Data.ConnectionPool.Class

Type class for common connection pool operations.

Documentation

class ConnectionPoolFor protocol where

Type class for common connection pool operations. It intentionally doesn't handle connection pool creation, which is best left to dedicated smart constructors.

Since version 0.2.

Minimal complete definition

withConnection, tryWithConnection, destroyAllConnections

Associated Types

type HandlerData protocol

Data passed to individual connection handler.

Methods

withConnection :: MonadBaseControl IO m => ConnectionPool protocol -> (HandlerData protocol -> m r) -> m r

Temporarily take a connection from a pool, run handler with it, and return it to the pool afterwards.

Since version 0.2.

tryWithConnection :: MonadBaseControl IO m => ConnectionPool protocol -> (HandlerData protocol -> m r) -> m (Maybe r)

Similar to withConnection, but only performs action if a connection could be taken from the pool without blocking. Otherwise, tryWithResource returns immediately with Nothing (ie. the action function is not called). Conversely, if a connection can be acquired from the pool without blocking, the action is performed and it's result is returned, wrapped in a Just.

Since version 0.2.

destroyAllConnections :: ConnectionPool protocol -> IO ()

Destroy all connections that might be still open in a connection pool. This is useful when one needs to release all resources at once and not to wait for idle timeout to be reached.

Since version 0.2.

Instances

ConnectionPoolFor * TcpClient

Defined using:

withConnection = withTcpClientConnection
destroyAllConnections = destroyAllTcpClientConnections

Since version 0.2.

Associated Types

type HandlerData TcpClient (protocol :: TcpClient) :: *

Methods

withConnection :: MonadBaseControl IO m => ConnectionPool TcpClient protocol -> (HandlerData TcpClient protocol -> m r) -> m r

tryWithConnection :: MonadBaseControl IO m => ConnectionPool TcpClient protocol -> (HandlerData TcpClient protocol -> m r) -> m (Maybe r)

destroyAllConnections :: ConnectionPool TcpClient protocol -> IO ()

ConnectionPoolFor * UnixClient

Defined using:

withConnection = withUnixClientConnection
destroyAllConnections = destroyAllUnixClientConnections

Since version 0.2.

Associated Types

type HandlerData UnixClient (protocol :: UnixClient) :: *

Methods

withConnection :: MonadBaseControl IO m => ConnectionPool UnixClient protocol -> (HandlerData UnixClient protocol -> m r) -> m r

tryWithConnection :: MonadBaseControl IO m => ConnectionPool UnixClient protocol -> (HandlerData UnixClient protocol -> m r) -> m (Maybe r)

destroyAllConnections :: ConnectionPool UnixClient protocol -> IO ()