One canon I'd recalled for festival (6)
I believe the answer is:
diwali
'festival' is the definition.
(Hindu festival)
'one canon i'd recalled' is the wordplay.
'one' becomes 'i' (Roman numeral).
'canon' becomes 'law' (canon can mean a law or principle).
'recalled' says the letters should be written backwards.
'i'+'law'+'id'='ilawid'
'ilawid' backwards is 'DIWALI'.
'for' acts as a link.
(Other definitions for diwali that I've seen before include "Hindu festival of lights" , "Light festival" , "Festival in honour of Lakshmi" , "Hindu festival; I'd wail (anag.)" , "Indian festival" .)