From fa8aa02270a163244aaa583778389e98cd2ff9a2 Mon Sep 17 00:00:00 2001
From: Nuno Diegues <nuno@cloudflare.com>
Date: Wed, 28 Jul 2021 23:31:22 +0100
Subject: [PATCH] TUN-4819: Tolerate protocol TXT record lookup failing

---
 connection/protocol.go      | 5 ++++-
 connection/protocol_test.go | 3 ++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/connection/protocol.go b/connection/protocol.go
index 2f6dea92..c4f5ed67 100644
--- a/connection/protocol.go
+++ b/connection/protocol.go
@@ -172,7 +172,10 @@ func NewProtocolSelector(
 
 	http2Percentage, err := fetchFunc()
 	if err != nil {
-		return nil, err
+		log.Err(err).Msg("Unable to lookup protocol. Defaulting to `http2`. If this fails, you can set `--protocol h2mux` in your cloudflared command.")
+		return &staticProtocolSelector{
+			current: HTTP2,
+		}, nil
 	}
 	if protocolFlag == HTTP2.String() {
 		if http2Percentage < 0 {
diff --git a/connection/protocol_test.go b/connection/protocol_test.go
index a119ec42..b4a6299a 100644
--- a/connection/protocol_test.go
+++ b/connection/protocol_test.go
@@ -158,7 +158,8 @@ func TestNewProtocolSelector(t *testing.T) {
 			protocol:          "unknown",
 			fetchFunc:         mockFetcherWithError(),
 			namedTunnelConfig: testNamedTunnelConfig,
-			wantErr:           true,
+			expectedProtocol:  HTTP2,
+			wantErr:           false,
 		},
 	}