHD_HTTP_NOT_FOUND,
+                                          TALER_EC_EXCHANGE_REFUND_COIN_NOT_FOUND,
+                                          dhs);
+        GNUNET_free (dhs);
+        return res;
+      }
+    case GNUNET_DB_STATUS_SUCCESS_ONE_RESULT:
+      break;
     }
   }