From 39268c754a1d87b13bc1b8e98d2446e7db85632a Mon Sep 17 00:00:00 2001
From: jvoisin <julien.voisin@dustri.org>
Date: Tue, 22 Dec 2020 11:59:09 +0100
Subject: [PATCH 1/3] Use a simple backoff for retrying the update

- Not sleeping might be too fast for the DNS server to restart
- Fix the link to the issue
---
 internal/home/controlupdate.go | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/internal/home/controlupdate.go b/internal/home/controlupdate.go
index dcf428b9..9e69617c 100644
--- a/internal/home/controlupdate.go
+++ b/internal/home/controlupdate.go
@@ -9,6 +9,7 @@ import (
 	"runtime"
 	"strings"
 	"syscall"
+	"time"
 
 	"github.com/AdguardTeam/AdGuardHome/internal/sysutil"
 	"github.com/AdguardTeam/AdGuardHome/internal/update"
@@ -46,7 +47,8 @@ func handleGetVersionJSON(w http.ResponseWriter, r *http.Request) {
 		Context.controlLock.Unlock()
 		if err != nil && strings.HasSuffix(err.Error(), "i/o timeout") {
 			// This case may happen while we're restarting DNS server
-			// https://github.com/AdguardTeam/AdGuardHome/internal/issues/934
+			// https://github.com/AdguardTeam/AdGuardHome/issues/934
+			time.Sleep(time.Duration(i) * time.Second)
 			continue
 		}
 		break

From 664ef85c6cd39762887c4b88f154af29c7ba44c6 Mon Sep 17 00:00:00 2001
From: Ainar Garipov <A.Garipov@AdGuard.COM>
Date: Thu, 24 Dec 2020 21:44:36 +0300
Subject: [PATCH 2/3] home: improve error handling

---
 internal/home/controlupdate.go | 39 ++++++++++++++++++++++++++--------
 1 file changed, 30 insertions(+), 9 deletions(-)

diff --git a/internal/home/controlupdate.go b/internal/home/controlupdate.go
index 9e69617c..17b60645 100644
--- a/internal/home/controlupdate.go
+++ b/internal/home/controlupdate.go
@@ -2,12 +2,12 @@ package home
 
 import (
 	"encoding/json"
+	"errors"
 	"net/http"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"runtime"
-	"strings"
 	"syscall"
 	"time"
 
@@ -20,6 +20,13 @@ type getVersionJSONRequest struct {
 	RecheckNow bool `json:"recheck_now"`
 }
 
+// temoraryError is the interface for temporary errors from the Go standard
+// library.
+type temoraryError interface {
+	error
+	Temporary() (ok bool)
+}
+
 // Get the latest available version from the Internet
 func handleGetVersionJSON(w http.ResponseWriter, r *http.Request) {
 	if Context.disableUpdate {
@@ -42,15 +49,29 @@ func handleGetVersionJSON(w http.ResponseWriter, r *http.Request) {
 
 	var info update.VersionInfo
 	for i := 0; i != 3; i++ {
-		Context.controlLock.Lock()
-		info, err = Context.updater.GetVersionResponse(req.RecheckNow)
-		Context.controlLock.Unlock()
-		if err != nil && strings.HasSuffix(err.Error(), "i/o timeout") {
-			// This case may happen while we're restarting DNS server
-			// https://github.com/AdguardTeam/AdGuardHome/issues/934
-			time.Sleep(time.Duration(i) * time.Second)
-			continue
+		func() {
+			Context.controlLock.Lock()
+			defer Context.controlLock.Unlock()
+
+			info, err = Context.updater.GetVersionResponse(req.RecheckNow)
+		}()
+
+		if err != nil {
+			var terr temoraryError
+			if errors.As(err, &terr) && terr.Temporary() {
+				// Temporary network error.  This case may happen while
+				// we're restarting our DNS server.  Log and sleep for
+				// some time.
+				//
+				// See https://github.com/AdguardTeam/AdGuardHome/issues/934.
+				d := time.Duration(i) * time.Second
+				log.Info("temp net error: %q; sleeping for %s and retrying", err, d)
+				time.Sleep(d)
+
+				continue
+			}
 		}
+
 		break
 	}
 	if err != nil {

From 4bc1337cc9cb4f15f2fd93f638798a94339a2ed9 Mon Sep 17 00:00:00 2001
From: Ainar Garipov <A.Garipov@AdGuard.COM>
Date: Fri, 25 Dec 2020 12:54:22 +0300
Subject: [PATCH 3/3] home: imp naming

---
 internal/home/controlupdate.go | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/internal/home/controlupdate.go b/internal/home/controlupdate.go
index 17b60645..ff9dc4ab 100644
--- a/internal/home/controlupdate.go
+++ b/internal/home/controlupdate.go
@@ -20,9 +20,9 @@ type getVersionJSONRequest struct {
 	RecheckNow bool `json:"recheck_now"`
 }
 
-// temoraryError is the interface for temporary errors from the Go standard
+// temporaryError is the interface for temporary errors from the Go standard
 // library.
-type temoraryError interface {
+type temporaryError interface {
 	error
 	Temporary() (ok bool)
 }
@@ -57,7 +57,7 @@ func handleGetVersionJSON(w http.ResponseWriter, r *http.Request) {
 		}()
 
 		if err != nil {
-			var terr temoraryError
+			var terr temporaryError
 			if errors.As(err, &terr) && terr.Temporary() {
 				// Temporary network error.  This case may happen while
 				// we're restarting our DNS server.  Log and sleep for