[FAB-18479] Log error if orderer can't forward SubmitRequest to Raft …

…leader

If order cannot forward client transaction SubmitRequest to Raft leader,
it only logged it in a debug message. And since the error does
not get returned to the client either, it is difficult to identify
and troubleshoot.

This commit changes the message to an error in the orderer log.

Signed-off-by: David Enyeart <[email protected]>
(cherry picked from commit e8e39e6)

orderer/common/cluster/comm.go

@@ -521,26 +521,26 @@ func (stream *Stream) sendOrDrop(request *orderer.StepRequest, allowDrop bool) e
 	case <-stream.abortChan:
 		return errors.Errorf("stream %d aborted", stream.ID)
 	case stream.sendBuff <- request:
+		// Note - async send, errors are not returned back
 		return nil
 	case <-stream.commShutdown:
 		return nil
 	}
 }
 
 // sendMessage sends the request down the stream
+// Note - any errors are swallowed and not returned back - TODO Is this intentional? Shouldn't SubmitRequest errors get returned to client?
 func (stream *Stream) sendMessage(request *orderer.StepRequest) {
 	start := time.Now()
 	var err error
 	defer func() {
-		if !stream.Logger.IsEnabledFor(zap.DebugLevel) {
-			return
-		}
-		var result string
+		message := fmt.Sprintf("Send of %s to %s(%s) took %v",
+			requestAsString(request), stream.NodeName, stream.Endpoint, time.Since(start))
 		if err != nil {
-			result = fmt.Sprintf("but failed due to %s", err.Error())
+			stream.Logger.Errorf("%s but failed due to %s", message, err.Error())
+		} else {
+			stream.Logger.Debug(message)
 		}
-		stream.Logger.Debugf("Send of %s to %s(%s) took %v %s", requestAsString(request),
-			stream.NodeName, stream.Endpoint, time.Since(start), result)
 	}()
 
 	f := func() (*orderer.StepResponse, error) {