graphql-engine/server/src-lib/Hasura/Backends/Postgres/Connection.hs
Antoine Leblanc a805f4d185 server: misc cleanups
https://github.com/hasura/graphql-engine-mono/pull/1553

GitOrigin-RevId: b67dc40e54496ed6ad6c85755cf66745664416f7
2021-06-15 15:06:37 +00:00

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{-# OPTIONS_GHC -fno-warn-orphans #-}
{-# LANGUAGE UndecidableInstances #-}
-- A module for postgres execution related types and operations
module Hasura.Backends.Postgres.Connection
( MonadTx(..)
, LazyTxT
, LazyTx
, runLazyTx
, runQueryTx
, withUserInfo
, withTraceContext
, sessionInfoJsonExp
, RespTx
, LazyRespTx
, lazyTxToQTx
, doesSchemaExist
, doesTableExist
, enablePgcryptoExtension
, dropHdbCatalogSchema
, PostgresPoolSettings(..)
, PostgresSourceConnInfo(..)
, PostgresConnConfiguration(..)
, PGClientCerts(..)
, CertVar(..)
, CertData(..)
, SSLMode(..)
, DefaultPostgresPoolSettings(..)
, getDefaultPGPoolSettingIfNotExists
, defaultPostgresPoolSettings
, setPostgresPoolSettings
, pccConnectionInfo
, pccReadReplicas
, psciDatabaseUrl
, psciPoolSettings
, psciUsePreparedStatements
, psciIsolationLevel
, psciSslConfiguration
, module ET
) where
import Hasura.Prelude
import qualified Data.Text as T
import qualified Database.PG.Query as Q
import qualified Database.PG.Query.Connection as Q
import Control.Lens (makeLenses)
import Control.Monad.Morph (hoist)
import Control.Monad.Trans.Control (MonadBaseControl (..))
import Control.Monad.Unique
import Control.Monad.Validate
import Data.Aeson
import Data.Aeson.Casing (aesonDrop)
import Data.Aeson.Extended
import Data.Aeson.TH
import Data.Bifoldable
import Data.Bifunctor
import Data.Bitraversable
import Data.Char (toLower)
import Data.Hashable.Time ()
import Data.Semigroup (Max (..))
import Data.Text (unpack)
import Data.Time
import Network.HTTP.Client.Extended (HasHttpManagerM (..))
import Test.QuickCheck.Instances.Semigroup ()
import Test.QuickCheck.Instances.Time ()
import qualified Hasura.Backends.Postgres.SQL.DML as S
import qualified Hasura.Tracing as Tracing
import Hasura.Backends.Postgres.Execute.Types as ET
import Hasura.Backends.Postgres.SQL.Types
import Hasura.Base.Error
import Hasura.Base.Instances ()
import Hasura.EncJSON
import Hasura.Incremental (Cacheable (..))
import Hasura.RQL.Types.Common (UrlConf (..))
import Hasura.SQL.Types
import Hasura.Server.Utils (parseConnLifeTime, readIsoLevel)
import Hasura.Session
class (MonadError QErr m) => MonadTx m where
liftTx :: Q.TxE QErr a -> m a
instance (MonadTx m) => MonadTx (StateT s m) where
liftTx = lift . liftTx
instance (MonadTx m) => MonadTx (ReaderT s m) where
liftTx = lift . liftTx
instance (Monoid w, MonadTx m) => MonadTx (WriterT w m) where
liftTx = lift . liftTx
instance (MonadTx m) => MonadTx (ValidateT e m) where
liftTx = lift . liftTx
instance (MonadTx m) => MonadTx (Tracing.TraceT m) where
liftTx = lift . liftTx
-- | Like 'Q.TxE', but defers acquiring a Postgres connection until the first
-- execution of 'liftTx'. If no call to 'liftTx' is ever reached (i.e. a
-- successful result is returned or an error is raised before ever executing a
-- query), no connection is ever acquired.
--
-- This is useful for certain code paths that only conditionally need database
-- access. For example, although most queries will eventually hit Postgres,
-- introspection queries or queries that exclusively use remote schemas never
-- will; using 'LazyTxT e m' keeps those branches from unnecessarily allocating a
-- connection.
data LazyTxT e m a
= LTErr !e
| LTNoTx !a
| LTTx !(Q.TxET e m a)
deriving (Show, Functor)
-- orphan:
instance Show (Q.TxET e m a) where
show = const "(error \"TxE\")"
lazyTxToQTx :: (Monad m) => LazyTxT e m a -> Q.TxET e m a
lazyTxToQTx = \case
LTErr e -> throwError e
LTNoTx r -> return r
LTTx tx -> tx
runLazyTx
:: ( MonadIO m
, MonadBaseControl IO m
)
=> PGExecCtx
-> Q.TxAccess
-> LazyTxT QErr m a -> ExceptT QErr m a
runLazyTx pgExecCtx txAccess = \case
LTErr e -> throwError e
LTNoTx a -> return a
LTTx tx ->
case txAccess of
Q.ReadOnly -> _pecRunReadOnly pgExecCtx tx
Q.ReadWrite -> _pecRunReadWrite pgExecCtx tx
-- | This runs the given set of statements (Tx) without wrapping them in BEGIN
-- and COMMIT. This should only be used for running a single statement query!
runQueryTx
:: (MonadIO m, MonadError QErr m) => PGExecCtx -> LazyTx QErr a -> m a
runQueryTx pgExecCtx = \case
LTErr e -> throwError e
LTNoTx a -> return a
LTTx tx -> liftEither =<< liftIO (runExceptT $ _pecRunReadNoTx pgExecCtx tx)
type RespTx = Q.TxE QErr EncJSON
type LazyTx e a = LazyTxT e IO a
type LazyRespTx = LazyTx QErr EncJSON
setHeadersTx :: (MonadIO m) => SessionVariables -> Q.TxET QErr m ()
setHeadersTx session = do
Q.unitQE defaultTxErrorHandler setSess () False
where
setSess = Q.fromText $
"SET LOCAL \"hasura.user\" = " <> toSQLTxt (sessionInfoJsonExp session)
sessionInfoJsonExp :: SessionVariables -> S.SQLExp
sessionInfoJsonExp = S.SELit . encodeToStrictText
withUserInfo :: (MonadIO m) => UserInfo -> LazyTxT QErr m a -> LazyTxT QErr m a
withUserInfo uInfo = \case
LTErr e -> LTErr e
LTNoTx a -> LTNoTx a
LTTx tx ->
let vars = _uiSession uInfo
in LTTx $ setHeadersTx vars >> tx
-- | Inject the trace context as a transaction-local variable,
-- so that it can be picked up by any triggers (including event triggers).
withTraceContext
:: (MonadIO m)
=> Tracing.TraceContext
-> LazyTxT QErr m a
-> LazyTxT QErr m a
withTraceContext ctx = \case
LTErr e -> LTErr e
LTNoTx a -> LTNoTx a
LTTx tx ->
let sql = Q.fromText $
"SET LOCAL \"hasura.tracecontext\" = " <>
toSQLTxt (S.SELit . encodeToStrictText . Tracing.injectEventContext $ ctx)
setTraceContext =
Q.unitQE defaultTxErrorHandler sql () False
in LTTx $ setTraceContext >> tx
instance (Monad m) => Applicative (LazyTxT e m) where
pure = LTNoTx
LTErr e <*> _ = LTErr e
LTNoTx f <*> r = fmap f r
LTTx _ <*> LTErr e = LTErr e
LTTx txf <*> LTNoTx a = LTTx $ txf <*> pure a
LTTx txf <*> LTTx tx = LTTx $ txf <*> tx
instance (Monad m) => Monad (LazyTxT e m) where
LTErr e >>= _ = LTErr e
LTNoTx a >>= f = f a
LTTx txa >>= f =
LTTx $ txa >>= lazyTxToQTx . f
instance (Monad m) => MonadError e (LazyTxT e m) where
throwError = LTErr
LTErr e `catchError` f = f e
LTNoTx a `catchError` _ = LTNoTx a
LTTx txe `catchError` f =
LTTx $ txe `catchError` (lazyTxToQTx . f)
instance MonadTrans (LazyTxT e) where
lift = LTTx . lift
instance (Tracing.MonadTrace m) => Tracing.MonadTrace (LazyTxT e m) where
trace t = \case
LTTx (Q.TxET tx) -> LTTx $ Q.TxET $ Tracing.trace t tx
v -> v
currentContext = lift Tracing.currentContext
currentReporter = lift Tracing.currentReporter
attachMetadata = lift . Tracing.attachMetadata
instance UserInfoM m => UserInfoM (LazyTxT e m) where
askUserInfo = lift askUserInfo
instance HasHttpManagerM m => HasHttpManagerM (LazyTxT e m) where
askHttpManager = lift askHttpManager
instance (MonadIO m) => MonadTx (LazyTxT QErr m) where
liftTx = LTTx . (hoist liftIO)
instance (MonadIO m) => MonadTx (Q.TxET QErr m) where
liftTx = hoist liftIO
instance (MonadIO m) => MonadIO (LazyTxT e m) where
liftIO = LTTx . liftIO
instance (MonadIO m) => MonadBase IO (LazyTxT e m) where
liftBase = liftIO
instance (MonadIO m, MonadBaseControl IO m) => MonadBaseControl IO (LazyTxT e m) where
type StM (LazyTxT e m) a = StM (Q.TxET e m) a
liftBaseWith f = LTTx $ liftBaseWith \run -> f (run . lazyTxToQTx)
restoreM = LTTx . restoreM
instance (MonadIO m) => MonadUnique (LazyTxT e m) where
newUnique = liftIO newUnique
doesSchemaExist :: MonadTx m => SchemaName -> m Bool
doesSchemaExist schemaName =
liftTx $ (runIdentity . Q.getRow) <$> Q.withQE defaultTxErrorHandler [Q.sql|
SELECT EXISTS
( SELECT 1 FROM information_schema.schemata
WHERE schema_name = $1
) |] (Identity schemaName) False
doesTableExist :: MonadTx m => SchemaName -> TableName -> m Bool
doesTableExist schemaName tableName =
liftTx $ (runIdentity . Q.getRow) <$> Q.withQE defaultTxErrorHandler [Q.sql|
SELECT EXISTS
( SELECT 1 FROM pg_tables
WHERE schemaname = $1 AND tablename = $2
) |] (schemaName, tableName) False
isExtensionAvailable :: MonadTx m => Text -> m Bool
isExtensionAvailable extensionName =
liftTx $ (runIdentity . Q.getRow) <$> Q.withQE defaultTxErrorHandler [Q.sql|
SELECT EXISTS
( SELECT 1 FROM pg_catalog.pg_available_extensions
WHERE name = $1
) |] (Identity extensionName) False
enablePgcryptoExtension :: forall m. MonadTx m => m ()
enablePgcryptoExtension = do
pgcryptoAvailable <- isExtensionAvailable "pgcrypto"
if pgcryptoAvailable then createPgcryptoExtension
else throw400 Unexpected $
"pgcrypto extension is required, but could not find the extension in the "
<> "PostgreSQL server. Please make sure this extension is available."
where
createPgcryptoExtension :: m ()
createPgcryptoExtension =
liftTx $ Q.unitQE needsPGCryptoError
"CREATE EXTENSION IF NOT EXISTS pgcrypto SCHEMA public" () False
where
needsPGCryptoError e@(Q.PGTxErr _ _ _ err) =
case err of
Q.PGIUnexpected _ -> requiredError
Q.PGIStatement pgErr -> case Q.edStatusCode pgErr of
Just "42501" -> err500 PostgresError permissionsMessage
_ -> requiredError
where
requiredError =
(err500 PostgresError requiredMessage) { qeInternal = Just $ toJSON e }
requiredMessage =
"pgcrypto extension is required, but it could not be created;"
<> " encountered unknown postgres error"
permissionsMessage =
"pgcrypto extension is required, but the current user doesnt have permission to"
<> " create it. Please grant superuser permission, or setup the initial schema via"
<> " https://hasura.io/docs/latest/graphql/core/deployment/postgres-permissions.html"
dropHdbCatalogSchema :: (MonadTx m) => m ()
dropHdbCatalogSchema = liftTx $ Q.catchE defaultTxErrorHandler $
-- This is where
-- 1. Metadata storage:- Metadata and its stateful information stored
-- 2. Postgres source:- Table event trigger related stuff & insert permission check function stored
Q.unitQ "DROP SCHEMA IF EXISTS hdb_catalog CASCADE" () False
data PostgresPoolSettings
= PostgresPoolSettings
{ _ppsMaxConnections :: !(Maybe Int)
, _ppsIdleTimeout :: !(Maybe Int)
, _ppsRetries :: !(Maybe Int)
, _ppsPoolTimeout :: !(Maybe NominalDiffTime)
, _ppsConnectionLifetime :: !(Maybe NominalDiffTime)
} deriving (Show, Eq, Generic)
instance Cacheable PostgresPoolSettings
instance Hashable PostgresPoolSettings
instance NFData PostgresPoolSettings
$(deriveToJSON hasuraJSON{omitNothingFields = True} ''PostgresPoolSettings)
instance FromJSON PostgresPoolSettings where
parseJSON = withObject "PostgresPoolSettings" $ \o ->
PostgresPoolSettings
<$> o .:? "max_connections"
<*> o .:? "idle_timeout"
<*> o .:? "retries"
<*> o .:? "pool_timeout"
<*> ((o .:? "connection_lifetime") <&> parseConnLifeTime)
instance Arbitrary PostgresPoolSettings where
arbitrary = genericArbitrary
data DefaultPostgresPoolSettings =
DefaultPostgresPoolSettings
{ _dppsMaxConnections :: !Int
, _dppsIdleTimeout :: !Int
, _dppsRetries :: !Int
, _dppsConnectionLifetime :: !(Maybe NominalDiffTime)
} deriving (Show, Eq)
defaultPostgresPoolSettings :: DefaultPostgresPoolSettings
defaultPostgresPoolSettings = DefaultPostgresPoolSettings 50 180 1 (Just 600)
-- Use this when you want to set only few of the PG Pool settings.
-- The values which are not set will use the default values.
setPostgresPoolSettings :: PostgresPoolSettings
setPostgresPoolSettings =
PostgresPoolSettings
{ _ppsMaxConnections = (Just $ _dppsMaxConnections defaultPostgresPoolSettings)
, _ppsIdleTimeout = (Just $ _dppsIdleTimeout defaultPostgresPoolSettings)
, _ppsRetries = (Just $ _dppsRetries defaultPostgresPoolSettings)
, _ppsPoolTimeout = Nothing -- @Nothing@ is the default value of the pool timeout
, _ppsConnectionLifetime = _dppsConnectionLifetime defaultPostgresPoolSettings
}
-- PG Pool Settings are not given by the user, set defaults
getDefaultPGPoolSettingIfNotExists :: Maybe PostgresPoolSettings -> DefaultPostgresPoolSettings -> (Int, Int, Int)
getDefaultPGPoolSettingIfNotExists connSettings defaultPgPoolSettings =
case connSettings of
-- Atleast one of the postgres pool settings is set, then set default values to other settings
Just connSettings' ->
(maxConnections connSettings', idleTimeout connSettings', retries connSettings')
-- No PG Pool settings provided by user, set default values for all
Nothing -> (defMaxConnections, defIdleTimeout, defRetries)
where
defMaxConnections = _dppsMaxConnections defaultPgPoolSettings
defIdleTimeout = _dppsIdleTimeout defaultPgPoolSettings
defRetries = _dppsRetries defaultPgPoolSettings
maxConnections = fromMaybe defMaxConnections . _ppsMaxConnections
idleTimeout = fromMaybe defIdleTimeout . _ppsIdleTimeout
retries = fromMaybe defRetries . _ppsRetries
data SSLMode =
Disable
| Allow
| Prefer
| Require
| VerifyCA
| VerifyFull
deriving (Eq, Ord, Generic, Enum, Bounded)
instance Cacheable SSLMode
instance Hashable SSLMode
instance NFData SSLMode
instance Arbitrary SSLMode where
arbitrary = genericArbitrary
instance Show SSLMode where
show = \case
Disable -> "disable"
Allow -> "allow"
Prefer -> "prefer"
Require -> "require"
VerifyCA -> "verify-ca"
VerifyFull -> "verify-full"
deriving via (Max SSLMode) instance Semigroup SSLMode
instance FromJSON SSLMode where
parseJSON = withText "SSLMode" $ \case
"disable" -> pure Disable
"allow" -> pure Allow
"prefer" -> pure Prefer
"require" -> pure Require
"verify-ca" -> pure VerifyCA
"verify-full" -> pure VerifyFull
err -> fail $ "Invalid SSL Mode " <> unpack err
data CertVar
= CertVar String
| CertLiteral String
deriving (Show, Eq, Generic)
instance Cacheable CertVar
instance Hashable CertVar
instance NFData CertVar
instance ToJSON CertVar where
toJSON (CertVar var) = (object ["from_env" .= var])
toJSON (CertLiteral var) = String (T.pack var)
instance FromJSON CertVar where
parseJSON (String s) = pure (CertLiteral (T.unpack s))
parseJSON x = withObject "CertVar" (\o -> CertVar <$> o .: "from_env") x
instance Arbitrary CertVar where
arbitrary = genericArbitrary
newtype CertData = CertData { unCert :: Text }
deriving (Show, Eq, Generic)
instance ToJSON CertData where
toJSON = String . unCert
instance Arbitrary CertData where
arbitrary = genericArbitrary
data PGClientCerts p a = PGClientCerts
{ pgcSslCert :: a
, pgcSslKey :: a
, pgcSslRootCert :: a
, pgcSslMode :: SSLMode
, pgcSslPassword :: Maybe p
} deriving (Show, Eq, Generic, Functor, Foldable, Traversable)
$(deriveFromJSON (aesonDrop 3 (fmap toLower)) ''PGClientCerts)
$(deriveToJSON (aesonDrop 3 (fmap toLower)) ''PGClientCerts)
instance Bifunctor PGClientCerts where
bimap f g pgCerts = g <$> pgCerts { pgcSslPassword = f <$> (pgcSslPassword pgCerts)}
instance Bifoldable PGClientCerts where
bifoldMap f g PGClientCerts{..} =
fold $ fmap g [pgcSslCert, pgcSslKey, pgcSslRootCert] <> maybe [] (pure . f) pgcSslPassword
instance Bitraversable PGClientCerts where
bitraverse f g PGClientCerts{..} =
PGClientCerts <$> g pgcSslCert <*> g pgcSslKey <*> g pgcSslRootCert <*> pure pgcSslMode <*> traverse f pgcSslPassword
instance (Cacheable p, Cacheable a) => Cacheable (PGClientCerts p a)
instance (Hashable p, Hashable a) => Hashable (PGClientCerts p a)
instance (NFData p, NFData a) => NFData (PGClientCerts p a)
instance ToJSON SSLMode where
toJSON = String . tshow
instance (Arbitrary p, Arbitrary a) => Arbitrary (PGClientCerts p a) where
arbitrary = genericArbitrary
deriving instance Generic Q.TxIsolation
instance Cacheable Q.TxIsolation
instance NFData Q.TxIsolation
instance Hashable Q.TxIsolation
instance FromJSON Q.TxIsolation where
parseJSON = withText "Q.TxIsolation" $ \t ->
onLeft (readIsoLevel $ T.unpack t) fail
instance ToJSON Q.TxIsolation where
toJSON Q.ReadCommitted = "read-committed"
toJSON Q.RepeatableRead = "repeatable-read"
toJSON Q.Serializable = "serializable"
instance Arbitrary Q.TxIsolation where
arbitrary = genericArbitrary
data PostgresSourceConnInfo
= PostgresSourceConnInfo
{ _psciDatabaseUrl :: !UrlConf
, _psciPoolSettings :: !(Maybe PostgresPoolSettings)
, _psciUsePreparedStatements :: !Bool
, _psciIsolationLevel :: !Q.TxIsolation
, _psciSslConfiguration :: !(Maybe (PGClientCerts CertVar CertVar))
} deriving (Show, Eq, Generic)
instance Cacheable PostgresSourceConnInfo
instance Hashable PostgresSourceConnInfo
instance NFData PostgresSourceConnInfo
$(deriveToJSON hasuraJSON{omitNothingFields = True} ''PostgresSourceConnInfo)
$(makeLenses ''PostgresSourceConnInfo)
instance FromJSON PostgresSourceConnInfo where
parseJSON = withObject "PostgresSourceConnInfo" $ \o ->
PostgresSourceConnInfo
<$> o .: "database_url"
<*> o .:? "pool_settings"
<*> o .:? "use_prepared_statements" .!= False -- By default preparing statements is OFF for postgres source
<*> o .:? "isolation_level" .!= Q.ReadCommitted
<*> o .:? "ssl_configuration"
instance Arbitrary PostgresSourceConnInfo where
arbitrary = genericArbitrary
data PostgresConnConfiguration
= PostgresConnConfiguration
{ _pccConnectionInfo :: !PostgresSourceConnInfo
, _pccReadReplicas :: !(Maybe (NonEmpty PostgresSourceConnInfo))
} deriving (Show, Eq, Generic)
instance Cacheable PostgresConnConfiguration
instance Hashable PostgresConnConfiguration
instance NFData PostgresConnConfiguration
$(deriveJSON hasuraJSON{omitNothingFields = True} ''PostgresConnConfiguration)
$(makeLenses ''PostgresConnConfiguration)
instance Arbitrary PostgresConnConfiguration where
arbitrary = genericArbitrary