From 03f590d98e67b7b1d57bb0f9a4cca7e735384128 Mon Sep 17 00:00:00 2001
From: Omri Bahumi <omrib@fb.com>
Date: Sun, 22 Aug 2021 17:04:35 +0300
Subject: [PATCH] httpError: write error string as body in 502 response

---
 https.go | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/https.go b/https.go
index 6fcf17a9..e98c6cef 100644
--- a/https.go
+++ b/https.go
@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"crypto/tls"
 	"errors"
+	"fmt"
 	"io"
 	"io/ioutil"
 	"net"
@@ -108,6 +109,7 @@ func (proxy *ProxyHttpServer) handleHttps(w http.ResponseWriter, r *http.Request
 		}
 		targetSiteCon, err := proxy.connectDial("tcp", host)
 		if err != nil {
+			ctx.Warnf("Error dialing to %s: %s", host, err.Error())
 			httpError(proxyClient, ctx, err)
 			return
 		}
@@ -293,7 +295,8 @@ func (proxy *ProxyHttpServer) handleHttps(w http.ResponseWriter, r *http.Request
 }
 
 func httpError(w io.WriteCloser, ctx *ProxyCtx, err error) {
-	if _, err := io.WriteString(w, "HTTP/1.1 502 Bad Gateway\r\n\r\n"); err != nil {
+	errStr := fmt.Sprintf("HTTP/1.1 502 Bad Gateway\r\nContent-Type: text/plain\r\nContent-Length: %d\r\n\r\n%s", len(err.Error()), err.Error())
+	if _, err := io.WriteString(w, errStr); err != nil {
 		ctx.Warnf("Error responding to client: %s", err)
 	}
 	if err := w.Close(); err != nil {