The withResilientConnection function gives us a ResilientConnection from which we can always get a health connection, while automatic reconnection with retries and exponential back-offs are being handled in the background.

import           Database.PostgreSQL.Resilient
import qualified Database.PostgreSQL.Simple    as P

withResilientConnection defaultResilientSettings logHandler connectInfo $ pool ->
  (conn :: P.Connection) <- getConnection pool
  res <- P.query_ conn "SELECT * FROM foo"
  putStrLn $ show res

logHandler :: String -> IO ()
logHandler = putStrLn

connectInfo :: P.ConnectInfo
connectInfo = P.ConnectInfo
  { P.connectHost     = "localhost"
  , P.connectPort     = 5432
  , P.connectUser     = "postgres"
  , P.connectPassword = ""
  , P.connectDatabase = "store"
  }

defaultResilientSettings :: ResilientSettings
defaultResilientSettings = ResilientSettings
  { healthCheckEvery     = 3
  , exponentialBackoffThreshold = 10
  }