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hasql-pool 0.8.0.7 → 1.4.2

raw patch · 28 files changed

Files

CHANGELOG.md view
@@ -1,3 +1,45 @@+# 1.4++- Migrated to `hasql-1.10`+- Updated connection settings API to use monoid-based `Settings` instead of list-based `[Setting]`+- Updated error types to use `Hasql.Errors` module instead of `Hasql.Session` and `Hasql.Connection`+- Changed session execution API from `Session.run session connection` to `Connection.use connection session`+- Error handling now uses `ConnectionSessionError` for connection-level issues instead of `ClientError`+- Updated statement construction to use `Statement.preparable` and `Statement.unpreparable` instead of direct constructor+- Hid the `Defaults` module from the public API++# 1.3++- Adapt to the new settings model of `hasql-1.9`++# 1.2++- Migrated to `hasql-1.7`+- Changed references to `QueryError` in observations to `SessionError`++# 1.1++- `ReadyForUseConnectionStatus` got extended with the `ConnectionReadyForUseReason` details.+- `initSession` setting added.++# 1++- Optional observability event stream added. Provides a flexible mechanism for monitoring the healthiness of the pool via logs and metrics.+- Configuration got isolated into a DSL, which will allow to provide new configurations without breaking backward compatibility.++# 0.10.1++- Avoid releasing connections on exceptions thrown in session++# 0.9++- Maximal lifetime added for connections. Allows to refresh the connections in time cleaning up the resources.++Breaking:++- The acquisition timeout is now non-optional.+- Moved to `DiffTime` for timeouts.+ # 0.8.0.7  Fix excessive connections during releases due to race conditions.
+ diagrams-output/connection-status-model.png view

binary file changed (absent → 16434 bytes)

hasql-pool.cabal view
@@ -1,8 +1,6 @@ cabal-version: 3.0- name: hasql-pool-version: 0.8.0.7-+version: 1.4.2 category: Hasql, Database, PostgreSQL synopsis: Pool of connections for Hasql homepage: https://github.com/nikita-volkov/hasql-pool@@ -12,39 +10,122 @@ copyright: (c) 2015, Nikita Volkov license: MIT license-file: LICENSE-extra-source-files: CHANGELOG.md+extra-source-files:+  CHANGELOG.md+  diagrams-output/*.png +extra-doc-files:+  diagrams-output/*.png+ source-repository head   type: git-  location: git://github.com/nikita-volkov/hasql-pool.git+  location: https://github.com/nikita-volkov/hasql-pool  common base-settings-  default-extensions: BangPatterns, BlockArguments, ConstraintKinds, DataKinds, DefaultSignatures, DeriveDataTypeable, DeriveFoldable, DeriveFunctor, DeriveGeneric, DerivingVia, DeriveTraversable, EmptyDataDecls, FlexibleContexts, FlexibleInstances, FunctionalDependencies, GADTs, GeneralizedNewtypeDeriving, InstanceSigs, LambdaCase, LiberalTypeSynonyms, MagicHash, MultiParamTypeClasses, MultiWayIf, NoImplicitPrelude, NoMonomorphismRestriction, OverloadedStrings, PatternGuards, ParallelListComp, QuasiQuotes, RankNTypes, RecordWildCards, ScopedTypeVariables, StandaloneDeriving, StrictData, TemplateHaskell, TupleSections, TypeApplications, TypeFamilies, TypeOperators, UnboxedTuples   default-language: Haskell2010+  default-extensions:+    ApplicativeDo+    Arrows+    BangPatterns+    BlockArguments+    ConstraintKinds+    DataKinds+    DefaultSignatures+    DeriveDataTypeable+    DeriveFoldable+    DeriveFunctor+    DeriveGeneric+    DeriveTraversable+    DerivingVia+    EmptyDataDecls+    FlexibleContexts+    FlexibleInstances+    FunctionalDependencies+    GADTs+    GeneralizedNewtypeDeriving+    ImportQualifiedPost+    LambdaCase+    LiberalTypeSynonyms+    MultiParamTypeClasses+    MultiWayIf+    NoImplicitPrelude+    NoMonomorphismRestriction+    NumericUnderscores+    OverloadedStrings+    PatternGuards+    QuasiQuotes+    RankNTypes+    RecordWildCards+    RoleAnnotations+    ScopedTypeVariables+    StandaloneDeriving+    StrictData+    TupleSections+    TypeApplications+    TypeFamilies+    TypeOperators  library   import: base-settings-  hs-source-dirs: library+  hs-source-dirs:+    src/library/exposed+    src/library/other++  -- cabal-gild: discover src/library/exposed   exposed-modules:     Hasql.Pool+    Hasql.Pool.Config+    Hasql.Pool.Config.Defaults+    Hasql.Pool.Observation++  -- cabal-gild: discover src/library/other   other-modules:+    Hasql.Pool.Config.Config+    Hasql.Pool.Config.Setting     Hasql.Pool.Prelude+    Hasql.Pool.SessionErrorDestructors+   build-depends:     base >=4.11 && <5,-    hasql >=1.6.0.1 && <1.7,+    bytestring >=0.10 && <0.14,+    hasql >=1.10 && <1.11,     stm >=2.5 && <3,-    transformers >=0.5 && <0.7,+    text >=1.2 && <3,+    time >=1.9 && <2,+    uuid >=1.3 && <2,  test-suite test   import: base-settings   type: exitcode-stdio-1.0-  hs-source-dirs: test+  hs-source-dirs: src/integration-tests   main-is: Main.hs+  other-modules:+    Helpers.Hooks+    Helpers.Scripts+    Helpers.Sessions+    Specs.BySubject.Config.AgingTimeoutSpec+    Specs.BySubject.Config.IdlenessTimeoutSpec+    Specs.BySubject.Config.InitSessionSpec+    Specs.BySubject.Helpers.Sessions.CountConnectionsSpec+    Specs.BySubject.Helpers.Sessions.GetSettingSpec+    Specs.BySubject.ReleaseSpec+    Specs.BySubject.SpecHook+    Specs.BySubject.UsageError.AcquisitionTimeoutSpec+    Specs.BySubject.UsageError.SessionSpec+    Specs.BySubject.UseSpec+   ghc-options: -threaded+  build-tool-depends:+    hspec-discover:hspec-discover ^>=2.11.12+   build-depends:     async >=2.2 && <3,     hasql,     hasql-pool,     hspec >=2.6 && <3,+    postgresql-libpq >=0.10 && <0.12,+    random >=1.2 && <2,     rerebase >=1.15 && <2,-    stm >=2.5 && <3,+    testcontainers-postgresql >=0.2 && <0.3,+    text-builder >=1 && <1.1,+    tuple ^>=0.3.0.2,
− library/Hasql/Pool.hs 
@@ -1,171 +0,0 @@-module Hasql.Pool-  ( -- * Pool-    Pool,-    acquire,-    acquireDynamically,-    release,-    use,--    -- * Errors-    UsageError (..),-  )-where--import Hasql.Connection (Connection)-import qualified Hasql.Connection as Connection-import Hasql.Pool.Prelude-import Hasql.Session (Session)-import qualified Hasql.Session as Session---- | Pool of connections to DB.-data Pool = Pool-  { -- | Connection settings.-    poolFetchConnectionSettings :: IO Connection.Settings,-    -- | Acquisition timeout, in microseconds.-    poolAcquisitionTimeout :: Maybe Int,-    -- | Avail connections.-    poolConnectionQueue :: TQueue Connection,-    -- | Remaining capacity.-    -- The pool size limits the sum of poolCapacity, the length-    -- of poolConnectionQueue and the number of in-flight-    -- connections.-    poolCapacity :: TVar Int,-    -- | Whether to return a connection to the pool.-    poolReuse :: TVar (TVar Bool)-  }---- | Create a connection-pool.------ No connections actually get established by this function. It is delegated--- to 'use'.-acquire ::-  -- | Pool size.-  Int ->-  -- | Connection acquisition timeout in microseconds.-  Maybe Int ->-  -- | Connection settings.-  Connection.Settings ->-  IO Pool-acquire poolSize timeout connectionSettings =-  acquireDynamically poolSize timeout (pure connectionSettings)---- | Create a connection-pool.------ In difference to 'acquire' new 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 'use'.-acquireDynamically ::-  -- | Pool size.-  Int ->-  -- | Connection acquisition timeout in microseconds.-  Maybe Int ->-  -- | Action fetching connection settings.-  IO Connection.Settings ->-  IO Pool-acquireDynamically poolSize timeout fetchConnectionSettings = do-  Pool fetchConnectionSettings timeout-    <$> newTQueueIO-    <*> newTVarIO poolSize-    <*> (newTVarIO =<< newTVarIO True)---- | 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 ()-release Pool {..} =-  join . atomically $ do-    prevReuse <- readTVar poolReuse-    writeTVar prevReuse False-    newReuse <- newTVar True-    writeTVar poolReuse newReuse-    conns <- flushTQueue poolConnectionQueue-    return $ forM_ conns $ \conn -> do-      Connection.release conn-      atomically $ modifyTVar' poolCapacity succ---- | Use a connection from the pool to run a session and return the connection--- to the pool, when finished.------ Session failing with a 'Session.ClientError' 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.Session a -> IO (Either UsageError a)-use Pool {..} sess = do-  timeout <- case poolAcquisitionTimeout of-    Just delta -> do-      delay <- registerDelay delta-      return $ readTVar delay-    Nothing ->-      return $ return False-  join . atomically $ do-    reuseVar <- readTVar poolReuse-    asum-      [ readTQueue poolConnectionQueue <&> onConn reuseVar,-        do-          capVal <- readTVar poolCapacity-          if capVal > 0-            then do-              writeTVar poolCapacity $! pred capVal-              return $ onNewConn reuseVar-            else retry,-        do-          timedOut <- timeout-          if timedOut-            then return . return . Left $ AcquisitionTimeoutUsageError-            else retry-      ]-  where-    onNewConn reuseVar = do-      settings <- poolFetchConnectionSettings-      connRes <- Connection.acquire settings-      case connRes of-        Left connErr -> do-          atomically $ modifyTVar' poolCapacity succ-          return $ Left $ ConnectionUsageError connErr-        Right conn -> onConn reuseVar conn-    onConn reuseVar conn = do-      sessRes <--        catch (Session.run sess conn) $ \(err :: SomeException) -> do-          Connection.release conn-          atomically $ modifyTVar' poolCapacity succ-          throw err--      case sessRes of-        Left err -> case err of-          Session.QueryError _ _ (Session.ClientError _) -> do-            atomically $ modifyTVar' poolCapacity succ-            return $ Left $ SessionUsageError err-          _ -> do-            returnConn-            return $ Left $ SessionUsageError err-        Right res -> do-          returnConn-          return $ Right res-      where-        returnConn =-          join . atomically $ do-            reuse <- readTVar reuseVar-            if reuse-              then writeTQueue poolConnectionQueue conn $> return ()-              else return $ do-                Connection.release conn-                atomically $ modifyTVar' poolCapacity succ---- | Union over all errors that 'use' can result in.-data UsageError-  = -- | Attempt to establish a connection failed.-    ConnectionUsageError Connection.ConnectionError-  | -- | Session execution failed.-    SessionUsageError Session.QueryError-  | -- | Timeout acquiring a connection.-    AcquisitionTimeoutUsageError-  deriving (Show, Eq)--instance Exception UsageError
− library/Hasql/Pool/Prelude.hs 
@@ -1,79 +0,0 @@-module Hasql.Pool.Prelude-  ( module Exports,-  )-where--import Control.Applicative as Exports hiding (WrappedArrow (..))-import Control.Arrow as Exports hiding (first, second)-import Control.Category as Exports-import Control.Concurrent as Exports-import Control.Concurrent.STM as Exports hiding (orElse)-import Control.Exception as Exports-import Control.Monad as Exports hiding (fail, forM, forM_, mapM, mapM_, msum, sequence, sequence_)-import Control.Monad.Fail as Exports-import Control.Monad.Fix as Exports hiding (fix)-import Control.Monad.IO.Class as Exports-import Control.Monad.ST as Exports-import Control.Monad.Trans.Class as Exports-import Control.Monad.Trans.Cont as Exports hiding (callCC, shift)-import Control.Monad.Trans.Except as Exports (Except, ExceptT (ExceptT), except, mapExcept, mapExceptT, runExcept, runExceptT, withExcept, withExceptT)-import Control.Monad.Trans.Maybe as Exports-import Control.Monad.Trans.Reader as Exports (Reader, ReaderT (ReaderT), mapReader, mapReaderT, runReader, runReaderT, withReader, withReaderT)-import Control.Monad.Trans.State.Strict as Exports (State, StateT (StateT), evalState, evalStateT, execState, execStateT, mapState, mapStateT, runState, runStateT, withState, withStateT)-import Control.Monad.Trans.Writer.Strict as Exports (Writer, WriterT (..), execWriter, execWriterT, mapWriter, mapWriterT, runWriter)-import Data.Bifunctor as Exports-import Data.Bits as Exports-import Data.Bool as Exports-import Data.Char as Exports-import Data.Coerce as Exports-import Data.Complex as Exports-import Data.Data as Exports-import Data.Dynamic as Exports-import Data.Either as Exports-import Data.Fixed as Exports-import Data.Foldable as Exports hiding (toList)-import Data.Function as Exports hiding (id, (.))-import Data.Functor as Exports-import Data.Functor.Compose as Exports-import Data.IORef as Exports-import Data.Int as Exports-import Data.Ix as Exports-import Data.List as Exports hiding (all, and, any, concat, concatMap, elem, find, foldl, foldl', foldl1, foldr, foldr1, isSubsequenceOf, mapAccumL, mapAccumR, maximum, maximumBy, minimum, minimumBy, notElem, or, product, sortOn, sum, uncons)-import Data.List.NonEmpty as Exports (NonEmpty (..))-import Data.Maybe as Exports-import Data.Monoid as Exports hiding (Alt)-import Data.Ord as Exports-import Data.Proxy as Exports-import Data.Ratio as Exports-import Data.STRef as Exports-import Data.String as Exports-import Data.Traversable as Exports-import Data.Tuple as Exports-import Data.Unique as Exports-import Data.Version as Exports-import Data.Void as Exports-import Data.Word as Exports-import Debug.Trace as Exports-import Foreign.ForeignPtr as Exports-import Foreign.Ptr as Exports-import Foreign.StablePtr as Exports-import Foreign.Storable as Exports-import GHC.Conc as Exports hiding (orElse, threadWaitRead, threadWaitReadSTM, threadWaitWrite, threadWaitWriteSTM, withMVar)-import GHC.Exts as Exports (IsList (..), groupWith, inline, lazy, sortWith)-import GHC.Generics as Exports (Generic)-import GHC.IO.Exception as Exports-import Numeric as Exports-import System.Environment as Exports-import System.Exit as Exports-import System.IO as Exports (Handle, hClose)-import System.IO.Error as Exports-import System.IO.Unsafe as Exports-import System.Mem as Exports-import System.Mem.StableName as Exports-import System.Timeout as Exports-import Text.ParserCombinators.ReadP as Exports (ReadP, ReadS, readP_to_S, readS_to_P)-import Text.ParserCombinators.ReadPrec as Exports (ReadPrec, readP_to_Prec, readPrec_to_P, readPrec_to_S, readS_to_Prec)-import Text.Printf as Exports (hPrintf, printf)-import Text.Read as Exports (Read (..), readEither, readMaybe)-import Unsafe.Coerce as Exports-import Prelude as Exports hiding (all, and, any, concat, concatMap, elem, fail, foldl, foldl1, foldr, foldr1, id, mapM, mapM_, maximum, minimum, notElem, or, product, sequence, sequence_, sum, (.))
+ src/integration-tests/Helpers/Hooks.hs view
@@ -0,0 +1,19 @@+-- | Hooks for Hspec.+module Helpers.Hooks where++import Data.Bool+import TestcontainersPostgresql qualified+import Prelude hiding (Handler)++-- | Testing action in the scope of the host name and port of a running fresh isolated postgres server.+type Handler = (Text, Word16) -> IO ()++postgres17 :: Handler -> IO ()+postgres17 handler =+  TestcontainersPostgresql.run+    TestcontainersPostgresql.Config+      { forwardLogs = False,+        tagName = "postgres:17",+        auth = TestcontainersPostgresql.TrustAuth+      }+    (\(host, portInt) -> handler (host, fromIntegral portInt))
+ src/integration-tests/Helpers/Scripts.hs view
@@ -0,0 +1,72 @@+module Helpers.Scripts where++import Hasql.Connection.Settings qualified as Connection.Settings+import Hasql.Pool qualified as Pool+import Hasql.Pool.Config qualified as Config+import System.Random.Stateful qualified as Random+import TextBuilder qualified+import Prelude++-- |+-- Parameters provided by the scope.+-- Host and port of a running isolated postgres server.+type ScopeParams = (Text, Word16)++onTaggedPool :: Int -> DiffTime -> DiffTime -> DiffTime -> Text -> ScopeParams -> (Pool.Pool -> IO ()) -> IO ()+onTaggedPool poolSize acqTimeout maxLifetime maxIdletime appName (host, port) =+  bracket+    ( Pool.acquire+        ( Config.settings+            [ Config.size poolSize,+              Config.acquisitionTimeout acqTimeout,+              Config.agingTimeout maxLifetime,+              Config.idlenessTimeout maxIdletime,+              Config.staticConnectionSettings+                ( mconcat+                    [ Connection.Settings.hostAndPort host (fromIntegral port),+                      Connection.Settings.user "postgres",+                      Connection.Settings.password "",+                      Connection.Settings.dbname "postgres",+                      Connection.Settings.applicationName appName+                    ]+                )+            ]+        )+    )+    Pool.release++onAutotaggedPool :: Int -> DiffTime -> DiffTime -> DiffTime -> ScopeParams -> (Text -> Pool.Pool -> IO ()) -> IO ()+onAutotaggedPool poolSize acqTimeout maxLifetime maxIdletime (host, port) cont = do+  -- Generate app name+  appName <- generateName "hasql-pool-test-"+  onTaggedPool poolSize acqTimeout maxLifetime maxIdletime appName (host, port) (cont appName)++onDefaultTaggedPool :: ScopeParams -> (Text -> Pool.Pool -> IO ()) -> IO ()+onDefaultTaggedPool =+  onAutotaggedPool 3 10 1_800 1_800++generateName :: Text -> IO Text+generateName prefix = do+  uniqueNum1 <- Random.uniformWord64 Random.globalStdGen+  uniqueNum2 <- Random.uniformWord64 Random.globalStdGen+  pure+    $ TextBuilder.toText+    $ mconcat+    $ [ TextBuilder.text prefix,+        TextBuilder.decimal uniqueNum1,+        "-",+        TextBuilder.decimal uniqueNum2+      ]++generateVarname :: IO Text+generateVarname = do+  uniqueNum1 <- Random.uniformWord64 Random.globalStdGen+  uniqueNum2 <- Random.uniformWord64 Random.globalStdGen+  pure+    $ TextBuilder.toText+    $ mconcat+    $ [ "testing.v",+        TextBuilder.decimal uniqueNum1,+        "v",+        TextBuilder.decimal uniqueNum2+      ]
+ src/integration-tests/Helpers/Sessions.hs view
@@ -0,0 +1,65 @@+module Helpers.Sessions+  ( selectOne,+    badQuery,+    closeConn,+    setSetting,+    getSetting,+    countConnections,+  )+where++import Data.Tuple.All+import Database.PostgreSQL.LibPQ qualified as Pq+import Hasql.Decoders qualified as Decoders+import Hasql.Encoders qualified as Encoders+import Hasql.Session qualified as Session+import Hasql.Statement qualified as Statement+import Prelude++selectOne :: Session.Session Int64+selectOne =+  Session.statement () statement+  where+    statement = Statement.preparable "SELECT 1::int8" Encoders.noParams decoder+    decoder = Decoders.singleRow (Decoders.column (Decoders.nonNullable Decoders.int8))++badQuery :: Session.Session ()+badQuery =+  Session.statement () statement+  where+    statement =+      Statement.preparable "zzz" Encoders.noParams Decoders.noResult++closeConn :: Session.Session ()+closeConn =+  Session.onLibpqConnection \conn -> do+    Pq.finish conn+    pure (Right (), conn)++setSetting :: Text -> Text -> Session.Session ()+setSetting name value = do+  Session.statement (name, value) statement+  where+    statement =+      Statement.preparable "SELECT set_config($1, $2, false)" encoder Decoders.noResult+    encoder =+      mconcat+        [ sel1 >$< Encoders.param (Encoders.nonNullable Encoders.text),+          sel2 >$< Encoders.param (Encoders.nonNullable Encoders.text)+        ]++getSetting :: Text -> Session.Session (Maybe Text)+getSetting name = do+  Session.statement name statement+  where+    statement = Statement.preparable "SELECT current_setting($1, true)" encoder decoder+    encoder = Encoders.param (Encoders.nonNullable Encoders.text)+    decoder = Decoders.singleRow (Decoders.column (Decoders.nullable Decoders.text))++countConnections :: Text -> Session.Session Int64+countConnections appName = do+  Session.statement appName statement+  where+    statement = Statement.preparable "SELECT count(*) FROM pg_stat_activity WHERE application_name = $1" encoder decoder+    encoder = Encoders.param (Encoders.nonNullable Encoders.text)+    decoder = Decoders.singleRow (Decoders.column (Decoders.nonNullable Decoders.int8))
+ src/integration-tests/Main.hs view
@@ -0,0 +1,1 @@+{-# OPTIONS_GHC -F -pgmF hspec-discover #-}
+ src/integration-tests/Specs/BySubject/Config/AgingTimeoutSpec.hs view
@@ -0,0 +1,32 @@+module Specs.BySubject.Config.AgingTimeoutSpec where++import Hasql.Pool+import Helpers.Scripts qualified as Scripts+import Helpers.Sessions qualified as Sessions+import Test.Hspec+import Prelude++spec :: SpecWith Scripts.ScopeParams+spec = do+  it "Actively times out old connections" \scopeParams -> do+    Scripts.onAutotaggedPool 3 10 1_800 1_800 scopeParams \_appName1 pool1 -> do+      Scripts.onAutotaggedPool 3 10 0.5 1_800 scopeParams \appName2 pool2 -> do+        res <- use pool2 $ Sessions.selectOne+        res `shouldBe` Right 1+        res2 <- use pool1 $ Sessions.countConnections appName2+        res2 `shouldBe` Right 1+        threadDelay 1_000_000 -- 1s+        res3 <- use pool1 $ Sessions.countConnections appName2+        res3 `shouldBe` Right 0++  it "Passively times out old connections" \scopeParams -> do+    -- 0.5s connection lifetime+    Scripts.onAutotaggedPool 1 10 0.5 1_800 scopeParams \_ pool -> do+      varName <- Scripts.generateVarname+      res <- use pool $ Sessions.setSetting varName "hello world"+      res `shouldBe` Right ()+      res2 <- use pool $ Sessions.getSetting varName+      res2 `shouldBe` Right (Just "hello world")+      threadDelay 1_000_000 -- 1s+      res3 <- use pool $ Sessions.getSetting varName+      res3 `shouldBe` Right Nothing
+ src/integration-tests/Specs/BySubject/Config/IdlenessTimeoutSpec.hs view
@@ -0,0 +1,29 @@+module Specs.BySubject.Config.IdlenessTimeoutSpec where++import Hasql.Pool+import Helpers.Scripts qualified as Scripts+import Helpers.Sessions qualified as Sessions+import Test.Hspec+import Prelude++spec :: SpecWith Scripts.ScopeParams+spec = do+  it "Times out old connections (maxIdletime)" \scopeParams -> do+    -- 0.5s connection idle time+    Scripts.onAutotaggedPool 1 10 1_800 0.5 scopeParams \_ pool -> do+      varName <- Scripts.generateVarname+      res <- use pool $ Sessions.setSetting varName "hello world"+      res `shouldBe` Right ()+      res2 <- use pool $ Sessions.getSetting varName+      res2 `shouldBe` Right (Just "hello world")+      -- busy sleep, to keep connection alive+      forM_ [1 :: Int .. 10] $ \_ -> do+        r <- use pool $ Sessions.selectOne+        r `shouldBe` Right 1+        threadDelay 100_000 -- 0.1s+      res3 <- use pool $ Sessions.getSetting varName+      res3 `shouldBe` Right (Just "hello world")+      -- idle sleep, connection times out+      threadDelay 1_000_000 -- 1s+      res4 <- use pool $ Sessions.getSetting varName+      res4 `shouldBe` Right Nothing
+ src/integration-tests/Specs/BySubject/Config/InitSessionSpec.hs view
@@ -0,0 +1,43 @@+module Specs.BySubject.Config.InitSessionSpec where++import Hasql.Pool+import Helpers.Scripts qualified as Scripts+import Helpers.Sessions qualified as Sessions+import Test.Hspec+import Prelude++spec :: SpecWith Scripts.ScopeParams+spec = do+  it "Persists after exceptions thrown in session" \scopeParams -> do+    Scripts.onAutotaggedPool 1 10 60 60 scopeParams \_ pool -> do+      varName <- Scripts.generateVarname++      res <- use pool do+        Sessions.setSetting varName "1"+        Sessions.getSetting varName+      shouldBe res (Right (Just "1"))++      try @SomeException do+        use pool do+          liftIO do+            throwIO (userError "Intentional error for testing")++      res <- use pool do+        Sessions.getSetting varName+      shouldBe res (Right (Just "1"))++  it "Persists after bad query" \scopeParams -> do+    Scripts.onAutotaggedPool 1 10 60 60 scopeParams \_ pool -> do+      varName <- Scripts.generateVarname++      res <- use pool do+        Sessions.setSetting varName "1"+        Sessions.getSetting varName+      shouldBe res (Right (Just "1"))++      use pool do+        Sessions.badQuery++      res <- use pool do+        Sessions.getSetting varName+      shouldBe res (Right (Just "1"))
+ src/integration-tests/Specs/BySubject/Helpers/Sessions/CountConnectionsSpec.hs view
@@ -0,0 +1,14 @@+module Specs.BySubject.Helpers.Sessions.CountConnectionsSpec where++import Hasql.Pool+import Helpers.Scripts qualified as Scripts+import Helpers.Sessions qualified as Sessions+import Test.Hspec+import Prelude++spec :: SpecWith Scripts.ScopeParams+spec = do+  it "Counts active connections" \scopeParams -> do+    Scripts.onAutotaggedPool 3 10 1_800 1_800 scopeParams \appName pool -> do+      res <- use pool $ Sessions.countConnections appName+      res `shouldBe` Right 1
+ src/integration-tests/Specs/BySubject/Helpers/Sessions/GetSettingSpec.hs view
@@ -0,0 +1,36 @@+module Specs.BySubject.Helpers.Sessions.GetSettingSpec where++import Hasql.Pool+import Helpers.Scripts qualified as Scripts+import Helpers.Sessions qualified as Sessions+import Test.Hspec+import Prelude++spec :: SpecWith Scripts.ScopeParams+spec = do+  it "Getting and setting session variables works" \scopeParams ->+    Scripts.onAutotaggedPool 1 10 1_800 1_800 scopeParams \_ pool -> do+      varName <- Scripts.generateVarname+      res <- use pool $ Sessions.getSetting varName+      res `shouldBe` Right Nothing+      res <- use pool $ do+        Sessions.setSetting varName "hello world"+        Sessions.getSetting varName+      res `shouldBe` Right (Just "hello world")++  it "Session variables stay set when a connection gets reused" \scopeParams ->+    Scripts.onAutotaggedPool 1 10 1_800 1_800 scopeParams \_ pool -> do+      varName <- Scripts.generateVarname+      res <- use pool $ Sessions.setSetting varName "hello world"+      res `shouldBe` Right ()+      res2 <- use pool $ Sessions.getSetting varName+      res2 `shouldBe` Right (Just "hello world")++  it "Releasing the pool resets session variables" \scopeParams -> do+    varName <- Scripts.generateVarname+    Scripts.onAutotaggedPool 1 10 1_800 1_800 scopeParams \_ pool -> do+      res <- use pool $ Sessions.setSetting varName "hello world"+      res `shouldBe` Right ()+      release pool+      res <- use pool $ Sessions.getSetting varName+      res `shouldBe` Right Nothing
+ src/integration-tests/Specs/BySubject/ReleaseSpec.hs view
@@ -0,0 +1,16 @@+module Specs.BySubject.ReleaseSpec where++import Hasql.Pool+import Helpers.Scripts qualified as Scripts+import Helpers.Sessions qualified as Sessions+import Test.Hspec+import Prelude++spec :: SpecWith Scripts.ScopeParams+spec = do+  it "The pool remains usable after release" \scopeParams ->+    Scripts.onAutotaggedPool 1 10 1_800 1_800 scopeParams \_ pool -> do+      _ <- use pool $ Sessions.selectOne+      release pool+      res <- use pool $ Sessions.selectOne+      shouldSatisfy res $ isRight
+ src/integration-tests/Specs/BySubject/SpecHook.hs view
@@ -0,0 +1,11 @@+-- Docs: https://hspec.github.io/hspec-discover.html+module Specs.BySubject.SpecHook where++import Helpers.Hooks qualified as Hooks+import Helpers.Scripts qualified as Scripts+import Test.Hspec+import Prelude++hook :: SpecWith Scripts.ScopeParams -> Spec+hook =+  aroundAll Hooks.postgres17 . parallel
+ src/integration-tests/Specs/BySubject/UsageError/AcquisitionTimeoutSpec.hs view
@@ -0,0 +1,33 @@+module Specs.BySubject.UsageError.AcquisitionTimeoutSpec where++import Control.Concurrent.Async (race)+import Hasql.Pool+import Helpers.Scripts qualified as Scripts+import Helpers.Sessions qualified as Sessions+import Test.Hspec+import Prelude++spec :: SpecWith Scripts.ScopeParams+spec = do+  it "Gets produced on timeout" \scopeParams ->+    -- 1ms timeout+    Scripts.onAutotaggedPool 1 0.001 1_800 1_800 scopeParams \_ pool -> do+      sleeping <- newEmptyMVar+      t0 <- getCurrentTime+      res <-+        race+          ( use pool+              $ liftIO+              $ do+                putMVar sleeping ()+                -- 1s+                threadDelay 1_000_000+          )+          ( do+              takeMVar sleeping+              use pool $ Sessions.selectOne+          )+      t1 <- getCurrentTime+      res `shouldBe` Right (Left AcquisitionTimeoutUsageError)+      -- 0.5s+      diffUTCTime t1 t0 `shouldSatisfy` (< 0.5)
+ src/integration-tests/Specs/BySubject/UsageError/SessionSpec.hs view
@@ -0,0 +1,16 @@+module Specs.BySubject.UsageError.SessionSpec where++import Hasql.Pool+import Helpers.Scripts qualified as Scripts+import Helpers.Sessions qualified as Sessions+import Test.Hspec+import Prelude++spec :: SpecWith Scripts.ScopeParams+spec = do+  it "Bad SQL query triggers error" \scopeParams ->+    Scripts.onAutotaggedPool 1 10 1_800 1_800 scopeParams \_ pool -> do+      res <- use pool Sessions.badQuery+      shouldSatisfy res $ \case+        Left (SessionUsageError _) -> True+        _ -> False
+ src/integration-tests/Specs/BySubject/UseSpec.hs view
@@ -0,0 +1,83 @@+module Specs.BySubject.UseSpec where++import Data.Text qualified as Text+import Hasql.Decoders qualified as Decoders+import Hasql.Encoders qualified as Encoders+import Hasql.Pool+import Hasql.Session qualified as Session+import Hasql.Statement qualified as Statement+import Helpers.Scripts qualified as Scripts+import Helpers.Sessions qualified as Sessions+import Test.Hspec+import Prelude++spec :: SpecWith Scripts.ScopeParams+spec = do+  it "Releases a spot in the pool when there is a query error" \scopeParams ->+    Scripts.onAutotaggedPool 1 10 1_800 1_800 scopeParams \_ pool -> do+      use pool Sessions.badQuery `shouldNotReturn` (Right ())+      use pool Sessions.selectOne `shouldReturn` (Right 1)++  it "Connection errors cause eviction of connection" \scopeParams ->+    Scripts.onAutotaggedPool 1 10 1_800 1_800 scopeParams \_ pool -> do+      _ <- use pool $ Sessions.closeConn >> Sessions.selectOne+      _ <- use pool $ Sessions.closeConn >> Sessions.selectOne+      _ <- use pool $ Sessions.closeConn >> Sessions.selectOne+      res <- use pool $ Sessions.selectOne+      shouldSatisfy res $ isRight++  it "Connection gets returned to the pool after normal use" \scopeParams ->+    Scripts.onAutotaggedPool 1 10 1_800 1_800 scopeParams \_ pool -> do+      _ <- use pool $ Sessions.selectOne+      _ <- use pool $ Sessions.selectOne+      _ <- use pool $ Sessions.selectOne+      _ <- use pool $ Sessions.selectOne+      res <- use pool $ Sessions.selectOne+      shouldSatisfy res $ isRight++  it "Connection gets returned to the pool after non-connection error" \scopeParams ->+    Scripts.onAutotaggedPool 1 10 1_800 1_800 scopeParams \_ pool -> do+      _ <- use pool $ Sessions.badQuery+      _ <- use pool $ Sessions.badQuery+      _ <- use pool $ Sessions.badQuery+      _ <- use pool $ Sessions.badQuery+      res <- use pool $ Sessions.selectOne+      shouldSatisfy res $ isRight++  it "Cached type errors cause eviction of connection" \scopeParams -> do+    typeName <- Text.replace "-" "_" <$> Scripts.generateName "cached_type_"+    Scripts.onAutotaggedPool 1 10 1_800 1_800 scopeParams \_ pool -> do+      use pool (Session.script (createTypeSql typeName)) `shouldReturn` Right ()+      use pool (roundtripEnum typeName "ok") `shouldReturn` Right "ok"+      use pool (Session.script (recreateTypeSql typeName)) `shouldReturn` Right ()+      res <- use pool (roundtripEnum typeName "ok")+      shouldSatisfy res \case+        Left (SessionUsageError _) -> True+        _ -> False+      use pool (roundtripEnum typeName "ok") `shouldReturn` Right "ok"++quoteIdentifier :: Text -> Text+quoteIdentifier identifier =+  "\"" <> Text.replace "\"" "\"\"" identifier <> "\""++createTypeSql :: Text -> Text+createTypeSql typeName =+  "create type " <> quotedTypeName <> " as enum ('sad', 'ok', 'happy')"+  where+    quotedTypeName = quoteIdentifier typeName++recreateTypeSql :: Text -> Text+recreateTypeSql typeName =+  "drop type " <> quotedTypeName <> "; create type " <> quotedTypeName <> " as enum ('sad', 'ok', 'happy')"+  where+    quotedTypeName = quoteIdentifier typeName++roundtripEnum :: Text -> Text -> Session.Session Text+roundtripEnum typeName value =+  Session.statement value statement+  where+    statement =+      Statement.preparable+        ("select $1 :: " <> quoteIdentifier typeName)+        (Encoders.param (Encoders.nonNullable (Encoders.enum Nothing typeName id)))+        (Decoders.singleRow (Decoders.column (Decoders.nonNullable (Decoders.enum Nothing typeName Just))))
+ src/library/exposed/Hasql/Pool.hs view
@@ -0,0 +1,259 @@+module Hasql.Pool+  ( -- * Pool+    Pool,+    acquire,+    use,+    release,++    -- * Errors+    UsageError (..),+  )+where++import Data.UUID.V4 qualified as Uuid+import Hasql.Connection (Connection)+import Hasql.Connection qualified as Connection+import Hasql.Connection.Settings qualified as Connection.Settings+import Hasql.Errors qualified as Errors+import Hasql.Pool.Config.Config qualified as Config+import Hasql.Pool.Observation+import Hasql.Pool.Prelude+import Hasql.Pool.SessionErrorDestructors qualified as ErrorsDestruction+import Hasql.Session qualified as Session++-- | A connection tagged with metadata.+data Entry = Entry+  { entryConnection :: Connection,+    entryCreationTimeNSec :: Word64,+    entryUseTimeNSec :: Word64,+    entryId :: UUID+  }++entryIsAged :: Word64 -> Word64 -> Entry -> Bool+entryIsAged maxLifetime now Entry {..} =+  now > entryCreationTimeNSec + maxLifetime++entryIsIdle :: Word64 -> Word64 -> Entry -> Bool+entryIsIdle maxIdletime now Entry {..} =+  now > entryUseTimeNSec + maxIdletime++-- | Pool of connections to DB.+data Pool = Pool+  { -- | Pool size.+    poolSize :: Int,+    -- | Connection settings.+    poolFetchConnectionSettings :: IO Connection.Settings.Settings,+    -- | Acquisition timeout, in microseconds.+    poolAcquisitionTimeout :: Int,+    -- | Maximal connection lifetime, in nanoseconds.+    poolMaxLifetime :: Word64,+    -- | Maximal connection idle time, in nanoseconds.+    poolMaxIdletime :: Word64,+    -- | Avail connections.+    poolConnectionQueue :: TQueue Entry,+    -- | Remaining capacity.+    -- The pool size limits the sum of poolCapacity, the length+    -- of poolConnectionQueue and the number of in-flight+    -- connections.+    poolCapacity :: TVar Int,+    -- | Whether to return a connection to the pool.+    poolReuseVar :: TVar (TVar Bool),+    -- | To stop the manager thread via garbage collection.+    poolReaperRef :: IORef (),+    -- | Action for reporting the observations.+    poolObserver :: Observation -> IO (),+    -- | Initial session to execute upon every established connection.+    poolInitSession :: Session.Session ()+  }++-- | Create a connection-pool.+--+-- No connections actually get established by this function. It is delegated+-- to 'use'.+--+-- If you want to ensure that the pool connects fine at the initialization phase, just run 'use' with an empty session (@pure ()@) and check for errors.+acquire :: Config.Config -> IO Pool+acquire config = do+  connectionQueue <- newTQueueIO+  capVar <- newTVarIO (Config.size config)+  reuseVar <- newTVarIO =<< newTVarIO True+  reaperRef <- newIORef ()++  managerTid <- forkIOWithUnmask $ \unmask -> unmask $ forever $ do+    threadDelay 1000000+    now <- getMonotonicTimeNSec+    join . atomically $ do+      entries <- flushTQueue connectionQueue+      let (agedEntries, unagedEntries) = partition (entryIsAged agingTimeoutNanos now) entries+          (idleEntries, liveEntries) = partition (entryIsIdle agingTimeoutNanos now) unagedEntries+      traverse_ (writeTQueue connectionQueue) liveEntries+      return $ do+        forM_ agedEntries $ \entry -> do+          Connection.release (entryConnection entry)+          atomically $ modifyTVar' capVar succ+          (Config.observationHandler config) (ConnectionObservation (entryId entry) (TerminatedConnectionStatus AgingConnectionTerminationReason))+        forM_ idleEntries $ \entry -> do+          Connection.release (entryConnection entry)+          atomically $ modifyTVar' capVar succ+          (Config.observationHandler config) (ConnectionObservation (entryId entry) (TerminatedConnectionStatus IdlenessConnectionTerminationReason))++  void . mkWeakIORef reaperRef $ do+    -- When the pool goes out of scope, stop the manager.+    killThread managerTid++  return $ Pool (Config.size config) (Config.connectionSettingsProvider config) acqTimeoutMicros agingTimeoutNanos maxIdletimeNanos connectionQueue capVar reuseVar reaperRef (Config.observationHandler config) (Config.initSession config)+  where+    acqTimeoutMicros =+      div (fromIntegral (diffTimeToPicoseconds (Config.acquisitionTimeout config))) 1_000_000+    agingTimeoutNanos =+      div (fromIntegral (diffTimeToPicoseconds (Config.agingTimeout config))) 1_000+    maxIdletimeNanos =+      div (fromIntegral (diffTimeToPicoseconds (Config.idlenessTimeout config))) 1_000++-- | 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 ()+release Pool {..} =+  join . atomically $ do+    prevReuse <- readTVar poolReuseVar+    writeTVar prevReuse False+    newReuse <- newTVar True+    writeTVar poolReuseVar newReuse+    entries <- flushTQueue poolConnectionQueue+    return $ forM_ entries $ \entry -> do+      Connection.release (entryConnection entry)+      atomically $ modifyTVar' poolCapacity succ+      poolObserver (ConnectionObservation (entryId entry) (TerminatedConnectionStatus ReleaseConnectionTerminationReason))++-- | Use a connection from the pool to run a session and return the connection+-- to the pool, when finished.+--+-- Session failing with a 'Session.ClientError' 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.+--+-- __Warning:__ Due to the mechanism mentioned above you should avoid intercepting this error type from within sessions.+use :: Pool -> Session.Session a -> IO (Either UsageError a)+use Pool {..} sess = do+  timeout <- do+    delay <- registerDelay poolAcquisitionTimeout+    return $ readTVar delay+  join . atomically $ do+    reuseVar <- readTVar poolReuseVar+    asum+      [ readTQueue poolConnectionQueue <&> onConn reuseVar,+        do+          capVal <- readTVar poolCapacity+          if capVal > 0+            then do+              writeTVar poolCapacity $! pred capVal+              return $ onNewConn reuseVar+            else retry,+        do+          timedOut <- timeout+          if timedOut+            then return . return . Left $ AcquisitionTimeoutUsageError+            else retry+      ]+  where+    onNewConn reuseVar = do+      settings <- poolFetchConnectionSettings+      now <- getMonotonicTimeNSec+      id <- Uuid.nextRandom+      poolObserver (ConnectionObservation id ConnectingConnectionStatus)+      Connection.acquire settings >>= \case+        Left connErr -> do+          let connErrText = case connErr of+                Errors.NetworkingConnectionError details -> Just details+                Errors.AuthenticationConnectionError details -> Just details+                Errors.CompatibilityConnectionError details -> Just details+                Errors.OtherConnectionError details -> if details == "" then Nothing else Just details+          poolObserver (ConnectionObservation id (TerminatedConnectionStatus (NetworkErrorConnectionTerminationReason connErrText)))+          atomically $ modifyTVar' poolCapacity succ+          return $ Left $ ConnectionUsageError connErr+        Right connection -> do+          Connection.use connection poolInitSession >>= \case+            Left err -> do+              Connection.release connection+              ErrorsDestruction.reset+                ( \details -> do+                    poolObserver (ConnectionObservation id (TerminatedConnectionStatus (NetworkErrorConnectionTerminationReason (Just details))))+                )+                (poolObserver (ConnectionObservation id (TerminatedConnectionStatus (InitializationErrorTerminationReason err))))+                err+              return $ Left $ SessionUsageError err+            Right () -> do+              poolObserver (ConnectionObservation id (ReadyForUseConnectionStatus EstablishedConnectionReadyForUseReason))+              onLiveConn reuseVar (Entry connection now now id)++    onConn reuseVar entry = do+      now <- getMonotonicTimeNSec+      if entryIsAged poolMaxLifetime now entry+        then do+          Connection.release (entryConnection entry)+          poolObserver (ConnectionObservation (entryId entry) (TerminatedConnectionStatus AgingConnectionTerminationReason))+          onNewConn reuseVar+        else+          if entryIsIdle poolMaxIdletime now entry+            then do+              Connection.release (entryConnection entry)+              poolObserver (ConnectionObservation (entryId entry) (TerminatedConnectionStatus IdlenessConnectionTerminationReason))+              onNewConn reuseVar+            else do+              onLiveConn reuseVar entry {entryUseTimeNSec = now}++    onLiveConn reuseVar entry = do+      poolObserver (ConnectionObservation (entryId entry) InUseConnectionStatus)+      sessRes <- try @SomeException (Connection.use (entryConnection entry) sess)++      case sessRes of+        Left exc -> do+          returnConn+          throwIO exc+        Right (Left err) ->+          if ErrorsDestruction.requiresConnectionDiscard err+            then do+              Connection.release (entryConnection entry)+              atomically $ modifyTVar' poolCapacity succ+              poolObserver+                ( ConnectionObservation+                    (entryId entry)+                    (TerminatedConnectionStatus (NetworkErrorConnectionTerminationReason (ErrorsDestruction.discardDetails err)))+                )+              return $ Left $ SessionUsageError err+            else do+              returnConn+              poolObserver (ConnectionObservation (entryId entry) (ReadyForUseConnectionStatus (SessionFailedConnectionReadyForUseReason err)))+              return $ Left $ SessionUsageError err+        Right (Right res) -> do+          returnConn+          poolObserver (ConnectionObservation (entryId entry) (ReadyForUseConnectionStatus SessionSucceededConnectionReadyForUseReason))+          return $ Right res+      where+        returnConn =+          join . atomically $ do+            reuse <- readTVar reuseVar+            if reuse+              then writeTQueue poolConnectionQueue entry $> return ()+              else return $ do+                Connection.release (entryConnection entry)+                atomically $ modifyTVar' poolCapacity succ+                poolObserver (ConnectionObservation (entryId entry) (TerminatedConnectionStatus ReleaseConnectionTerminationReason))++-- | Union over all errors that 'use' can result in.+data UsageError+  = -- | Attempt to establish a connection failed.+    ConnectionUsageError Errors.ConnectionError+  | -- | Session execution failed.+    SessionUsageError Errors.SessionError+  | -- | Timeout acquiring a connection.+    AcquisitionTimeoutUsageError+  deriving (Show, Eq)++instance Exception UsageError
+ src/library/exposed/Hasql/Pool/Config.hs view
@@ -0,0 +1,25 @@+-- | DSL for construction of configs.+module Hasql.Pool.Config+  ( Config.Config,+    settings,+    Setting.Setting,+    Setting.size,+    Setting.acquisitionTimeout,+    Setting.agingTimeout,+    Setting.idlenessTimeout,+    Setting.staticConnectionSettings,+    Setting.dynamicConnectionSettings,+    Setting.observationHandler,+    Setting.initSession,+  )+where++import Hasql.Pool.Config.Config qualified as Config+import Hasql.Pool.Config.Setting qualified as Setting+import Hasql.Pool.Prelude++-- | Compile config from a list of settings.+-- Latter settings override the preceding in cases of conflicts.+settings :: [Setting.Setting] -> Config.Config+settings =+  foldr ($) Config.defaults . fmap Setting.apply
+ src/library/exposed/Hasql/Pool/Config/Defaults.hs view
@@ -0,0 +1,47 @@+module Hasql.Pool.Config.Defaults where++import Hasql.Connection.Settings qualified as Connection.Settings+import Hasql.Pool.Observation (Observation)+import Hasql.Pool.Prelude+import Hasql.Session qualified as Session++-- |+-- 3 connections.+size :: Int+size = 3++-- |+-- 10 seconds.+acquisitionTimeout :: DiffTime+acquisitionTimeout = 10++-- |+-- 1 day.+agingTimeout :: DiffTime+agingTimeout = 60 * 60 * 24++-- |+-- 10 minutes.+idlenessTimeout :: DiffTime+idlenessTimeout = 60 * 10++-- |+-- > "postgresql://postgres:postgres@localhost:5432/postgres"+staticConnectionSettings :: Connection.Settings.Settings+staticConnectionSettings =+  "postgresql://postgres:postgres@localhost:5432/postgres"++-- |+-- > pure "postgresql://postgres:postgres@localhost:5432/postgres"+dynamicConnectionSettings :: IO Connection.Settings.Settings+dynamicConnectionSettings = pure staticConnectionSettings++-- |+-- > const (pure ())+observationHandler :: Observation -> IO ()+observationHandler = const (pure ())++-- |+-- > pure ()+initSession :: Session.Session ()+initSession = pure ()
+ src/library/exposed/Hasql/Pool/Observation.hs view
@@ -0,0 +1,64 @@+-- | Interface for processing observations of the status of the pool.+--+-- Provides a flexible mechanism for monitoring the healthiness of the pool via logs and metrics without any opinionated choices on the actual monitoring technologies.+-- Specific interpreters are encouraged to be created as extension libraries.+module Hasql.Pool.Observation where++import Hasql.Errors qualified as Errors+import Hasql.Pool.Prelude++-- | An observation of a change of the state of a pool.+data Observation+  = -- | Status of one of the pool's connections has changed.+    ConnectionObservation+      -- | Generated connection ID.+      -- For grouping the observations by one connection.+      UUID+      -- | Status that the connection has entered.+      ConnectionStatus+  deriving (Show, Eq)++-- | Status of a connection.+--+-- <<diagrams-output/connection-status-model.png>>+data ConnectionStatus+  = -- | Connection is being established.+    --+    -- This is the initial status of every connection.+    ConnectingConnectionStatus+  | -- | Connection is established and not occupied.+    ReadyForUseConnectionStatus ConnectionReadyForUseReason+  | -- | Is being used by some session.+    --+    -- After it's done the status will transition to 'ReadyForUseConnectionStatus' or 'TerminatedConnectionStatus'.+    InUseConnectionStatus+  | -- | Connection terminated.+    TerminatedConnectionStatus ConnectionTerminationReason+  deriving (Show, Eq)++data ConnectionReadyForUseReason+  = -- | Connection just got established.+    EstablishedConnectionReadyForUseReason+  | -- | Session execution ended with a failure that does not require a connection reset.+    SessionFailedConnectionReadyForUseReason Errors.SessionError+  | -- | Session execution ended with success.+    SessionSucceededConnectionReadyForUseReason+  deriving (Show, Eq)++-- | Explanation of why a connection was terminated.+data ConnectionTerminationReason+  = -- | The age timeout of the connection has passed.+    AgingConnectionTerminationReason+  | -- | The timeout of how long a connection may remain idle in the pool has passed.+    IdlenessConnectionTerminationReason+  | -- | The connection became unusable and had to be discarded.+    --+    -- This includes connectivity issues with the server as well as fatal+    -- session errors that invalidate the connection's prepared statement or+    -- type caches.+    NetworkErrorConnectionTerminationReason (Maybe Text)+  | -- | User has invoked the 'Hasql.Pool.release' procedure.+    ReleaseConnectionTerminationReason+  | -- | Initialization session failure.+    InitializationErrorTerminationReason Errors.SessionError+  deriving (Show, Eq)
+ src/library/other/Hasql/Pool/Config/Config.hs view
@@ -0,0 +1,31 @@+module Hasql.Pool.Config.Config where++import Hasql.Connection.Settings qualified as Connection.Settings+import Hasql.Pool.Config.Defaults qualified as Defaults+import Hasql.Pool.Observation (Observation)+import Hasql.Pool.Prelude+import Hasql.Session qualified as Session++-- | Configuration for Hasql connection pool.+data Config = Config+  { size :: Int,+    acquisitionTimeout :: DiffTime,+    agingTimeout :: DiffTime,+    idlenessTimeout :: DiffTime,+    connectionSettingsProvider :: IO Connection.Settings.Settings,+    observationHandler :: Observation -> IO (),+    initSession :: Session.Session ()+  }++-- | Reasonable defaults, which can be built upon.+defaults :: Config+defaults =+  Config+    { size = Defaults.size,+      acquisitionTimeout = Defaults.acquisitionTimeout,+      agingTimeout = Defaults.agingTimeout,+      idlenessTimeout = Defaults.idlenessTimeout,+      connectionSettingsProvider = Defaults.dynamicConnectionSettings,+      observationHandler = Defaults.observationHandler,+      initSession = Defaults.initSession+    }
+ src/library/other/Hasql/Pool/Config/Setting.hs view
@@ -0,0 +1,97 @@+module Hasql.Pool.Config.Setting where++import Hasql.Connection.Settings qualified as Connection.Settings+import Hasql.Pool.Config.Config (Config)+import Hasql.Pool.Config.Config qualified as Config+import Hasql.Pool.Observation (Observation)+import Hasql.Pool.Prelude+import Hasql.Session qualified as Session++apply :: Setting -> Config -> Config+apply (Setting run) = run++-- | A single setting of a config.+newtype Setting+  = Setting (Config -> Config)++-- | Pool size.+--+-- 3 by default.+size :: Int -> Setting+size x =+  Setting (\config -> config {Config.size = x})++-- | Connection acquisition timeout.+--+-- 10 seconds by default.+acquisitionTimeout :: DiffTime -> Setting+acquisitionTimeout x =+  Setting (\config -> config {Config.acquisitionTimeout = x})++-- | Maximal connection lifetime.+--+-- Determines how long is available for reuse.+-- After the timeout passes and an active session is finished the connection will be closed releasing a slot in the pool for a fresh connection to be established.+--+-- This is useful as a healthy measure for resetting the server-side caches.+--+-- 1 day by default.+agingTimeout :: DiffTime -> Setting+agingTimeout x =+  Setting (\config -> config {Config.agingTimeout = x})++-- | Maximal connection idle time.+--+-- How long to keep a connection open when it's not being used.+--+-- 10 minutes by default.+idlenessTimeout :: DiffTime -> Setting+idlenessTimeout x =+  Setting (\config -> config {Config.idlenessTimeout = x})++-- | Connection string.+--+-- By default it is:+--+-- > "postgresql://postgres:postgres@localhost:5432/postgres"+staticConnectionSettings :: Connection.Settings.Settings -> Setting+staticConnectionSettings x =+  Setting (\config -> config {Config.connectionSettingsProvider = pure x})++-- | Action providing connection settings.+--+-- Gets used each time a connection gets established by the pool.+-- This may be useful for some authorization models.+--+-- By default it is:+--+-- > pure "postgresql://postgres:postgres@localhost:5432/postgres"+dynamicConnectionSettings :: IO Connection.Settings.Settings -> Setting+dynamicConnectionSettings x =+  Setting (\config -> config {Config.connectionSettingsProvider = x})++-- | Observation handler.+--+-- Typically it's used for monitoring the state of the pool via metrics and logging.+--+-- If the provided action is not lightweight, it's recommended to use intermediate bufferring via channels like TBQueue to avoid occupying the pool management thread for too long.+-- E.g., if the action is @'atomically' . 'writeTBQueue' yourQueue@, then reading from it and processing can be done on a separate thread.+--+-- By default it is:+--+-- > const (pure ())+observationHandler :: (Observation -> IO ()) -> Setting+observationHandler x =+  Setting (\config -> config {Config.observationHandler = x})++-- | Initial session.+--+-- Gets executed on every connection upon acquisition.+-- Lets you specify the connection-wide settings.+--+-- E.g., you can set the search path for all the sessions executed by the pool by executing the following:+--+-- > initSession (Session.sql "SET search_path TO schema1, schema2, public;")+initSession :: Session.Session () -> Setting+initSession x =+  Setting (\config -> config {Config.initSession = x})
+ src/library/other/Hasql/Pool/Prelude.hs view
@@ -0,0 +1,75 @@+module Hasql.Pool.Prelude+  ( module Exports,+  )+where++import Control.Applicative as Exports hiding (WrappedArrow (..))+import Control.Arrow as Exports hiding (first, second)+import Control.Category as Exports+import Control.Concurrent as Exports+import Control.Concurrent.STM as Exports hiding (orElse)+import Control.Exception as Exports+import Control.Monad as Exports hiding (fail, forM, forM_, mapM, mapM_, msum, sequence, sequence_)+import Control.Monad.Fail as Exports+import Control.Monad.Fix as Exports hiding (fix)+import Control.Monad.IO.Class as Exports+import Control.Monad.ST as Exports+import Data.Bifunctor as Exports+import Data.Bits as Exports+import Data.Bool as Exports+import Data.ByteString as Exports (ByteString)+import Data.Char as Exports+import Data.Coerce as Exports+import Data.Complex as Exports+import Data.Data as Exports+import Data.Dynamic as Exports+import Data.Either as Exports+import Data.Fixed as Exports+import Data.Foldable as Exports hiding (toList)+import Data.Function as Exports hiding (id, (.))+import Data.Functor as Exports hiding (unzip)+import Data.Functor.Compose as Exports+import Data.IORef as Exports+import Data.Int as Exports+import Data.Ix as Exports+import Data.List as Exports hiding (all, and, any, concat, concatMap, elem, find, foldl, foldl', foldl1, foldr, foldr1, isSubsequenceOf, mapAccumL, mapAccumR, maximum, maximumBy, minimum, minimumBy, notElem, or, product, sortOn, sum, uncons)+import Data.List.NonEmpty as Exports (NonEmpty (..))+import Data.Maybe as Exports+import Data.Monoid as Exports hiding (Alt)+import Data.Ord as Exports+import Data.Proxy as Exports+import Data.Ratio as Exports+import Data.STRef as Exports+import Data.String as Exports+import Data.Text as Exports (Text)+import Data.Time as Exports+import Data.Traversable as Exports+import Data.Tuple as Exports+import Data.UUID as Exports (UUID)+import Data.Unique as Exports+import Data.Version as Exports+import Data.Void as Exports+import Data.Word as Exports+import Debug.Trace as Exports+import Foreign.ForeignPtr as Exports+import Foreign.Ptr as Exports+import Foreign.StablePtr as Exports+import Foreign.Storable as Exports+import GHC.Clock as Exports (getMonotonicTimeNSec)+import GHC.Conc as Exports hiding (orElse, threadWaitRead, threadWaitReadSTM, threadWaitWrite, threadWaitWriteSTM, withMVar)+import GHC.Exts as Exports (IsList (..), groupWith, inline, lazy, sortWith)+import GHC.Generics as Exports (Generic)+import GHC.IO.Exception as Exports+import Numeric as Exports+import System.Environment as Exports+import System.Exit as Exports+import System.IO as Exports (Handle, hClose)+import System.IO.Error as Exports+import System.IO.Unsafe as Exports+import System.Mem as Exports+import System.Mem.StableName as Exports+import System.Timeout as Exports+import Text.Printf as Exports (hPrintf, printf)+import Text.Read as Exports (Read (..), readEither, readMaybe)+import Unsafe.Coerce as Exports+import Prelude as Exports hiding (all, and, any, concat, concatMap, elem, fail, foldl, foldl1, foldr, foldr1, id, mapM, mapM_, maximum, minimum, notElem, or, product, sequence, sequence_, sum, (.))
+ src/library/other/Hasql/Pool/SessionErrorDestructors.hs view
@@ -0,0 +1,33 @@+module Hasql.Pool.SessionErrorDestructors where++import Hasql.Errors qualified as Errors+import Hasql.Pool.Prelude++reset :: (Text -> x) -> x -> Errors.SessionError -> x+reset onReset onNoReset = \case+  Errors.ConnectionSessionError details -> onReset details+  _ -> onNoReset++requiresConnectionDiscard :: Errors.SessionError -> Bool+requiresConnectionDiscard = \case+  Errors.ConnectionSessionError {} -> True+  Errors.MissingTypesSessionError {} -> True+  Errors.ScriptSessionError _ serverError -> isStaleServerError serverError+  Errors.StatementSessionError _ _ _ _ _ statementError -> statementRequiresConnectionDiscard statementError+  Errors.DriverSessionError {} -> False++discardDetails :: Errors.SessionError -> Maybe Text+discardDetails err =+  if requiresConnectionDiscard err+    then Just $ Errors.toMessage err+    else Nothing++statementRequiresConnectionDiscard :: Errors.StatementError -> Bool+statementRequiresConnectionDiscard = \case+  Errors.ServerStatementError serverError -> isStaleServerError serverError+  Errors.UnexpectedColumnTypeStatementError {} -> True+  _ -> False++isStaleServerError :: Errors.ServerError -> Bool+isStaleServerError (Errors.ServerError code _ _ _ _) =+  code == "0A000" || code == "XX000"
− test/Main.hs 
@@ -1,147 +0,0 @@-module Main where--import Control.Concurrent.Async (race)-import qualified Data.ByteString.Char8 as B8-import qualified Hasql.Connection as Connection-import qualified Hasql.Decoders as Decoders-import qualified Hasql.Encoders as Encoders-import Hasql.Pool-import qualified Hasql.Session as Session-import qualified Hasql.Statement as Statement-import qualified System.Environment-import Test.Hspec-import Prelude--main = do-  connectionSettings <- getConnectionSettings-  hspec . describe "" $ do-    it "Releases a spot in the pool when there is a query error" $ do-      pool <- acquire 1 Nothing connectionSettings-      use pool badQuerySession `shouldNotReturn` (Right ())-      use pool selectOneSession `shouldReturn` (Right 1)-    it "Simulation of connection error works" $ do-      pool <- acquire 3 Nothing connectionSettings-      res <- use pool $ closeConnSession >> selectOneSession-      shouldSatisfy res $ \case-        Left (SessionUsageError (Session.QueryError _ _ (Session.ClientError _))) -> True-        _ -> False-    it "Connection errors cause eviction of connection" $ do-      pool <- acquire 3 Nothing connectionSettings-      res <- use pool $ closeConnSession >> selectOneSession-      res <- use pool $ closeConnSession >> selectOneSession-      res <- use pool $ closeConnSession >> selectOneSession-      res <- use pool $ selectOneSession-      shouldSatisfy res $ isRight-    it "Connection gets returned to the pool after normal use" $ do-      pool <- acquire 3 Nothing connectionSettings-      res <- use pool $ selectOneSession-      res <- use pool $ selectOneSession-      res <- use pool $ selectOneSession-      res <- use pool $ selectOneSession-      res <- use pool $ selectOneSession-      shouldSatisfy res $ isRight-    it "Connection gets returned to the pool after non-connection error" $ do-      pool <- acquire 3 Nothing connectionSettings-      res <- use pool $ badQuerySession-      res <- use pool $ badQuerySession-      res <- use pool $ badQuerySession-      res <- use pool $ badQuerySession-      res <- use pool $ selectOneSession-      shouldSatisfy res $ isRight-    it "The pool remains usable after release" $ do-      pool <- acquire 1 Nothing connectionSettings-      res <- use pool $ selectOneSession-      release pool-      res <- use pool $ selectOneSession-      shouldSatisfy res $ isRight-    it "Getting and setting session variables works" $ do-      pool <- acquire 1 Nothing connectionSettings-      res <- use pool $ getSettingSession "testing.foo"-      res `shouldBe` Right Nothing-      res <- use pool $ do-        setSettingSession "testing.foo" "hello world"-        getSettingSession "testing.foo"-      res `shouldBe` Right (Just "hello world")-    it "Session variables stay set when a connection gets reused" $ do-      pool <- acquire 1 Nothing connectionSettings-      res <- use pool $ setSettingSession "testing.foo" "hello world"-      res `shouldBe` Right ()-      res2 <- use pool $ getSettingSession "testing.foo"-      res2 `shouldBe` Right (Just "hello world")-    it "Releasing the pool resets session variables" $ do-      pool <- acquire 1 Nothing connectionSettings-      res <- use pool $ setSettingSession "testing.foo" "hello world"-      res `shouldBe` Right ()-      release pool-      res <- use pool $ getSettingSession "testing.foo"-      res `shouldBe` Right Nothing-    it "Times out connection acquisition" $ do-      pool <- acquire 1 (Just 1000) connectionSettings -- 1ms timeout-      sleeping <- newEmptyMVar-      t0 <- getCurrentTime-      res <--        race-          ( use pool $-              liftIO $ do-                putMVar sleeping ()-                threadDelay 1000000 -- 1s-          )-          ( do-              takeMVar sleeping-              use pool $ selectOneSession-          )-      t1 <- getCurrentTime-      res `shouldBe` Right (Left AcquisitionTimeoutUsageError)-      diffUTCTime t1 t0 `shouldSatisfy` (< 0.5) -- 0.5s--getConnectionSettings :: IO Connection.Settings-getConnectionSettings =-  B8.unwords . catMaybes-    <$> sequence-      [ setting "host" $ defaultEnv "POSTGRES_HOST" "localhost",-        setting "port" $ defaultEnv "POSTGRES_PORT" "5432",-        setting "user" $ defaultEnv "POSTGRES_USER" "postgres",-        setting "password" $ maybeEnv "POSTGRES_PASSWORD",-        setting "dbname" $ defaultEnv "POSTGRES_DBNAME" "postgres"-      ]-  where-    maybeEnv env = fmap B8.pack <$> System.Environment.lookupEnv env-    defaultEnv env val = Just . fromMaybe val <$> maybeEnv env-    setting label getEnv = do-      val <- getEnv-      return $ (\v -> label <> "=" <> v) <$> val--selectOneSession :: Session.Session Int64-selectOneSession =-  Session.statement () statement-  where-    statement = Statement.Statement "SELECT 1" Encoders.noParams decoder True-    decoder = Decoders.singleRow (Decoders.column (Decoders.nonNullable Decoders.int8))--badQuerySession :: Session.Session ()-badQuerySession =-  Session.statement () statement-  where-    statement = Statement.Statement "zzz" Encoders.noParams Decoders.noResult True--closeConnSession :: Session.Session ()-closeConnSession = do-  conn <- ask-  liftIO $ Connection.release conn--setSettingSession :: Text -> Text -> Session.Session ()-setSettingSession name value = do-  Session.statement (name, value) statement-  where-    statement = Statement.Statement "SELECT set_config($1, $2, false)" encoder Decoders.noResult True-    encoder =-      contramap fst (Encoders.param (Encoders.nonNullable Encoders.text))-        <> contramap snd (Encoders.param (Encoders.nonNullable Encoders.text))--getSettingSession :: Text -> Session.Session (Maybe Text)-getSettingSession name = do-  Session.statement name statement-  where-    statement = Statement.Statement "SELECT current_setting($1, true)" encoder decoder True-    encoder = Encoders.param (Encoders.nonNullable Encoders.text)-    decoder = Decoders.singleRow (Decoders.column (Decoders.nullable Decoders.text))