Log DNS optimistic background refresh outcomes

dns/client.go

@@ -498,7 +498,7 @@ func (c *Client) backgroundRefreshDNS(transport adapter.DNSTransport, question d
 		response, err := c.exchangeToTransport(ctx, transport, message)
 		if err != nil {
 			if c.logger != nil {
-				c.logger.Debug("optimistic refresh failed for ", FqdnToDomain(question.Name), ": ", err)
+				c.logger.DebugContext(ctx, "optimistic refresh failed for ", FqdnToDomain(question.Name), ": ", err)
 			}
 			return
 		}
@@ -510,6 +510,9 @@ func (c *Client) backgroundRefreshDNS(transport adapter.DNSTransport, question d
 				rejected = !responseChecker(response)
 			}
 			if rejected {
+				if c.logger != nil {
+					c.logger.DebugContext(ctx, "optimistic refresh rejected for ", FqdnToDomain(question.Name))
+				}
 				if c.rdrc != nil {
 					c.rdrc.SaveRDRCAsync(transport.Tag(), question.Name, question.Qtype, c.logger)
 				}
@@ -520,6 +523,7 @@ func (c *Client) backgroundRefreshDNS(transport adapter.DNSTransport, question d
 		}
 		timeToLive := applyResponseOptions(question, response, options)
 		c.storeCache(transport, question, response, timeToLive)
+		logRefreshedResponse(c.logger, ctx, response, timeToLive)
 	}()
 }
 

dns/client_log.go

@@ -48,6 +48,19 @@ func logExchangedResponse(logger logger.ContextLogger, ctx context.Context, resp
 	}
 }
 
+func logRefreshedResponse(logger logger.ContextLogger, ctx context.Context, response *dns.Msg, ttl uint32) {
+	if logger == nil || len(response.Question) == 0 {
+		return
+	}
+	domain := FqdnToDomain(response.Question[0].Name)
+	logger.DebugContext(ctx, "refreshed ", domain, " ", dns.RcodeToString[response.Rcode], " ", ttl)
+	for _, recordList := range [][]dns.RR{response.Answer, response.Ns, response.Extra} {
+		for _, record := range recordList {
+			logger.InfoContext(ctx, "refreshed ", dns.Type(record.Header().Rrtype).String(), " ", FormatQuestion(record.String()))
+		}
+	}
+}
+
 func logRejectedResponse(logger logger.ContextLogger, ctx context.Context, response *dns.Msg) {
 	if logger == nil || len(response.Question) == 0 {
 		return