s3_client: Check if response contains error

S3 can reply with error even if it's replying using status 200. Most of
our parsing is done independent of status code (we're trying to check
error fields every time). But in case of delete objects reply we're not
trying to parse error fields if the status is 200. This commit fixes
this and before any attempt at parsing the response is done we're
checking if the 'Error.Code' field is present.

(cherry picked from commit df299db)

src/v/cloud_storage_clients/s3_client.cc

@@ -34,13 +34,15 @@
 
 #include <boost/beast/core/error.hpp>
 #include <boost/beast/http/field.hpp>
+#include <boost/beast/http/status.hpp>
 #include <boost/property_tree/ptree.hpp>
 #include <boost/property_tree/xml_parser.hpp>
 #include <gnutls/crypto.h>
 
 #include <bit>
 #include <exception>
 #include <utility>
+#include <variant>
 
 namespace cloud_storage_clients {
 
@@ -812,10 +814,22 @@ ss::future<> s3_client::do_delete_object(
       });
 }
 
-static auto iobuf_to_delete_objects_result(iobuf&& buf) {
+static std::variant<client::delete_objects_result, rest_error_response>
+iobuf_to_delete_objects_result(iobuf&& buf) {
     auto root = util::iobuf_to_ptree(std::move(buf), s3_log);
     auto result = client::delete_objects_result{};
     try {
+        if (root.count("Error.Code") > 0) {
+            // This is an error response. S3 can reply with 200 error code and
+            // error response in the body.
+            constexpr const char* empty = "";
+            auto code = root.get<ss::sstring>("Error.Code", empty);
+            auto msg = root.get<ss::sstring>("Error.Message", empty);
+            auto rid = root.get<ss::sstring>("Error.RequestId", empty);
+            auto res = root.get<ss::sstring>("Error.Resource", empty);
+            rest_error_response err(code, msg, rid, res);
+            return err;
+        }
         for (auto const& [tag, value] : root.get_child("DeleteResult")) {
             if (tag != "Error") {
                 continue;
@@ -880,8 +894,15 @@ auto s3_client::do_delete_objects(
                     return parse_rest_error_response<delete_objects_result>(
                       status, std::move(res));
                 }
-                return ss::make_ready_future<delete_objects_result>(
-                  iobuf_to_delete_objects_result(std::move(res)));
+                auto parse_result = iobuf_to_delete_objects_result(
+                  std::move(res));
+                if (std::holds_alternative<client::delete_objects_result>(
+                      parse_result)) {
+                    return ss::make_ready_future<delete_objects_result>(
+                      std::get<client::delete_objects_result>(parse_result));
+                }
+                return ss::make_exception_future<delete_objects_result>(
+                  std::get<rest_error_response>(parse_result));
             });
       });
 }