From 3d7b4a9821af17137e01ca7969d6531c6a67ebf2 Mon Sep 17 00:00:00 2001
From: Ian Bashford <ian@bashford.net>
Date: Tue, 10 Aug 2021 22:03:29 +0100
Subject: [PATCH] debug logs DOH response headers

---
 pkg/resolvers/doh.go | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/pkg/resolvers/doh.go b/pkg/resolvers/doh.go
index c5a0016..75fbeb5 100644
--- a/pkg/resolvers/doh.go
+++ b/pkg/resolvers/doh.go
@@ -80,6 +80,14 @@ func (r *DOHResolver) Lookup(question dns.Question) (Response, error) {
 			return rsp, fmt.Errorf("error from nameserver %s", resp.Status)
 		}
 		rtt := time.Since(now)
+		// if debug, extract the response headers
+		if r.resolverOptions.Logger.IsLevelEnabled(logrus.DebugLevel) {
+			for header, value := range resp.Header {
+				r.resolverOptions.Logger.WithFields(logrus.Fields{
+					header: value,
+				}).Debug("DOH response header")
+			}
+		}
 		// extract the binary response in DNS Message.
 		body, err := ioutil.ReadAll(resp.Body)
 		if err != nil {