Safe Haskell	None
Language	Haskell2010

Hasql.Queue.Internal

Description

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

Synopsis

data State
- = Enqueued
- | Failed
state :: Params a -> Result b -> ByteString -> Statement a b
stateDecoder :: Value State
stateEncoder :: Value State
initialPayloadId :: PayloadId
newtype PayloadId = PayloadId {
- unPayloadId :: Int64
}
data Payload a = Payload {
- pId :: PayloadId
- pState :: State
- pAttempts :: Int
- pModifiedAt :: Int
- pValue :: a
}
payloadDecoder :: Value a -> Row (Payload a)
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))
getCount :: Session Int64
incrementAttempts :: Int -> [PayloadId] -> Session ()
newtype QueryException = QueryException QueryError
runThrow :: Session a -> Connection -> IO a
execute :: Connection -> ByteString -> IO ()
notifyPayload :: ByteString -> Connection -> IO ()
data WithNotifyHandlers = WithNotifyHandlers {
- withNotifyHandlersAfterAction :: IO ()
- withNotifyHandlersBeforeNotification :: IO ()
}
data NoRows = NoRows
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 :: Value a -> Maybe PayloadId -> Int -> Session [(PayloadId, a)]
withDequeue :: Value a -> Int -> Int -> ([a] -> IO b) -> Session (Maybe b)
delete :: [PayloadId] -> Session ()

Documentation

data State Source #

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 Source #
Instance details Defined in Hasql.Queue.Internal Methods minBound :: State # maxBound :: State #
Enum State Source #
Instance details 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 Source #
Instance details Defined in Hasql.Queue.Internal Methods (==) :: State -> State -> Bool # (/=) :: State -> State -> Bool #
Ord State Source #
Instance details 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 Source #
Instance details 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 Source #

stateDecoder :: Value State Source #

stateEncoder :: Value State Source #

initialPayloadId :: PayloadId Source #

newtype PayloadId Source #

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

Constructors

PayloadId
Fields unPayloadId :: Int64

Instances

Eq PayloadId Source #
Instance details Defined in Hasql.Queue.Internal Methods (==) :: PayloadId -> PayloadId -> Bool # (/=) :: PayloadId -> PayloadId -> Bool #
Show PayloadId Source #
Instance details Defined in Hasql.Queue.Internal Methods showsPrec :: Int -> PayloadId -> ShowS # show :: PayloadId -> String # showList :: [PayloadId] -> ShowS #

data Payload a Source #

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) Source #
Instance details Defined in Hasql.Queue.Internal Methods (==) :: Payload a -> Payload a -> Bool # (/=) :: Payload a -> Payload a -> Bool #
Show a => Show (Payload a) Source #
Instance details 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) Source #

Payload decoder

payloadIdEncoder :: Value PayloadId Source #

payloadIdDecoder :: Value PayloadId Source #

payloadIdRow :: Row PayloadId Source #

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

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

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

Get the Payload given a PayloadId

getCount :: Session Int64 Source #

Get the number of rows in the Enqueued state.

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

newtype QueryException Source #

Constructors

QueryException QueryError

Instances

Eq QueryException Source #
Instance details Defined in Hasql.Queue.Internal Methods (==) :: QueryException -> QueryException -> Bool # (/=) :: QueryException -> QueryException -> Bool #
Show QueryException Source #
Instance details Defined in Hasql.Queue.Internal Methods showsPrec :: Int -> QueryException -> ShowS # show :: QueryException -> String # showList :: [QueryException] -> ShowS #
Exception QueryException Source #
Instance details Defined in Hasql.Queue.Internal Methods toException :: QueryException -> SomeException # fromException :: SomeException -> Maybe QueryException # displayException :: QueryException -> String #

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

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

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

data WithNotifyHandlers Source #

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 Source #
Instance details Defined in Hasql.Queue.Internal Methods (<>) :: WithNotifyHandlers -> WithNotifyHandlers -> WithNotifyHandlers # sconcat :: NonEmpty WithNotifyHandlers -> WithNotifyHandlers # stimes :: Integral b => b -> WithNotifyHandlers -> WithNotifyHandlers #
Monoid WithNotifyHandlers Source #
Instance details Defined in Hasql.Queue.Internal Methods mempty :: WithNotifyHandlers # mappend :: WithNotifyHandlers -> WithNotifyHandlers -> WithNotifyHandlers # mconcat :: [WithNotifyHandlers] -> WithNotifyHandlers #

data NoRows Source #

Constructors

NoRows

Instances

Eq NoRows Source #
Instance details Defined in Hasql.Queue.Internal Methods (==) :: NoRows -> NoRows -> Bool # (/=) :: NoRows -> NoRows -> Bool #
Show NoRows Source #
Instance details Defined in Hasql.Queue.Internal Methods showsPrec :: Int -> NoRows -> ShowS # show :: NoRows -> String # showList :: [NoRows] -> ShowS #
Exception NoRows Source #
Instance details Defined in Hasql.Queue.Internal Methods toException :: NoRows -> SomeException # fromException :: SomeException -> Maybe NoRows # displayException :: NoRows -> String #

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

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

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

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

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

failures Source #

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) Source #

delete :: [PayloadId] -> Session () Source #