graphql-engine/server/src-lib/Hasura/Backends/Postgres/Connection/MonadTx.hs
Auke Booij 88488362e0 chore(server): various code cleanups
- Derive a few `instance`s
- Delete some dead code (methods and types)
- Delete some `INLINE` pragmas that are unlikely to have a big effect
- Monomorphize Postgres `LISTEN` code to avoid effect juggling
- Generalize some methods in `pg-client` so that others can be simplified
- Handle errors differently for `TxET` to deduplicate code
- Use `hoist` instead of specialized combinators such as `mapActionT`

PR-URL: https://github.com/hasura/graphql-engine-mono/pull/8130
GitOrigin-RevId: bc1e908b6c0869f440a214a76744e92d40fea1e6
2023-03-14 17:47:49 +00:00

265 lines
8.7 KiB
Haskell
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

{-# LANGUAGE QuasiQuotes #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}
-- | Postgres Connection MonadTx
--
-- This module contains 'MonadTx' and related combinators.
--
-- 'MonadTx', a class which abstracts the 'QErr' in 'Q.TxE' via 'MonadError'.
--
-- The combinators are used for running, tracing, or otherwise perform database
-- related tasks. Please consult the individual documentation for more
-- information.
module Hasura.Backends.Postgres.Connection.MonadTx
( MonadTx (..),
runTxWithCtx,
runTxWithCtxAndUserInfo,
runQueryTx,
withUserInfo,
withTraceContext,
setHeadersTx,
setTraceContextInTx,
sessionInfoJsonExp,
checkDbConnection,
doesSchemaExist,
doesTableExist,
enablePgcryptoExtension,
dropHdbCatalogSchema,
ExtensionsSchema (..),
)
where
import Control.Monad.Morph (hoist)
import Control.Monad.Trans.Control (MonadBaseControl (..))
import Control.Monad.Validate
import Data.Aeson
import Data.Aeson.Extended
import Data.Time.Clock.Compat ()
import Database.PG.Query qualified as PG
import Database.PG.Query.Connection qualified as PG
import Hasura.Backends.Postgres.Execute.Types as ET
import Hasura.Backends.Postgres.SQL.DML qualified as S
import Hasura.Backends.Postgres.SQL.Types
import Hasura.Base.Error
import Hasura.Base.Instances ()
import Hasura.Prelude
import Hasura.SQL.Types
import Hasura.Session
import Hasura.Tracing qualified as Tracing
import Test.QuickCheck.Instances.Semigroup ()
import Test.QuickCheck.Instances.Time ()
class (MonadError QErr m) => MonadTx m where
liftTx :: PG.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
instance (MonadIO m) => MonadTx (PG.TxET QErr m) where
liftTx = hoist liftIO
runTxWithCtx ::
( MonadIO m,
MonadBaseControl IO m,
MonadError QErr m,
Tracing.MonadTrace m,
UserInfoM m
) =>
PGExecCtx ->
PGExecTxType ->
PGExecFrom ->
PG.TxET QErr m a ->
m a
runTxWithCtx pgExecCtx pgExecTxType pgExecFrom tx = do
userInfo <- askUserInfo
runTxWithCtxAndUserInfo userInfo pgExecCtx pgExecTxType pgExecFrom tx
runTxWithCtxAndUserInfo ::
( MonadIO m,
MonadBaseControl IO m,
MonadError QErr m,
Tracing.MonadTrace m
) =>
UserInfo ->
PGExecCtx ->
PGExecTxType ->
PGExecFrom ->
PG.TxET QErr m a ->
m a
runTxWithCtxAndUserInfo userInfo pgExecCtx pgExecTxType pgExecFrom tx = do
traceCtx <- Tracing.currentContext
liftEitherM $
runExceptT $
(_pecRunTx pgExecCtx) (PGExecCtxInfo pgExecTxType pgExecFrom) $
withTraceContext traceCtx $
withUserInfo userInfo 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,
MonadBaseControl IO m,
MonadError QErr m
) =>
PGExecCtx ->
PGExecFrom ->
PG.TxET QErr m a ->
m a
runQueryTx pgExecCtx pgExecFrom tx = do
let pgExecCtxInfo = PGExecCtxInfo NoTxRead pgExecFrom
liftEitherM $
runExceptT $
(_pecRunTx pgExecCtx) pgExecCtxInfo tx
setHeadersTx :: (MonadIO m) => SessionVariables -> PG.TxET QErr m ()
setHeadersTx session = do
PG.unitQE defaultTxErrorHandler setSess () False
where
setSess =
PG.fromText $
"SET LOCAL \"hasura.user\" = " <> toSQLTxt (sessionInfoJsonExp session)
sessionInfoJsonExp :: SessionVariables -> S.SQLExp
sessionInfoJsonExp = S.SELit . encodeToStrictText
withUserInfo :: (MonadIO m) => UserInfo -> PG.TxET QErr m a -> PG.TxET QErr m a
withUserInfo uInfo tx = setHeadersTx (_uiSession uInfo) >> tx
setTraceContextInTx :: (MonadIO m) => Maybe Tracing.TraceContext -> PG.TxET QErr m ()
setTraceContextInTx = \case
Nothing -> pure ()
Just ctx -> do
let sql = PG.fromText $ "SET LOCAL \"hasura.tracecontext\" = " <> toSQLTxt (S.SELit . encodeToStrictText . toJSON $ ctx)
PG.unitQE defaultTxErrorHandler sql () False
-- | 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) =>
Maybe (Tracing.TraceContext) ->
PG.TxET QErr m a ->
PG.TxET QErr m a
withTraceContext ctx tx = setTraceContextInTx ctx >> tx
deriving instance Tracing.MonadTrace m => Tracing.MonadTrace (PG.TxET e m)
checkDbConnection :: MonadTx m => m ()
checkDbConnection = do
PG.Discard () <- liftTx $ PG.withQE defaultTxErrorHandler [PG.sql| SELECT 1; |] () False
pure ()
doesSchemaExist :: MonadTx m => SchemaName -> m Bool
doesSchemaExist schemaName =
liftTx $
(runIdentity . PG.getRow)
<$> PG.withQE
defaultTxErrorHandler
[PG.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 . PG.getRow)
<$> PG.withQE
defaultTxErrorHandler
[PG.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 . PG.getRow)
<$> PG.withQE
defaultTxErrorHandler
[PG.sql|
SELECT EXISTS
( SELECT 1 FROM pg_catalog.pg_available_extensions
WHERE name = $1
) |]
(Identity extensionName)
False
enablePgcryptoExtension :: forall m. MonadTx m => ExtensionsSchema -> m ()
enablePgcryptoExtension (ExtensionsSchema extensionsSchema) = 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 $
PG.unitQE
needsPGCryptoError
(PG.fromText $ "CREATE EXTENSION IF NOT EXISTS pgcrypto SCHEMA " <> extensionsSchema)
()
False
where
needsPGCryptoError e@(PG.PGTxErr _ _ _ err) =
case err of
PG.PGIUnexpected _ -> requiredError e
PG.PGIStatement pgErr -> case PG.edStatusCode pgErr of
Just "42501" -> err500 PostgresError permissionsMessage
Just "P0001" -> requiredError (addHintForExtensionError pgErr)
_ -> requiredError e
where
addHintForExtensionError pgErrDetail =
e
{ PG.pgteError =
PG.PGIStatement $
PG.PGStmtErrDetail
{ PG.edExecStatus = PG.edExecStatus pgErrDetail,
PG.edStatusCode = PG.edStatusCode pgErrDetail,
PG.edMessage =
liftA2
(<>)
(PG.edMessage pgErrDetail)
(Just ". Hint: You can set \"extensions_schema\" to provide the schema to install the extensions. Refer to the documentation here: https://hasura.io/docs/latest/deployment/postgres-requirements/#pgcrypto-in-pg-search-path"),
PG.edDescription = PG.edDescription pgErrDetail,
PG.edHint = PG.edHint pgErrDetail
}
}
requiredError pgTxErr =
(err500 PostgresError requiredMessage) {qeInternal = Just $ ExtraInternal $ toJSON pgTxErr}
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 $
-- 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
PG.unitQE defaultTxErrorHandler "DROP SCHEMA IF EXISTS hdb_catalog CASCADE" () False