Hold a plan whose backup failed or stayed silent, say it, and ask again by a verb (issue 1066)

cmd/mesh-controller/delivery.go

@@ -884,6 +884,19 @@ func deliveryCommand(ctx context.Context, args []string) error {
 		fmt.Printf("%s stopped by %s at tier %d of %d; what was asked still builds and registers, nothing further "+
 			"is asked or sent\n", p.ID, *by, p.Tier, len(p.Tiers))
 		return nil
+	case "backups-again":
+		if len(positionals) != 1 || strings.TrimSpace(*why) == "" {
+			return errors.New("delivery backups-again <plan> --why <text> [--by <who>]")
+		}
+		var p inventory.Plan
+		var again []inventory.PlanBackup
+		if err := sayingOnTheBus(ctx, inv, func() (err error) {
+			p, again, err = backupsAgain(ctx, inv, positionals[0], *by, strings.TrimSpace(*why))
+			return err
+		}); err != nil {
+			return err
+		}
+		return answer(map[string]any{"plan": p.ID, "asked_again": again})
 	case "walks":
 		var walks []inventory.Plan
 		if *planID != "" {
@@ -924,7 +937,7 @@ func deliveryCommand(ctx context.Context, args []string) error {
 		return answer(map[string]any{"held": deliverySeatHeld(entries), "walks": walks,
 			"own-path": sortedKeysOf(ownPathWords())})
 	}
-	return fmt.Errorf("delivery %s: plan, order, check, go, stop or walks", sub)
+	return fmt.Errorf("delivery %s: plan, order, check, go, stop, backups-again or walks", sub)
 }
 
 // appliedFrom answers a machine's own report of the send a walk made to it from the controller's `apply` durations