Safe Haskell	None
Language	GHC2024

Arbiter.Hasql.MonadArbiter

Contents

MonadArbiter implementation
Connection pool management

Description

hasql implementation helpers for MonadArbiter.

Handlers receive a Hasql.Connection.Connection for running typed hasql queries inside the worker transaction:

import Arbiter.Hasql.MonadArbiter
import Hasql.Connection qualified as Hasql

instance MonadArbiter MyApp where
  type Handler MyApp jobs result = Hasql.Connection -> jobs -> MyApp result
  executeQuery             = hasqlExecuteQuery
  executeStatement         = hasqlExecuteStatement
  withDbTransaction        = hasqlWithDbTransaction
  runHandlerWithConnection = hasqlRunHandlerWithConnection

Synopsis

hasqlExecuteQuery :: (HasHasqlPool m, MonadIO m) => Text -> Params -> RowCodec a -> m [a]
hasqlExecuteStatement :: (HasHasqlPool m, MonadIO m) => Text -> Params -> m Int64
hasqlWithDbTransaction :: (HasHasqlPool m, MonadUnliftIO m) => m a -> m a
hasqlRunHandlerWithConnection :: (HasHasqlPool m, MonadIO m) => (Connection -> jobs -> m result) -> jobs -> m result
data HasqlConnectionPool = HasqlConnectionPool {
- connectionPool :: Maybe (Pool Connection)
- activeConn :: Maybe Connection
- transactionDepth :: Int
}
class Monad m => HasHasqlPool (m :: Type -> Type) where
- getHasqlPool :: m HasqlConnectionPool
- localHasqlPool :: (HasqlConnectionPool -> HasqlConnectionPool) -> m a -> m a
localHasqlConnection :: HasHasqlPool m => Connection -> m a -> m a

MonadArbiter implementation

hasqlExecuteQuery :: (HasHasqlPool m, MonadIO m) => Text -> Params -> RowCodec a -> m [a] Source #

hasqlExecuteStatement :: (HasHasqlPool m, MonadIO m) => Text -> Params -> m Int64 Source #

hasqlWithDbTransaction :: (HasHasqlPool m, MonadUnliftIO m) => m a -> m a Source #

Run a block of code within a database transaction.

Supports nested transactions via savepoints, matching arbiter-simple.

hasqlRunHandlerWithConnection :: (HasHasqlPool m, MonadIO m) => (Connection -> jobs -> m result) -> jobs -> m result Source #

Invoke a handler by passing the active hasql connection.

The handler receives a Hasql.Connection so it can run typed hasql queries within the worker transaction.

Connection pool management

data HasqlConnectionPool Source #

Connection pool state for hasql connections.

Mirrors SimpleConnectionPool from arbiter-simple.

Constructors

HasqlConnectionPool
Fields connectionPool :: Maybe (Pool Connection) The underlying resource pool. `Nothing` when using connection-only mode via `inTransaction`. activeConn :: Maybe Connection Pinned connection when inside a transaction transactionDepth :: Int Current nesting depth (0 = no active transaction)

class Monad m => HasHasqlPool (m :: Type -> Type) where Source #

Typeclass for monads that carry a hasql connection pool.

Methods

getHasqlPool :: m HasqlConnectionPool Source #

localHasqlPool :: (HasqlConnectionPool -> HasqlConnectionPool) -> m a -> m a Source #

Instances

Instances details

Monad m => HasHasqlPool (HasqlDb registry m) Source #
Instance details Defined in Arbiter.Hasql.HasqlDb Methods getHasqlPool :: HasqlDb registry m HasqlConnectionPool Source # localHasqlPool :: (HasqlConnectionPool -> HasqlConnectionPool) -> HasqlDb registry m a -> HasqlDb registry m a Source #

localHasqlConnection :: HasHasqlPool m => Connection -> m a -> m a Source #

Pin a hasql connection for transactional work.

All arbiter operations within the callback will use this connection. The caller must have already issued BEGIN on the connection.