Merge: * /control/version.json: retry up to 3 times after DNS resolve…

… of static.adguard.com has failed

Close AdguardTeam#934

* commit 'd4c012220edc52e7d47808f1d83ce9ca664f73d3':
  * control: add link to the issue on github
  * /control/version.json: retry up to 3 times after DNS resolve of static.adguard.com has failed

home/control_update.go

@@ -85,8 +85,17 @@ func handleGetVersionJSON(w http.ResponseWriter, r *http.Request) {
  }
  }
 
- log.Tracef("Downloading data from %s", versionCheckURL)
- resp, err := config.client.Get(versionCheckURL)
+ var resp *http.Response
+ for i := 0; i != 3; i++ {
+ log.Tracef("Downloading data from %s", versionCheckURL)
+ resp, err = config.client.Get(versionCheckURL)
+ 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
+ continue
+ }
+ break
+ }
  if err != nil {
  httpError(w, http.StatusBadGateway, "Couldn't get version check json from %s: %T %s\n", versionCheckURL, err, err)
  return