graphql-engine/server/src-lib/Hasura/Backends/Postgres/Execute/Mutation.hs
Antoine Leblanc ba70ca427a server: switch to a sub-backend approach
GitOrigin-RevId: 660126d5f65620fb58a3ffcbed564e9e35f59938
2021-04-21 21:45:32 +00:00

297 lines
10 KiB
Haskell

module Hasura.Backends.Postgres.Execute.Mutation
( MutationRemoteJoinCtx
, MutateResp(..)
--
, execDeleteQuery
, execInsertQuery
, execUpdateQuery
--
, executeMutationOutputQuery
, mutateAndFetchCols
) where
import Hasura.Prelude
import qualified Data.Environment as Env
import qualified Data.Sequence as DS
import qualified Database.PG.Query as Q
import qualified Network.HTTP.Client as HTTP
import qualified Network.HTTP.Types as N
import Data.Aeson
import qualified Hasura.Backends.Postgres.SQL.DML as S
import qualified Hasura.Tracing as Tracing
import Hasura.Backends.Postgres.Connection
import Hasura.Backends.Postgres.Execute.RemoteJoin
import Hasura.Backends.Postgres.SQL.Types
import Hasura.Backends.Postgres.SQL.Value
import Hasura.Backends.Postgres.Translate.Delete
import Hasura.Backends.Postgres.Translate.Insert
import Hasura.Backends.Postgres.Translate.Mutation
import Hasura.Backends.Postgres.Translate.Returning
import Hasura.Backends.Postgres.Translate.Select
import Hasura.Backends.Postgres.Translate.Update
import Hasura.EncJSON
import Hasura.RQL.DML.Internal
import Hasura.RQL.IR.Delete
import Hasura.RQL.IR.Insert
import Hasura.RQL.IR.Returning
import Hasura.RQL.IR.Select
import Hasura.RQL.IR.Update
import Hasura.RQL.Instances ()
import Hasura.RQL.Types
import Hasura.SQL.Types
import Hasura.Server.Version (HasVersion)
import Hasura.Session
data MutateResp (b :: BackendType) a
= MutateResp
{ _mrAffectedRows :: !Int
, _mrReturningColumns :: ![ColumnValues b a]
} deriving (Generic)
deriving instance (Backend b, Show a) => Show (MutateResp b a)
deriving instance (Backend b, Eq a) => Eq (MutateResp b a)
instance (Backend b, ToJSON a) => ToJSON (MutateResp b a) where
toJSON = genericToJSON hasuraJSON
instance (Backend b, FromJSON a) => FromJSON (MutateResp b a) where
parseJSON = genericParseJSON hasuraJSON
type MutationRemoteJoinCtx = (HTTP.Manager, [N.Header], UserInfo)
data Mutation (b :: BackendType)
= Mutation
{ _mTable :: !QualifiedTable
, _mQuery :: !(MutationCTE, DS.Seq Q.PrepArg)
, _mOutput :: !(MutationOutput b)
, _mCols :: ![ColumnInfo b]
, _mRemoteJoins :: !(Maybe (RemoteJoins b, MutationRemoteJoinCtx))
, _mStrfyNum :: !Bool
}
mkMutation
:: Backend ('Postgres pgKind)
=> Maybe MutationRemoteJoinCtx
-> QualifiedTable
-> (MutationCTE, DS.Seq Q.PrepArg)
-> MutationOutput ('Postgres pgKind)
-> [ColumnInfo ('Postgres pgKind)]
-> Bool
-> Mutation ('Postgres pgKind)
mkMutation ctx table query output' allCols strfyNum =
let (output, remoteJoins) = getRemoteJoinsMutationOutput output'
remoteJoinsCtx = (,) <$> remoteJoins <*> ctx
in Mutation table query output allCols remoteJoinsCtx strfyNum
runMutation
::
( HasVersion
, MonadTx m
, MonadIO m
, Tracing.MonadTrace m
, Backend ('Postgres pgKind)
)
=> Env.Environment
-> Mutation ('Postgres pgKind)
-> m EncJSON
runMutation env mut =
bool (mutateAndReturn env mut) (mutateAndSel env mut) $
hasNestedFld $ _mOutput mut
mutateAndReturn
::
( HasVersion
, MonadTx m
, MonadIO m
, Tracing.MonadTrace m
, Backend ('Postgres pgKind)
)
=> Env.Environment
-> Mutation ('Postgres pgKind)
-> m EncJSON
mutateAndReturn env (Mutation qt (cte, p) mutationOutput allCols remoteJoins strfyNum) =
executeMutationOutputQuery env qt allCols Nothing cte mutationOutput strfyNum (toList p) remoteJoins
execUpdateQuery
::
( HasVersion
, MonadTx m
, MonadIO m
, Tracing.MonadTrace m
, Backend ('Postgres pgKind)
)
=> Env.Environment
-> Bool
-> Maybe MutationRemoteJoinCtx
-> (AnnUpd ('Postgres pgKind), DS.Seq Q.PrepArg)
-> m EncJSON
execUpdateQuery env strfyNum remoteJoinCtx (u, p) =
runMutation env $ mkMutation remoteJoinCtx (uqp1Table u) (MCCheckConstraint updateCTE, p)
(uqp1Output u) (uqp1AllCols u) strfyNum
where
updateCTE = mkUpdateCTE u
execDeleteQuery
::
( HasVersion
, MonadTx m
, MonadIO m
, Tracing.MonadTrace m
, Backend ('Postgres pgKind)
)
=> Env.Environment
-> Bool
-> Maybe MutationRemoteJoinCtx
-> (AnnDel ('Postgres pgKind), DS.Seq Q.PrepArg)
-> m EncJSON
execDeleteQuery env strfyNum remoteJoinCtx (u, p) =
runMutation env $ mkMutation remoteJoinCtx (dqp1Table u) (MCDelete delete, p)
(dqp1Output u) (dqp1AllCols u) strfyNum
where
delete = mkDelete u
execInsertQuery
:: ( HasVersion
, MonadTx m
, MonadIO m
, Tracing.MonadTrace m
, Backend ('Postgres pgKind)
)
=> Env.Environment
-> Bool
-> Maybe MutationRemoteJoinCtx
-> (InsertQueryP1 ('Postgres pgKind), DS.Seq Q.PrepArg)
-> m EncJSON
execInsertQuery env strfyNum remoteJoinCtx (u, p) =
runMutation env
$ mkMutation remoteJoinCtx (iqp1Table u) (MCCheckConstraint insertCTE, p)
(iqp1Output u) (iqp1AllCols u) strfyNum
where
insertCTE = mkInsertCTE u
{- Note: [Prepared statements in Mutations]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The SQL statements we generate for mutations seem to include the actual values
in the statements in some cases which pretty much makes them unfit for reuse
(Handling relationships in the returning clause is the source of this
complexity). Further, `PGConn` has an internal cache which maps a statement to
a 'prepared statement id' on Postgres. As we prepare more and more single-use
SQL statements we end up leaking memory both on graphql-engine and Postgres
till the connection is closed. So a simpler but very crude fix is to not use
prepared statements for mutations. The performance of insert mutations
shouldn't be affected but updates and delete mutations with complex boolean
conditions **might** see some degradation.
-}
mutateAndSel
:: forall pgKind m
. ( HasVersion
, MonadTx m
, MonadIO m
, Tracing.MonadTrace m
, Backend ('Postgres pgKind)
)
=> Env.Environment
-> Mutation ('Postgres pgKind)
-> m EncJSON
mutateAndSel env (Mutation qt q mutationOutput allCols remoteJoins strfyNum) = do
-- Perform mutation and fetch unique columns
MutateResp _ columnVals <- liftTx $ mutateAndFetchCols qt allCols q strfyNum
select <- mkSelectExpFromColumnValues qt allCols columnVals
-- Perform select query and fetch returning fields
executeMutationOutputQuery env qt allCols Nothing
(MCSelectValues select) mutationOutput strfyNum [] remoteJoins
withCheckPermission :: (MonadError QErr m) => m (a, Bool) -> m a
withCheckPermission sqlTx = do
(rawResponse, checkConstraint) <- sqlTx
unless checkConstraint $ throw400 PermissionError $
"check constraint of an insert/update permission has failed"
pure rawResponse
executeMutationOutputQuery
:: forall pgKind m
. ( HasVersion
, MonadTx m
, MonadIO m
, Tracing.MonadTrace m
, Backend ('Postgres pgKind)
)
=> Env.Environment
-> QualifiedTable
-> [ColumnInfo ('Postgres pgKind)]
-> Maybe Int
-> MutationCTE
-> MutationOutput ('Postgres pgKind)
-> Bool
-> [Q.PrepArg] -- ^ Prepared params
-> Maybe (RemoteJoins ('Postgres pgKind), MutationRemoteJoinCtx) -- ^ Remote joins context
-> m EncJSON
executeMutationOutputQuery env qt allCols preCalAffRows cte mutOutput strfyNum prepArgs maybeRJ = do
let queryTx :: Q.FromRes a => m a
queryTx = do
let selectWith = mkMutationOutputExp qt allCols preCalAffRows cte mutOutput strfyNum
query = Q.fromBuilder $ toSQL selectWith
-- See Note [Prepared statements in Mutations]
liftTx (Q.rawQE dmlTxErrorHandler query prepArgs False)
rawResponse <-
if checkPermissionRequired cte
then withCheckPermission $ Q.getRow <$> queryTx
else (runIdentity . Q.getRow) <$> queryTx
case maybeRJ of
Nothing -> pure $ encJFromLBS rawResponse
Just (remoteJoins, (httpManager, reqHeaders, userInfo)) ->
processRemoteJoins env httpManager reqHeaders userInfo rawResponse remoteJoins
mutateAndFetchCols
:: forall pgKind
. Backend ('Postgres pgKind)
=> QualifiedTable
-> [ColumnInfo ('Postgres pgKind)]
-> (MutationCTE, DS.Seq Q.PrepArg)
-> Bool
-> Q.TxE QErr (MutateResp ('Postgres pgKind) TxtEncodedVal)
mutateAndFetchCols qt cols (cte, p) strfyNum = do
let mutationTx :: Q.FromRes a => Q.TxE QErr a
mutationTx =
-- See Note [Prepared statements in Mutations]
Q.rawQE dmlTxErrorHandler sqlText (toList p) False
if checkPermissionRequired cte
then withCheckPermission $ (first Q.getAltJ . Q.getRow) <$> mutationTx
else (Q.getAltJ . runIdentity . Q.getRow) <$> mutationTx
where
aliasIdentifier = Identifier $ qualifiedObjectToText qt <> "__mutation_result"
tabFrom = FromIdentifier aliasIdentifier
tabPerm = TablePerm annBoolExpTrue Nothing
selFlds = flip map cols $
\ci -> (fromCol @('Postgres pgKind) $ pgiColumn ci, mkAnnColumnFieldAsText ci)
sqlText = Q.fromBuilder $ toSQL selectWith
selectWith = S.SelectWith [(S.Alias aliasIdentifier, getMutationCTE cte)] select
select = S.mkSelect { S.selExtr = S.Extractor extrExp Nothing
: bool [] [S.Extractor checkErrExp Nothing] (checkPermissionRequired cte)
}
checkErrExp = mkCheckErrorExp aliasIdentifier
extrExp = S.applyJsonBuildObj
[ S.SELit "affected_rows", affRowsSel
, S.SELit "returning_columns", colSel
]
affRowsSel = S.SESelect $
S.mkSelect
{ S.selExtr = [S.Extractor S.countStar Nothing]
, S.selFrom = Just $ S.FromExp [S.FIIdentifier aliasIdentifier]
}
colSel = S.SESelect $ mkSQLSelect JASMultipleRows $
AnnSelectG selFlds tabFrom tabPerm noSelectArgs strfyNum