retry failed messages

extras/util/slack.go

@@ -79,7 +79,13 @@ func sendToSlack(channel, username, message string) error {
 		err = errors.Err("no slack token provided")
 	} else {
 		log.Debugln("slack: " + channel + ": " + message)
+		for {
 			_, _, err = slackApi.PostMessage(channel, slack.MsgOptionText(message, false), slack.MsgOptionUsername(username))
+			if strings.Contains(err.Error(), "timeout awaiting response headers") {
+				continue
+			}
+			break
+		}
 	}
 
 	if err != nil {