-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | Pool of connections for Hasql
--   
--   Pool of connections for Hasql
@package hasql-pool
@version 0.9

module Hasql.Pool

-- | Pool of connections to DB.
data Pool

-- | Create a connection-pool, with default settings.
--   
--   No connections actually get established by this function. It is
--   delegated to <a>use</a>.
acquire :: Int -> DiffTime -> DiffTime -> Settings -> IO Pool

-- | Create a connection-pool.
--   
--   In difference to <a>acquire</a> new connection settings get fetched
--   each time a connection is created. This may be useful for some
--   security models.
--   
--   No connections actually get established by this function. It is
--   delegated to <a>use</a>.
acquireDynamically :: Int -> DiffTime -> DiffTime -> IO Settings -> IO Pool

-- | Use a connection from the pool to run a session and return the
--   connection to the pool, when finished.
--   
--   Session failing with a <a>ClientError</a> gets interpreted as a loss
--   of connection. In such case the connection does not get returned to
--   the pool and a slot gets freed up for a new connection to be
--   established the next time one is needed. The error still gets returned
--   from this function.
use :: Pool -> Session a -> IO (Either UsageError a)

-- | Release all the idle connections in the pool, and mark the in-use
--   connections to be released after use. Any connections acquired after
--   the call will be freshly established.
--   
--   The pool remains usable after this action. So you can use this
--   function to reset the connections in the pool. Naturally, you can also
--   use it to release the resources.
release :: Pool -> IO ()

-- | Union over all errors that <a>use</a> can result in.
data UsageError

-- | Attempt to establish a connection failed.
ConnectionUsageError :: ConnectionError -> UsageError

-- | Session execution failed.
SessionUsageError :: QueryError -> UsageError

-- | Timeout acquiring a connection.
AcquisitionTimeoutUsageError :: UsageError
instance GHC.Classes.Eq Hasql.Pool.UsageError
instance GHC.Show.Show Hasql.Pool.UsageError
instance GHC.Exception.Type.Exception Hasql.Pool.UsageError