From b952fd8f8f568dedf8e5ae8c498eb4a2c739b35e Mon Sep 17 00:00:00 2001
From: Benny Ng <benny.tpng@gmail.com>
Date: Tue, 5 Apr 2016 18:53:45 +0800
Subject: [PATCH] revert to old Caddyfile on failed in-process restart

---
 caddy/restart.go         | 10 ++++++++++
 caddy/restart_windows.go | 11 +++++++++--
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/caddy/restart.go b/caddy/restart.go
index 99dab19e4..6237c9603 100644
--- a/caddy/restart.go
+++ b/caddy/restart.go
@@ -182,8 +182,18 @@ func restartInProc(newCaddyfile Input) error {
 		return err
 	}
 
+	caddyfileMu.Lock()
+	oldCaddyfile := caddyfile
+	caddyfileMu.Unlock()
+
 	err = Start(newCaddyfile)
 	if err != nil {
+		// revert to old Caddyfile
+		if oldErr := Start(oldCaddyfile); oldErr != nil {
+			log.Printf("[ERROR] Restart: in-process restart failed and cannot revert to old Caddyfile: %v", oldErr)
+		} else {
+			wg.Done() // take down our barrier
+		}
 		return err
 	}
 
diff --git a/caddy/restart_windows.go b/caddy/restart_windows.go
index f179ba693..b54f38a3e 100644
--- a/caddy/restart_windows.go
+++ b/caddy/restart_windows.go
@@ -7,11 +7,12 @@ import "log"
 func Restart(newCaddyfile Input) error {
 	log.Println("[INFO] Restarting")
 
+	caddyfileMu.Lock()
+	oldCaddyfile := caddyfile
 	if newCaddyfile == nil {
-		caddyfileMu.Lock()
 		newCaddyfile = caddyfile
-		caddyfileMu.Unlock()
 	}
+	caddyfileMu.Unlock()
 
 	wg.Add(1) // barrier so Wait() doesn't unblock
 
@@ -22,6 +23,12 @@ func Restart(newCaddyfile Input) error {
 
 	err = Start(newCaddyfile)
 	if err != nil {
+		// revert to old Caddyfile
+		if oldErr := Start(oldCaddyfile); oldErr != nil {
+			log.Printf("[ERROR] Restart: in-process restart failed and cannot revert to old Caddyfile: %v", oldErr)
+		} else {
+			wg.Done() // take down our barrier
+		}
 		return err
 	}