mirror of
https://github.com/hasura/graphql-engine.git
synced 2024-12-18 04:51:35 +03:00
394 lines
18 KiB
Haskell
394 lines
18 KiB
Haskell
{-# LANGUAGE UndecidableInstances #-}
|
||
|
||
-- | Construction of multiplexed live query plans; see "Hasura.GraphQL.Execute.LiveQuery" for
|
||
-- details.
|
||
module Hasura.GraphQL.Execute.LiveQuery.Plan
|
||
( MultiplexedQuery
|
||
, mkMultiplexedQuery
|
||
, unMultiplexedQuery
|
||
, resolveMultiplexedValue
|
||
|
||
, CohortId
|
||
, newCohortId
|
||
, CohortVariables
|
||
, executeMultiplexedQuery
|
||
|
||
, LiveQueryPlan(..)
|
||
, ParameterizedLiveQueryPlan(..)
|
||
, ReusableLiveQueryPlan
|
||
, ValidatedQueryVariables
|
||
, buildLiveQueryPlan
|
||
-- , reuseLiveQueryPlan
|
||
|
||
, LiveQueryPlanExplanation
|
||
, explainLiveQueryPlan
|
||
) where
|
||
|
||
import Hasura.Prelude
|
||
import Hasura.Session
|
||
|
||
import qualified Data.Aeson.Casing as J
|
||
import qualified Data.Aeson.Extended as J
|
||
import qualified Data.Aeson.TH as J
|
||
import qualified Data.ByteString as B
|
||
import qualified Data.HashMap.Strict as Map
|
||
import qualified Data.HashMap.Strict.InsOrd as OMap
|
||
import qualified Data.Sequence as Seq
|
||
import qualified Data.Text as T
|
||
import qualified Data.UUID.V4 as UUID
|
||
import qualified Database.PG.Query as Q
|
||
import qualified Language.GraphQL.Draft.Syntax as G
|
||
|
||
-- remove these when array encoding is merged
|
||
import qualified Database.PG.Query.PTI as PTI
|
||
import qualified PostgreSQL.Binary.Encoding as PE
|
||
|
||
import Control.Lens
|
||
import Data.UUID (UUID)
|
||
|
||
import qualified Hasura.GraphQL.Parser.Schema as PS
|
||
-- import qualified Hasura.GraphQL.Transport.HTTP.Protocol as GH
|
||
import qualified Hasura.RQL.DML.RemoteJoin as RR
|
||
import qualified Hasura.RQL.DML.Select as DS
|
||
import qualified Hasura.SQL.DML as S
|
||
|
||
import Hasura.Db
|
||
import Hasura.GraphQL.Context
|
||
import Hasura.GraphQL.Execute.Action
|
||
import Hasura.GraphQL.Execute.Query
|
||
import Hasura.GraphQL.Parser.Column
|
||
import Hasura.RQL.Types
|
||
import Hasura.SQL.Error
|
||
import Hasura.SQL.Types
|
||
import Hasura.SQL.Value
|
||
|
||
-- -------------------------------------------------------------------------------------------------
|
||
-- Multiplexed queries
|
||
|
||
newtype MultiplexedQuery = MultiplexedQuery { unMultiplexedQuery :: Q.Query }
|
||
deriving (Show, Eq, Hashable, J.ToJSON)
|
||
|
||
toSQLFromItem :: S.Alias -> SubscriptionRootFieldResolved -> S.FromItem
|
||
toSQLFromItem alias = \case
|
||
RFDB (QDBPrimaryKey s) -> fromSelect $ DS.mkSQLSelect DS.JASSingleObject s
|
||
RFDB (QDBSimple s) -> fromSelect $ DS.mkSQLSelect DS.JASMultipleRows s
|
||
RFDB (QDBAggregation s) -> fromSelect $ DS.mkAggregateSelect s
|
||
RFDB (QDBConnection s) -> S.mkSelectWithFromItem (DS.mkConnectionSelect s) alias
|
||
RFAction s -> fromSelect $ DS.mkSQLSelect DS.JASSingleObject s
|
||
where
|
||
fromSelect s = S.mkSelFromItem s alias
|
||
|
||
mkMultiplexedQuery :: OMap.InsOrdHashMap G.Name SubscriptionRootFieldResolved -> MultiplexedQuery
|
||
mkMultiplexedQuery rootFields = MultiplexedQuery . Q.fromBuilder . toSQL $ S.mkSelect
|
||
{ S.selExtr =
|
||
-- SELECT _subs.result_id, _fld_resp.root AS result
|
||
[ S.Extractor (mkQualifiedIdentifier (Identifier "_subs") (Identifier "result_id")) Nothing
|
||
, S.Extractor (mkQualifiedIdentifier (Identifier "_fld_resp") (Identifier "root")) (Just . S.Alias $ Identifier "result") ]
|
||
, S.selFrom = Just $ S.FromExp [S.FIJoin $
|
||
S.JoinExpr subsInputFromItem S.LeftOuter responseLateralFromItem (S.JoinOn $ S.BELit True)]
|
||
}
|
||
where
|
||
-- FROM unnest($1::uuid[], $2::json[]) _subs (result_id, result_vars)
|
||
subsInputFromItem = S.FIUnnest
|
||
[S.SEPrep 1 `S.SETyAnn` S.TypeAnn "uuid[]", S.SEPrep 2 `S.SETyAnn` S.TypeAnn "json[]"]
|
||
(S.Alias $ Identifier "_subs")
|
||
[S.SEIdentifier $ Identifier "result_id", S.SEIdentifier $ Identifier "result_vars"]
|
||
|
||
-- LEFT OUTER JOIN LATERAL ( ... ) _fld_resp
|
||
responseLateralFromItem = S.mkLateralFromItem selectRootFields (S.Alias $ Identifier "_fld_resp")
|
||
selectRootFields = S.mkSelect
|
||
{ S.selExtr = [S.Extractor rootFieldsJsonAggregate (Just . S.Alias $ Identifier "root")]
|
||
, S.selFrom = Just . S.FromExp $
|
||
flip map (OMap.toList rootFields) $ \(fieldAlias, resolvedAST) ->
|
||
toSQLFromItem (S.Alias $ aliasToIdentifier fieldAlias) resolvedAST
|
||
}
|
||
|
||
-- json_build_object('field1', field1.root, 'field2', field2.root, ...)
|
||
rootFieldsJsonAggregate = S.SEFnApp "json_build_object" rootFieldsJsonPairs Nothing
|
||
rootFieldsJsonPairs = flip concatMap (OMap.keys rootFields) $ \fieldAlias ->
|
||
[ S.SELit (G.unName fieldAlias)
|
||
, mkQualifiedIdentifier (aliasToIdentifier fieldAlias) (Identifier "root") ]
|
||
|
||
mkQualifiedIdentifier prefix = S.SEQIdentifier . S.QIdentifier (S.QualifiedIdentifier prefix Nothing) -- TODO fix this Nothing of course
|
||
aliasToIdentifier = Identifier . G.unName
|
||
|
||
-- TODO fix this comment
|
||
-- | Resolves an 'GR.UnresolvedVal' by converting 'GR.UVPG' values to SQL expressions that refer to
|
||
-- the @result_vars@ input object, collecting variable values along the way.
|
||
resolveMultiplexedValue
|
||
:: (MonadState (HashMap G.Name PGColumnValue, Seq PGColumnValue) m)
|
||
=> UnpreparedValue -> m S.SQLExp
|
||
resolveMultiplexedValue = \case
|
||
UVParameter colVal varM -> do
|
||
varJsonPath <- case fmap PS.getName varM of
|
||
Just varName -> do
|
||
modifying _1 $ Map.insert varName colVal
|
||
pure ["query", G.unName varName]
|
||
Nothing -> do
|
||
syntheticVarIndex <- gets (length . snd)
|
||
modifying _2 (|> colVal)
|
||
pure ["synthetic", T.pack $ show syntheticVarIndex]
|
||
pure $ fromResVars (PGTypeScalar $ pstType $ pcvValue colVal) varJsonPath
|
||
UVSessionVar ty sessVar -> pure $ fromResVars ty ["session", sessionVariableToText sessVar]
|
||
UVLiteral sqlExp -> pure sqlExp
|
||
UVSession -> pure $ fromResVars (PGTypeScalar PGJSON) ["session"]
|
||
where
|
||
fromResVars pgType jPath = addTypeAnnotation pgType $ S.SEOpApp (S.SQLOp "#>>")
|
||
[ S.SEQIdentifier $ S.QIdentifier (S.QualifiedIdentifier (Identifier "_subs") Nothing) (Identifier "result_vars")
|
||
, S.SEArray $ map S.SELit jPath
|
||
]
|
||
addTypeAnnotation pgType = flip S.SETyAnn (S.mkTypeAnn pgType) . case pgType of
|
||
PGTypeScalar scalarType -> withConstructorFn scalarType
|
||
PGTypeArray _ -> id
|
||
|
||
newtype CohortId = CohortId { unCohortId :: UUID }
|
||
deriving (Show, Eq, Hashable, J.ToJSON, Q.FromCol)
|
||
|
||
newCohortId :: (MonadIO m) => m CohortId
|
||
newCohortId = CohortId <$> liftIO UUID.nextRandom
|
||
|
||
data CohortVariables
|
||
= CohortVariables
|
||
{ _cvSessionVariables :: !SessionVariables
|
||
, _cvQueryVariables :: !ValidatedQueryVariables
|
||
, _cvSyntheticVariables :: !ValidatedSyntheticVariables
|
||
-- ^ To allow more queries to be multiplexed together, we introduce “synthetic” variables for
|
||
-- /all/ SQL literals in a query, even if they don’t correspond to any GraphQL variable. For
|
||
-- example, the query
|
||
--
|
||
-- > subscription latest_tracks($condition: tracks_bool_exp!) {
|
||
-- > tracks(where: $tracks_bool_exp) {
|
||
-- > id
|
||
-- > title
|
||
-- > }
|
||
-- > }
|
||
--
|
||
-- might be executed with similar values for @$condition@, such as @{"album_id": {"_eq": "1"}}@
|
||
-- and @{"album_id": {"_eq": "2"}}@.
|
||
--
|
||
-- Normally, we wouldn’t bother parameterizing over the @1@ and @2@ literals in the resulting
|
||
-- query because we can’t cache that query plan (since different @$condition@ values could lead to
|
||
-- different SQL). However, for live queries, we can still take advantage of the similarity
|
||
-- between the two queries by multiplexing them together, so we replace them with references to
|
||
-- synthetic variables.
|
||
} deriving (Show, Eq, Generic)
|
||
instance Hashable CohortVariables
|
||
|
||
instance J.ToJSON CohortVariables where
|
||
toJSON (CohortVariables sessionVars queryVars syntheticVars) =
|
||
J.object ["session" J..= sessionVars, "query" J..= queryVars, "synthetic" J..= syntheticVars]
|
||
|
||
-- These types exist only to use the Postgres array encoding.
|
||
newtype CohortIdArray = CohortIdArray { unCohortIdArray :: [CohortId] }
|
||
deriving (Show, Eq)
|
||
instance Q.ToPrepArg CohortIdArray where
|
||
toPrepVal (CohortIdArray l) = Q.toPrepValHelper PTI.unknown encoder $ map unCohortId l
|
||
where
|
||
encoder = PE.array 2950 . PE.dimensionArray foldl' (PE.encodingArray . PE.uuid)
|
||
newtype CohortVariablesArray = CohortVariablesArray { unCohortVariablesArray :: [CohortVariables] }
|
||
deriving (Show, Eq)
|
||
instance Q.ToPrepArg CohortVariablesArray where
|
||
toPrepVal (CohortVariablesArray l) =
|
||
Q.toPrepValHelper PTI.unknown encoder (map J.toJSON l)
|
||
where
|
||
encoder = PE.array 114 . PE.dimensionArray foldl' (PE.encodingArray . PE.json_ast)
|
||
|
||
executeMultiplexedQuery
|
||
:: (MonadTx m) => MultiplexedQuery -> [(CohortId, CohortVariables)] -> m [(CohortId, B.ByteString)]
|
||
executeMultiplexedQuery (MultiplexedQuery query) = executeQuery query
|
||
|
||
-- | Internal; used by both 'executeMultiplexedQuery' and 'explainLiveQueryPlan'.
|
||
executeQuery :: (MonadTx m, Q.FromRow a) => Q.Query -> [(CohortId, CohortVariables)] -> m [a]
|
||
executeQuery query cohorts =
|
||
let (cohortIds, cohortVars) = unzip cohorts
|
||
preparedArgs = (CohortIdArray cohortIds, CohortVariablesArray cohortVars)
|
||
in liftTx $ Q.listQE defaultTxErrorHandler query preparedArgs True
|
||
|
||
-- -------------------------------------------------------------------------------------------------
|
||
-- Variable validation
|
||
|
||
-- | When running multiplexed queries, we have to be especially careful about user input, since
|
||
-- invalid values will cause the query to fail, causing collateral damage for anyone else
|
||
-- multiplexed into the same query. Therefore, we pre-validate variables against Postgres by
|
||
-- executing a no-op query of the shape
|
||
--
|
||
-- > SELECT 'v1'::t1, 'v2'::t2, ..., 'vn'::tn
|
||
--
|
||
-- so if any variable values are invalid, the error will be caught early.
|
||
newtype ValidatedVariables f = ValidatedVariables (f TxtEncodedPGVal)
|
||
deriving instance (Show (f TxtEncodedPGVal)) => Show (ValidatedVariables f)
|
||
deriving instance (Eq (f TxtEncodedPGVal)) => Eq (ValidatedVariables f)
|
||
deriving instance (Hashable (f TxtEncodedPGVal)) => Hashable (ValidatedVariables f)
|
||
deriving instance (J.ToJSON (f TxtEncodedPGVal)) => J.ToJSON (ValidatedVariables f)
|
||
|
||
type ValidatedQueryVariables = ValidatedVariables (Map.HashMap G.Name)
|
||
type ValidatedSyntheticVariables = ValidatedVariables []
|
||
|
||
-- | Checks if the provided arguments are valid values for their corresponding types.
|
||
-- Generates SQL of the format "select 'v1'::t1, 'v2'::t2 ..."
|
||
validateVariables
|
||
:: (Traversable f, MonadError QErr m, MonadIO m)
|
||
=> PGExecCtx
|
||
-> f (WithScalarType PGScalarValue)
|
||
-> m (ValidatedVariables f)
|
||
validateVariables pgExecCtx variableValues = do
|
||
let valSel = mkValidationSel $ toList variableValues
|
||
Q.Discard () <- runQueryTx_ $ liftTx $
|
||
Q.rawQE dataExnErrHandler (Q.fromBuilder $ toSQL valSel) [] False
|
||
pure . ValidatedVariables $ fmap (txtEncodedPGVal . pstValue) variableValues
|
||
where
|
||
mkExtrs = map (flip S.Extractor Nothing . toTxtValue)
|
||
mkValidationSel vars =
|
||
S.mkSelect { S.selExtr = mkExtrs vars }
|
||
runQueryTx_ tx = do
|
||
res <- liftIO $ runExceptT (runQueryTx pgExecCtx tx)
|
||
liftEither res
|
||
|
||
-- Explicitly look for the class of errors raised when the format of a value provided
|
||
-- for a type is incorrect.
|
||
dataExnErrHandler = mkTxErrorHandler (has _PGDataException)
|
||
|
||
-- -------------------------------------------------------------------------------------------------
|
||
-- Live query plans
|
||
|
||
-- | A self-contained, ready-to-execute live query plan. Contains enough information to find an
|
||
-- existing poller that this can be added to /or/ to create a new poller if necessary.
|
||
data LiveQueryPlan
|
||
= LiveQueryPlan
|
||
{ _lqpParameterizedPlan :: !ParameterizedLiveQueryPlan
|
||
, _lqpVariables :: !CohortVariables
|
||
} deriving Show
|
||
|
||
data ParameterizedLiveQueryPlan
|
||
= ParameterizedLiveQueryPlan
|
||
{ _plqpRole :: !RoleName
|
||
, _plqpQuery :: !MultiplexedQuery
|
||
} deriving (Show)
|
||
$(J.deriveToJSON (J.aesonDrop 4 J.snakeCase) ''ParameterizedLiveQueryPlan)
|
||
|
||
data ReusableLiveQueryPlan
|
||
= ReusableLiveQueryPlan
|
||
{ _rlqpParameterizedPlan :: !ParameterizedLiveQueryPlan
|
||
, _rlqpSyntheticVariableValues :: !ValidatedSyntheticVariables
|
||
, _rlqpQueryVariableTypes :: HashMap G.Name PGColumnType
|
||
} deriving (Show)
|
||
$(J.deriveToJSON (J.aesonDrop 4 J.snakeCase) ''ReusableLiveQueryPlan)
|
||
|
||
-- | Constructs a new execution plan for a live query and returns a reusable version of the plan if
|
||
-- possible.
|
||
|
||
-- NOTE: This function has a 'MonadTrace' constraint in master, but we don't need it
|
||
-- here. We should evaluate if we need it here.
|
||
buildLiveQueryPlan
|
||
:: ( MonadError QErr m
|
||
, MonadIO m
|
||
)
|
||
=> PGExecCtx
|
||
-> UserInfo
|
||
-> InsOrdHashMap G.Name (SubscriptionRootField UnpreparedValue)
|
||
-> m (LiveQueryPlan, Maybe ReusableLiveQueryPlan)
|
||
buildLiveQueryPlan pgExecCtx userInfo unpreparedAST = do
|
||
-- ((resolvedASTs, (queryVariableValues, syntheticVariableValues)), finalReusability) <-
|
||
-- GV.runReusabilityTWith initialReusability . flip runStateT mempty $
|
||
-- fmap Map.fromList . for (toList fields) $ \field -> case GV._fName field of
|
||
-- "__typename" -> throwVE "you cannot create a subscription on '__typename' field"
|
||
-- _ -> do
|
||
-- unresolvedAST <- GR.queryFldToPGAST field actionExecutioner
|
||
-- resolvedAST <- GR.traverseQueryRootFldAST resolveMultiplexedValue unresolvedAST
|
||
|
||
-- let (_, remoteJoins) = GR.toPGQuery resolvedAST
|
||
-- -- Reject remote relationships in subscription live query
|
||
-- when (remoteJoins /= mempty) $
|
||
-- throw400 NotSupported
|
||
-- "Remote relationships are not allowed in subscriptions"
|
||
-- pure (GV._fAlias field, resolvedAST)
|
||
|
||
-- Transform the RQL AST into a prepared SQL query
|
||
{- preparedAST <- for unpreparedAST \unpreparedQuery -> do
|
||
(preparedQuery, PlanningSt _ planVars planVals)
|
||
<- flip runStateT initPlanningSt
|
||
$ traverseSubscriptionRootField prepareWithPlan unpreparedQuery
|
||
pure $! irToRootFieldPlan planVars planVals preparedQuery
|
||
-}
|
||
(preparedAST, (queryVariableValues, querySyntheticVariableValues)) <- flip runStateT (mempty, Seq.empty) $
|
||
for unpreparedAST \unpreparedQuery -> do
|
||
resolvedRootField <- traverseQueryRootField resolveMultiplexedValue unpreparedQuery
|
||
case resolvedRootField of
|
||
RFDB qDB -> do
|
||
let remoteJoins = case qDB of
|
||
QDBSimple s -> snd $ RR.getRemoteJoins s
|
||
QDBPrimaryKey s -> snd $ RR.getRemoteJoins s
|
||
QDBAggregation s -> snd $ RR.getRemoteJoinsAggregateSelect s
|
||
QDBConnection s -> snd $ RR.getRemoteJoinsConnectionSelect s
|
||
when (remoteJoins /= mempty)
|
||
$ throw400 NotSupported "Remote relationships are not allowed in subscriptions"
|
||
_ -> pure ()
|
||
traverseAction (DS.traverseAnnSimpleSelect resolveMultiplexedValue . resolveAsyncActionQuery userInfo) resolvedRootField
|
||
|
||
let multiplexedQuery = mkMultiplexedQuery preparedAST
|
||
roleName = _uiRole userInfo
|
||
parameterizedPlan = ParameterizedLiveQueryPlan roleName multiplexedQuery
|
||
|
||
-- We need to ensure that the values provided for variables are correct according to Postgres.
|
||
-- Without this check an invalid value for a variable for one instance of the subscription will
|
||
-- take down the entire multiplexed query.
|
||
validatedQueryVars <- validateVariables pgExecCtx $ fmap pcvValue queryVariableValues
|
||
validatedSyntheticVars <- validateVariables pgExecCtx $ map pcvValue $ toList querySyntheticVariableValues
|
||
|
||
let -- TODO validatedQueryVars validatedSyntheticVars
|
||
cohortVariables = CohortVariables (_uiSession userInfo) validatedQueryVars validatedSyntheticVars
|
||
|
||
plan = LiveQueryPlan parameterizedPlan cohortVariables
|
||
-- See Note [Temporarily disabling query plan caching]
|
||
-- varTypes = finalReusability ^? GV._Reusable
|
||
reusablePlan = ReusableLiveQueryPlan parameterizedPlan validatedSyntheticVars mempty {- <$> _varTypes -}
|
||
pure (plan, Just reusablePlan)
|
||
|
||
-- (astResolved, (queryVariableValues, syntheticVariableValues)) <- flip runStateT mempty $
|
||
-- GEQ.traverseSubscriptionRootField resolveMultiplexedValue _astUnresolved
|
||
-- let pgQuery = mkMultiplexedQuery $ _toPGQuery astResolved
|
||
-- parameterizedPlan = ParameterizedLiveQueryPlan (userRole userInfo) fieldAlias pgQuery
|
||
|
||
-- -- We need to ensure that the values provided for variables
|
||
-- -- are correct according to Postgres. Without this check
|
||
-- -- an invalid value for a variable for one instance of the
|
||
-- -- subscription will take down the entire multiplexed query
|
||
-- validatedQueryVars <- validateVariables pgExecCtx queryVariableValues
|
||
-- validatedSyntheticVars <- validateVariables pgExecCtx (toList syntheticVariableValues)
|
||
-- let cohortVariables = CohortVariables (userVars userInfo) validatedQueryVars validatedSyntheticVars
|
||
-- plan = LiveQueryPlan parameterizedPlan cohortVariables
|
||
-- reusablePlan = ReusableLiveQueryPlan parameterizedPlan validatedSyntheticVars <$> _varTypes
|
||
-- pure (plan, reusablePlan)
|
||
|
||
-- See Note [Temporarily disabling query plan caching]
|
||
-- reuseLiveQueryPlan
|
||
-- :: (MonadError QErr m, MonadIO m)
|
||
-- => PGExecCtx
|
||
-- -> SessionVariables
|
||
-- -> Maybe GH.VariableValues
|
||
-- -> ReusableLiveQueryPlan
|
||
-- -> m LiveQueryPlan
|
||
-- reuseLiveQueryPlan pgExecCtx sessionVars queryVars reusablePlan = do
|
||
-- let ReusableLiveQueryPlan parameterizedPlan syntheticVars queryVarTypes = reusablePlan
|
||
-- annVarVals <- _validateVariablesForReuse queryVarTypes queryVars
|
||
-- validatedVars <- validateVariables pgExecCtx annVarVals
|
||
-- pure $ LiveQueryPlan parameterizedPlan (CohortVariables sessionVars validatedVars syntheticVars)
|
||
|
||
data LiveQueryPlanExplanation
|
||
= LiveQueryPlanExplanation
|
||
{ _lqpeSql :: !Text
|
||
, _lqpePlan :: ![Text]
|
||
} deriving (Show)
|
||
$(J.deriveToJSON (J.aesonDrop 5 J.snakeCase) ''LiveQueryPlanExplanation)
|
||
|
||
explainLiveQueryPlan :: (MonadTx m, MonadIO m) => LiveQueryPlan -> m LiveQueryPlanExplanation
|
||
explainLiveQueryPlan plan = do
|
||
let parameterizedPlan = _lqpParameterizedPlan plan
|
||
queryText = Q.getQueryText . unMultiplexedQuery $ _plqpQuery parameterizedPlan
|
||
-- CAREFUL!: an `EXPLAIN ANALYZE` here would actually *execute* this
|
||
-- query, maybe resulting in privilege escalation:
|
||
explainQuery = Q.fromText $ "EXPLAIN (FORMAT TEXT) " <> queryText
|
||
cohortId <- newCohortId
|
||
explanationLines <- map runIdentity <$> executeQuery explainQuery [(cohortId, _lqpVariables plan)]
|
||
pure $ LiveQueryPlanExplanation queryText explanationLines
|