Try harder to get holidays

internal/holy/cronTask.go

@@ -2,19 +2,55 @@ package holy
 
 import (
 	"tg-holy-bot/internal/log"
+	"time"
 )
 
 // CronTask sends generated holiday list to the channel.
 func CronTask() {
+	var (
+		err     error
+		errcnt  int
+		phrase  string
+		timeout time.Duration
+	)
+
 	log.Info("Cron Task triggered")
 
-	phrase, err := APIClient()
+	for {
+		phrase, err = APIClient()
 
 		if err != nil {
-		log.Errorf("Unable to get holidays: %s", err)
+			errcnt++
+
+			log.Errorf("Unable to get holidays (try %d/15): %s", errcnt, err)
+
+			switch errcnt {
+			case 0, 1, 2:
+				timeout = 1 * time.Second
+
+			case 3, 4, 5:
+				timeout = 5 * time.Second
+
+			case 6, 7, 8:
+				timeout = 1 * time.Minute
+
+			case 9, 10, 11:
+				timeout = 5 * time.Minute
+
+			case 12, 13, 14:
+				timeout = 1 * time.Hour
+
+			default:
+				log.Error("Giveup trying to get holidays")
 
 				return
 			}
+		} else {
+			break
+		}
+
+		time.Sleep(timeout)
+	}
 
 	if _, err = Bot.SendMessage(phrase, Config.ChannelID, nil); err != nil {
 		log.Errorf("Unable to send message to channel: %s", err)