graphql-engine/server/src-lib/Hasura/Eventing/Common.hs

module Hasura.Eventing.Common
  ( LockedEventsCtx (..),
    saveLockedEvents,
    removeEventFromLockedEvents,
  )
where

import Control.Concurrent.STM.TVar
import Control.Monad.STM
import Data.Set qualified as Set
import Hasura.Prelude
import Hasura.RQL.Types.Action (LockedActionEventId)
import Hasura.RQL.Types.Common
import Hasura.RQL.Types.Eventing (EventId)
import Hasura.RQL.Types.ScheduledTrigger (CronEventId, OneOffScheduledEventId)

data LockedEventsCtx = LockedEventsCtx
  { leCronEvents :: TVar (Set.Set CronEventId),
    leOneOffEvents :: TVar (Set.Set OneOffScheduledEventId),
    leEvents :: TVar (HashMap SourceName (Set.Set EventId)),
    leActionEvents :: TVar (Set.Set LockedActionEventId)
  }

-- | After the events are fetched from the DB, we store the locked events
--   in a hash set(order doesn't matter and look ups are faster) in the
--   event engine context
saveLockedEvents :: (MonadIO m) => [EventId] -> TVar (Set.Set EventId) -> m ()
saveLockedEvents eventIds lockedEvents =
  liftIO $
    atomically $ do
      lockedEventsVals <- readTVar lockedEvents
      writeTVar lockedEvents
        $! Set.union lockedEventsVals
        $ Set.fromList eventIds

-- | Remove an event from the 'LockedEventsCtx' after it has been processed
removeEventFromLockedEvents ::
  MonadIO m => EventId -> TVar (Set.Set EventId) -> m ()
removeEventFromLockedEvents eventId lockedEvents =
  liftIO $
    atomically $ do
      lockedEventsVals <- readTVar lockedEvents
      writeTVar lockedEvents $! Set.delete eventId lockedEventsVals