Hasql.Queue.Internal

Internal module. Changes to this modules are not reflected in the package version.

Documentation

data State

A Payload can exist in three states in the queue, Enqueued, and Dequeued. A Payload starts in the Enqueued state and is locked so some sort of process can occur with it, usually something in IO. Once the processing is complete, the Payload is moved the Dequeued state, which is the terminal state.

Constructors

Enqueued

Failed

Instances

Bounded State

Defined in Hasql.Queue.Internal

Methods

minBound :: State

maxBound :: State

Enum State

Defined in Hasql.Queue.Internal

Methods

succ :: State -> State

pred :: State -> State

toEnum :: Int -> State

fromEnum :: State -> Int

enumFrom :: State -> [State]

enumFromThen :: State -> State -> [State]

enumFromTo :: State -> State -> [State]

enumFromThenTo :: State -> State -> State -> [State]

Eq State

Defined in Hasql.Queue.Internal

Methods

(==) :: State -> State -> Bool

(/=) :: State -> State -> Bool

Ord State

Defined in Hasql.Queue.Internal

Methods

compare :: State -> State -> Ordering

(<) :: State -> State -> Bool

(<=) :: State -> State -> Bool

(>) :: State -> State -> Bool

(>=) :: State -> State -> Bool

max :: State -> State -> State

min :: State -> State -> State

Show State

Defined in Hasql.Queue.Internal

Methods

showsPrec :: Int -> State -> ShowS

show :: State -> String

showList :: [State] -> ShowS

state :: Params a -> Result b -> ByteString -> Statement a b

stateDecoder :: Value State

stateEncoder :: Value State

initialPayloadId :: PayloadId

newtype PayloadId

Internal payload id. Used by the public api as continuation token for pagination.

Constructors

PayloadId

Fields

• unPayloadId :: Int64

Instances

Eq PayloadId

Defined in Hasql.Queue.Internal

Methods

(==) :: PayloadId -> PayloadId -> Bool

(/=) :: PayloadId -> PayloadId -> Bool

Show PayloadId

Defined in Hasql.Queue.Internal

Methods

showsPrec :: Int -> PayloadId -> ShowS

show :: PayloadId -> String

showList :: [PayloadId] -> ShowS

data Payload a

The fundemental record stored in the queue. The queue is a single table and each row consists of a Payload

Constructors

Payload

Fields

• pId :: PayloadId
• pState :: State
• pAttempts :: Int
• pModifiedAt :: Int
• pValue :: a

Instances

Eq a => Eq (Payload a)

Defined in Hasql.Queue.Internal

Methods

(==) :: Payload a -> Payload a -> Bool

(/=) :: Payload a -> Payload a -> Bool

Show a => Show (Payload a)

Defined in Hasql.Queue.Internal

Methods

showsPrec :: Int -> Payload a -> ShowS

show :: Payload a -> String

showList :: [Payload a] -> ShowS

payloadDecoder :: Value a -> Row (Payload a)

Payload decoder

payloadIdEncoder :: Value PayloadId

payloadIdDecoder :: Value PayloadId

payloadIdRow :: Row PayloadId

enqueuePayload :: Value a -> [a] -> Session [PayloadId]

dequeuePayload :: Value a -> Int -> Session [Payload a]

getPayload :: Value a -> PayloadId -> Session (Maybe (Payload a))

Get the Payload given a PayloadId

getCount :: Session Int64

Get the number of rows in the Enqueued state.

incrementAttempts :: Int -> [PayloadId] -> Session ()

newtype QueryException

Constructors

QueryException QueryError

Instances

Eq QueryException

Defined in Hasql.Queue.Internal

Methods

(==) :: QueryException -> QueryException -> Bool

(/=) :: QueryException -> QueryException -> Bool

Show QueryException

Defined in Hasql.Queue.Internal

Methods

showsPrec :: Int -> QueryException -> ShowS

show :: QueryException -> String

showList :: [QueryException] -> ShowS

Exception QueryException

Defined in Hasql.Queue.Internal

Methods

toException :: QueryException -> SomeException

fromException :: SomeException -> Maybe QueryException

displayException :: QueryException -> String

runThrow :: Session a -> Connection -> IO a

execute :: Connection -> ByteString -> IO ()

notifyPayload :: ByteString -> Connection -> IO ()

data WithNotifyHandlers

To aid in observability and white box testing

Constructors

WithNotifyHandlers

Fields

• withNotifyHandlersAfterAction :: IO ()

  An event that is trigger after the initial action, e.g. before dequeue is called.

• withNotifyHandlersBeforeNotification :: IO ()

  An event that is triggered before the blocking on a notification.

Instances

Semigroup WithNotifyHandlers

Defined in Hasql.Queue.Internal

Methods

(<>) :: WithNotifyHandlers -> WithNotifyHandlers -> WithNotifyHandlers

sconcat :: NonEmpty WithNotifyHandlers -> WithNotifyHandlers

stimes :: Integral b => b -> WithNotifyHandlers -> WithNotifyHandlers

Monoid WithNotifyHandlers

Defined in Hasql.Queue.Internal

Methods

mempty :: WithNotifyHandlers

mappend :: WithNotifyHandlers -> WithNotifyHandlers -> WithNotifyHandlers

mconcat :: [WithNotifyHandlers] -> WithNotifyHandlers

data NoRows

Constructors

NoRows

Instances

Eq NoRows

Defined in Hasql.Queue.Internal

Methods

(==) :: NoRows -> NoRows -> Bool

(/=) :: NoRows -> NoRows -> Bool

Show NoRows

Defined in Hasql.Queue.Internal

Methods

showsPrec :: Int -> NoRows -> ShowS

show :: NoRows -> String

showList :: [NoRows] -> ShowS

Exception NoRows

Defined in Hasql.Queue.Internal

Methods

toException :: NoRows -> SomeException

fromException :: SomeException -> Maybe NoRows

displayException :: NoRows -> String

withNotifyWith :: WithNotifyHandlers -> Text -> Connection -> Session a -> IO a

fst3 :: (a, b, c) -> a

snd3 :: (a, b, c) -> b

trd3 :: (a, b, c) -> c

listState :: State -> Value a -> Maybe PayloadId -> Int -> Session [(PayloadId, a)]

failures

Arguments

:: Value a

Payload decoder

-> Maybe PayloadId

Starting position of payloads. Pass Nothing to start at the beginning

-> Int

Count

-> Session [(PayloadId, a)]

Retrieve the payloads that have entered a failed state. See withDequeue for how that occurs. The function returns a list of values and an id. The id is used the starting place for the next batch of values. If Nothing is passed the list starts at the beginning.

withDequeue :: Value a -> Int -> Int -> ([a] -> IO b) -> Session (Maybe b)

delete :: [PayloadId] -> Session ()