Database.PostgreSQL.Config

Types

data PostgresConf

Configuration parsed from json or yaml file, or obtained by any other way. Example configuration yml is:

database:    "dbname"
host:        "127.0.0.1"        # optional
port:        "5432"             # optional
user:        "dbuser"
password:    "pass"
poolsize:    "10"               # optional maximum connections in pool
pooltimeout: "60"               # optional minimum connection lifetime
poolstripes: "1"                # optional count of stripes in pool

Constructors

PostgresConf

Fields

pgConnStr :: ByteString

The connection string.

pgPoolSize :: Int

How many connections should be held on the connection pool.

pgPoolTimeout :: NominalDiffTime

Timeout to stay connection active

pgPoolStripes :: Int

Stripes in the pool

Instances

Eq PostgresConf

Ord PostgresConf

Show PostgresConf

FromJSON PostgresConf

newtype PGPool

Connection pool. Must be created from settings using createPGPool

Constructors

PGPool

Fields

unPGPool :: Pool Connection

Instances

Show PGPool

Generic PGPool

type Rep PGPool

Pool creation

createPGPool :: PostgresConf -> IO PGPool

Create pool from parsed configuration

type PGCallback = Connection -> IO ()

createPGPoolWithCallback

Arguments

:: PostgresConf

connection data

-> PGCallback

callback action, can be used for performing arbitrary action on connection

-> IO PGPool

Create pool from parsed configuration, which enables to fire a callback after creating each connection.

pingPGPool :: PGPool -> IO ()

Force to create at least one connection in pool. Usefull to check connection settings at program start time

Helpers for postgresql-query

withPGPool :: (MonadReader site m, MonadBaseControl IO m) => (site -> PGPool) -> (Connection -> m a) -> m a

Combinator for simple implementation of withPGConnection method from package postgresql-query. Typical usage is:

instance HasPostgres (HandlerT App IO) where
    withPGConnection = withPGPool appPGPool

withPGPoolPrim :: MonadBaseControl IO m => m PGPool -> (Connection -> m a) -> m a

Another combinator to implement withPGConnection

instance HasPostgres (OurMonadT IO) where
    withPGConnection = withPGPoolPrim $ getPGPool <$> getSomeThing