The corporate authorities of any such county, city or town shall provide annually by ordinance or resolution for the levy and extension on the tax rolls of such county, city or town, and for the collection thereof, of a direct annual tax in addition to all other county, city or town taxes to be levied according to law, which shall be sufficient to meet the interest on all of said bonds promptly as the same matures, and also sufficient to fully pay each series of bonds as the same matures: PROVIDED, That such ordinance or resolution shall not be repealed until the levy therein provided for shall be fully paid, or the bonds both principal and interest shall be paid or canceled.