Check for JSON-RPC errors, and add better logging for it

src/rest_server.cpp

@@ -43,12 +43,14 @@
 #include "lmdb/util.h"                 // monero/src
 #include "net/http_base.h"             // monero/contrib/epee/include
 #include "net/net_parse_helpers.h"     // monero/contrib/epee/include
+#include "rpc/client.h"
 #include "rpc/daemon_messages.h"       // monero/src
 #include "rpc/light_wallet.h"
 #include "rpc/rates.h"
 #include "util/http_server.h"
 #include "util/gamma_picker.h"
 #include "util/random_outputs.h"
+#include "util/source_location.h"
 #include "wire/json.h"
 
 namespace lws
@@ -367,7 +369,7 @@ namespace lws
           epee::byte_slice msg = rpc::client::make_message("get_output_histogram", histogram_req);
           MONERO_CHECK(client->send(std::move(msg), std::chrono::seconds{10}));
 
-          auto histogram_resp = client->receive<histogram_rpc::Response>(std::chrono::minutes{3});
+          auto histogram_resp = client->receive<histogram_rpc::Response>(std::chrono::minutes{3}, MLWS_CURRENT_LOCATION);
           if (!histogram_resp)
             return histogram_resp.error();
           if (histogram_resp->histogram.size() != histogram_req.amounts.size())
@@ -396,7 +398,7 @@ namespace lws
           MONERO_CHECK(client->send(std::move(msg), std::chrono::seconds{10}));
 
           auto distribution_resp =
-            client->receive<distribution_rpc::Response>(std::chrono::minutes{3});
+            client->receive<distribution_rpc::Response>(std::chrono::minutes{3}, MLWS_CURRENT_LOCATION);
           if (!distribution_resp)
             return distribution_resp.error();
 
@@ -445,7 +447,7 @@ namespace lws
             epee::byte_slice msg = rpc::client::make_message("get_output_keys", keys_req);
             MONERO_CHECK(client->send(std::move(msg), std::chrono::seconds{10}));
 
-            auto keys_resp = client->receive<get_keys_rpc::Response>(std::chrono::seconds{10});
+            auto keys_resp = client->receive<get_keys_rpc::Response>(std::chrono::seconds{10}, MLWS_CURRENT_LOCATION);
             if (!keys_resp)
               return keys_resp.error();
 
@@ -526,7 +528,7 @@ namespace lws
         if (received < std::uint64_t(req.amount))
           return {lws::error::account_not_found};
 
-        const auto resp = client->receive<rpc_command::Response>(std::chrono::seconds{20});
+        const auto resp = client->receive<rpc_command::Response>(std::chrono::seconds{20}, MLWS_CURRENT_LOCATION);
         if (!resp)
           return resp.error();
 
@@ -638,7 +640,7 @@ namespace lws
         epee::byte_slice message = rpc::client::make_message("send_raw_tx_hex", daemon_req);
         MONERO_CHECK(client->send(std::move(message), std::chrono::seconds{10}));
 
-        const auto daemon_resp = client->receive<transaction_rpc::Response>(std::chrono::seconds{20});
+        const auto daemon_resp = client->receive<transaction_rpc::Response>(std::chrono::seconds{20}, MLWS_CURRENT_LOCATION);
         if (!daemon_resp)
           return daemon_resp.error();
         if (!daemon_resp->relayed)

src/rpc/client.cpp

@@ -37,6 +37,7 @@
 #include "misc_log_ex.h"     // monero/contrib/epee/include
 #include "net/http_client.h" // monero/contrib/epee/include
 #include "net/zmq.h"         // monero/src
+#include "serialization/json_object.h" // monero/src
 
 namespace lws
 {
@@ -160,6 +161,32 @@ namespace rpc
     };
   } // detail
 
+  expect<void> client::get_response(cryptonote::rpc::Message& response, const std::chrono::seconds timeout, const source_location loc)
+  {
+    expect<std::string> message = get_message(timeout);
+    if (!message)
+      return message.error();
+
+    try
+    {
+      cryptonote::rpc::FullMessage fm{std::move(*message)};
+      const cryptonote::rpc::error json_error = fm.getError();
+      if (!json_error.use)
+      {
+        response.fromJson(fm.getMessage());
+        return success();
+      }
+
+      MERROR("Server returned RPC error: " << json_error.message << " with code " << json_error.code << " called from " << loc);
+    }
+    catch (const cryptonote::json::JSON_ERROR& error)
+    {
+      MERROR("Failed to parse json response: " << error.what() << " called from " << loc);
+    }
+
+    return {lws::error::bad_daemon_response};
+  }
+
   expect<std::string> client::get_message(std::chrono::seconds timeout)
   {
     MONERO_PRECOND(ctx != nullptr);

src/rpc/client.h

@@ -38,6 +38,7 @@
 #include "rpc/message.h"   // monero/src
 #include "rpc/daemon_pub.h"
 #include "rpc/rates.h"
+#include "util/source_location.h"
 
 namespace lws
 {
@@ -70,6 +71,9 @@ namespace rpc
       : ctx(std::move(ctx)), daemon(), daemon_sub(), signal_sub()
     {}
 
+    //! Expect `response` as the next message payload unless error.
+    expect<void> get_response(cryptonote::rpc::Message& response, std::chrono::seconds timeout, source_location loc);
+
   public:
     //! A client with no connection (all send/receive functions fail).
     explicit client() noexcept
@@ -125,18 +129,13 @@ namespace rpc
     //! \return Next available RPC message response from server
     expect<std::string> get_message(std::chrono::seconds timeout);
 
-    //! \return RPC response `M`, waiting a max of `timeout` seconds.
+    //! \return RPC response `M`, waiting a max of `timeout` seconds. Log errors as from `loc`.
     template<typename M>
-    expect<M> receive(std::chrono::seconds timeout)
+    expect<M> receive(const std::chrono::seconds timeout, const source_location loc = {})
     {
-      expect<std::string> message = get_message(timeout);
-      if (!message)
-        return message.error();
-
-      cryptonote::rpc::FullMessage fm{std::move(*message)};
-      M out{};
-      out.fromJson(fm.getMessage());
-      return out;
+      M response{};
+      MONERO_CHECK(get_response(response, timeout, loc));
+      return response;
     }
 
     /*!

src/scanner.cpp

@@ -50,6 +50,7 @@
 #include "rpc/daemon_messages.h"     // monero/src
 #include "rpc/daemon_zmq.h"
 #include "rpc/json.h"
+#include "util/source_location.h"
 #include "util/transactions.h"
 #include "wire/json.h"
 
@@ -705,7 +706,7 @@ namespace lws
       expect<get_hashes::Response> resp{lws::error::daemon_timeout};
       start = std::chrono::steady_clock::now();
 
-      while (!(resp = client.receive<get_hashes::Response>(std::chrono::seconds{1})))
+      while (!(resp = client.receive<get_hashes::Response>(std::chrono::seconds{1}, MLWS_CURRENT_LOCATION)))
       {
         if (!scanner::is_running())
           return {lws::error::signal_abort_process};

src/util/CMakeLists.txt

@@ -26,8 +26,8 @@
 # STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 # THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-set(monero-lws-util_sources gamma_picker.cpp random_outputs.cpp transactions.cpp)
-set(monero-lws-util_headers fwd.h gamma_picker.h http_server.h random_outputs.h transactions.h)
+set(monero-lws-util_sources gamma_picker.cpp random_outputs.cpp source_location.cpp transactions.cpp)
+set(monero-lws-util_headers fwd.h gamma_picker.h http_server.h random_outputs.h source_location.h transactions.h)
 
 add_library(monero-lws-util ${monero-lws-util_sources} ${monero-lws-util_headers})
 target_link_libraries(monero-lws-util monero::libraries)