Safe Haskell	None
Language	GHC2024

Arbiter.Core.Listen

Description

Backend-agnostic LISTEN/NOTIFY hub over one connection per env.

Synopsis

data Notification = Notification {
- notificationChannel :: ByteString
- notificationData :: ByteString
}
data ListenConn = ListenConn {
- listenNotifies :: IO (Maybe Notification)
- listenSocket :: IO (Maybe Fd)
- listenConsumeInput :: IO Bool
- listenExec :: ByteString -> IO (Either Text ())
- listenEscapeIdentifier :: ByteString -> IO (Maybe ByteString)
}
data Listener
data HubLog = HubLog {
- hubRecovered :: Text -> IO ()
- hubWarn :: Text -> IO ()
- hubError :: Text -> IO ()
- hubRepeatInterval :: NominalDiffTime
}
withChannels :: MonadUnliftIO m => Listener -> HubLog -> [(ByteString, Notification -> m ())] -> (STM Bool -> m a) -> m a
newListener :: ((ListenConn -> IO ()) -> IO ()) -> IO Listener

Documentation

data NotificationSource #

A received notification. The channel it arrived on and its payload.

Constructors

Notification
Fields notificationChannel :: ByteString The channel name. notificationData :: ByteString The payload. Empty when the sender gave none.

Instances

Instances details

Eq Notification Source #
Instance details Defined in Arbiter.Core.Listen Methods (==) :: Notification -> Notification -> Bool# (/=) :: Notification -> Notification -> Bool#
Show Notification Source #
Instance details Defined in Arbiter.Core.Listen Methods showsPrec :: Int -> Notification -> ShowS# show :: Notification -> String# showList :: [Notification] -> ShowS#

data ListenConnSource #

The connection operations the hub loop needs.

Constructors

ListenConn

Fields

listenNotifies :: IO (Maybe Notification)
The next pending notification. Nothing when none is pending.
listenSocket :: IO (Maybe Fd)
The connection's socket. Nothing fails the connection, and the hub reconnects.
listenConsumeInput :: IO Bool
Read input from the socket. False fails the connection, and the hub reconnects.
listenExec :: ByteString -> IO (Either Text ())
Run a command. A failure comes back as its reason.
listenEscapeIdentifier :: ByteString -> IO (Maybe ByteString)
Quote a channel name. Nothing falls back to quoteIdentifier.

data ListenerSource #

Handle to an environment's shared, refcounted LISTEN hub slot.

data HubLogSource #

Hub event reporting preferences for a registrant.

Constructors

HubLog
Fields hubRecovered :: Text -> IO () The hub's connection came back. hubWarn :: Text -> IO () This registrant's own channel handler raised. hubError :: Text -> IO () The hub's connection failed. hubRepeatInterval :: NominalDiffTime Repeat interval for a persistent connection failure.

withChannels :: MonadUnliftIO m => Listener -> HubLog -> [(ByteString, Notification -> m ())] -> (STM Bool -> m a) -> m aSource #

Register the caller's channels on the env's shared hub for the duration of the body. The STM action reports True while they are all subscribed. A reconnect resets it.

newListener :: ((ListenConn -> IO ()) -> IO ()) -> IO ListenerSource #

A Listener with a fresh hub slot over a connection runner.