From 4a223f52038cb77bbf97ca3f3345550dea4e12d8 Mon Sep 17 00:00:00 2001
From: Francis Lavoie <lavofr@gmail.com>
Date: Mon, 2 May 2022 13:44:28 -0400
Subject: [PATCH] reverseproxy: Fix Caddyfile support for `replace_status`
 (#4754)

---
 .../reverse_proxy_handle_response.txt         | 23 +++++++++++--
 modules/caddyhttp/reverseproxy/caddyfile.go   | 33 +++++++++----------
 2 files changed, 37 insertions(+), 19 deletions(-)

diff --git a/caddytest/integration/caddyfile_adapt/reverse_proxy_handle_response.txt b/caddytest/integration/caddyfile_adapt/reverse_proxy_handle_response.txt
index 1b6162dc..f6a26090 100644
--- a/caddytest/integration/caddyfile_adapt/reverse_proxy_handle_response.txt
+++ b/caddytest/integration/caddyfile_adapt/reverse_proxy_handle_response.txt
@@ -1,8 +1,13 @@
 :8884
 
 reverse_proxy 127.0.0.1:65535 {
-	@changeStatus status 500
-	replace_status @changeStatus 400
+	@500 status 500
+	replace_status @500 400
+
+	@all status 2xx 3xx 4xx 5xx
+	replace_status @all {http.error.status_code}
+
+	replace_status {http.error.status_code}
 
 	@accel header X-Accel-Redirect *
 	handle_response @accel {
@@ -78,6 +83,17 @@ reverse_proxy 127.0.0.1:65535 {
 											},
 											"status_code": 400
 										},
+										{
+											"match": {
+												"status_code": [
+													2,
+													3,
+													4,
+													5
+												]
+											},
+											"status_code": "{http.error.status_code}"
+										},
 										{
 											"match": {
 												"headers": {
@@ -228,6 +244,9 @@ reverse_proxy 127.0.0.1:65535 {
 												}
 											]
 										},
+										{
+											"status_code": "{http.error.status_code}"
+										},
 										{
 											"routes": [
 												{
diff --git a/modules/caddyhttp/reverseproxy/caddyfile.go b/modules/caddyhttp/reverseproxy/caddyfile.go
index b3f90106..14de2300 100644
--- a/modules/caddyhttp/reverseproxy/caddyfile.go
+++ b/modules/caddyhttp/reverseproxy/caddyfile.go
@@ -627,22 +627,24 @@ func (h *Handler) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 
 			case "replace_status":
 				args := d.RemainingArgs()
-				if len(args) != 2 {
-					return d.Errf("must have two arguments: a response matcher and a status code")
+				if len(args) != 1 && len(args) != 2 {
+					return d.Errf("must have one or two arguments: an optional response matcher, and a status code")
 				}
 
-				if !strings.HasPrefix(args[0], matcherPrefix) {
-					return d.Errf("must use a named response matcher, starting with '@'")
-				}
+				responseHandler := caddyhttp.ResponseHandler{}
 
-				foundMatcher, ok := h.responseMatchers[args[0]]
-				if !ok {
-					return d.Errf("no named response matcher defined with name '%s'", args[0][1:])
-				}
-
-				_, err := strconv.Atoi(args[1])
-				if err != nil {
-					return d.Errf("bad integer value '%s': %v", args[1], err)
+				if len(args) == 2 {
+					if !strings.HasPrefix(args[0], matcherPrefix) {
+						return d.Errf("must use a named response matcher, starting with '@'")
+					}
+					foundMatcher, ok := h.responseMatchers[args[0]]
+					if !ok {
+						return d.Errf("no named response matcher defined with name '%s'", args[0][1:])
+					}
+					responseHandler.Match = &foundMatcher
+					responseHandler.StatusCode = caddyhttp.WeakString(args[1])
+				} else if len(args) == 1 {
+					responseHandler.StatusCode = caddyhttp.WeakString(args[0])
 				}
 
 				// make sure there's no block, cause it doesn't make sense
@@ -652,10 +654,7 @@ func (h *Handler) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 
 				h.HandleResponse = append(
 					h.HandleResponse,
-					caddyhttp.ResponseHandler{
-						Match:      &foundMatcher,
-						StatusCode: caddyhttp.WeakString(args[1]),
-					},
+					responseHandler,
 				)
 
 			default: