graphql-engine/server/src-lib/Hasura/GraphQL/Explain.hs
Alexis King e01008413e
Track variable uses within query validation for caching (fix #3097) (#3135)
This fix is a little ugly, but it’s the only simple solution without a
significant refactoring that restructures the relationship between
GraphQL/Validate and GraphQL/Resolve. The ugliness should go away if we
implement something like #2801.
2019-10-16 09:33:34 -05:00

137 lines
4.7 KiB
Haskell

module Hasura.GraphQL.Explain
( explainGQLQuery
, GQLExplain
) where
import qualified Data.Aeson as J
import qualified Data.Aeson.Casing as J
import qualified Data.Aeson.TH as J
import qualified Data.HashMap.Strict as Map
import qualified Database.PG.Query as Q
import qualified Language.GraphQL.Draft.Syntax as G
import Hasura.EncJSON
import Hasura.GraphQL.Context
import Hasura.GraphQL.Validate.Types (evalReusabilityT,
runReusabilityT)
import Hasura.Prelude
import Hasura.RQL.DML.Internal
import Hasura.RQL.Types
import Hasura.SQL.Types
import Hasura.SQL.Value
import qualified Hasura.GraphQL.Execute as E
import qualified Hasura.GraphQL.Execute.LiveQuery as E
import qualified Hasura.GraphQL.Resolve as RS
import qualified Hasura.GraphQL.Transport.HTTP.Protocol as GH
import qualified Hasura.GraphQL.Validate as GV
import qualified Hasura.SQL.DML as S
data GQLExplain
= GQLExplain
{ _gqeQuery :: !GH.GQLReqParsed
, _gqeUser :: !(Maybe (Map.HashMap Text Text))
} deriving (Show, Eq)
$(J.deriveJSON (J.aesonDrop 4 J.camelCase){J.omitNothingFields=True}
''GQLExplain
)
data FieldPlan
= FieldPlan
{ _fpField :: !G.Name
, _fpSql :: !(Maybe Text)
, _fpPlan :: !(Maybe [Text])
} deriving (Show, Eq)
$(J.deriveJSON (J.aesonDrop 3 J.camelCase) ''FieldPlan)
type Explain r =
(ReaderT r (Except QErr))
runExplain
:: (MonadError QErr m)
=> r -> Explain r a -> m a
runExplain ctx m =
either throwError return $ runExcept $ runReaderT m ctx
resolveVal
:: (MonadError QErr m)
=> UserInfo -> RS.UnresolvedVal -> m S.SQLExp
resolveVal userInfo = \case
RS.UVPG annPGVal ->
RS.txtConverter annPGVal
RS.UVSessVar ty sessVar -> do
sessVarVal <- S.SELit <$> getSessVarVal userInfo sessVar
return $ flip S.SETyAnn (S.mkTypeAnn ty) $ case ty of
PGTypeScalar colTy -> withConstructorFn colTy sessVarVal
PGTypeArray _ -> sessVarVal
RS.UVSQL sqlExp -> return sqlExp
getSessVarVal
:: (MonadError QErr m)
=> UserInfo -> SessVar -> m SessVarVal
getSessVarVal userInfo sessVar =
onNothing (getVarVal sessVar usrVars) $
throw400 UnexpectedPayload $
"missing required session variable for role " <> rn <<>
" : " <> sessVar
where
rn = userRole userInfo
usrVars = userVars userInfo
explainField
:: (MonadTx m)
=> UserInfo -> GCtx -> SQLGenCtx -> GV.Field -> m FieldPlan
explainField userInfo gCtx sqlGenCtx fld =
case fName of
"__type" -> return $ FieldPlan fName Nothing Nothing
"__schema" -> return $ FieldPlan fName Nothing Nothing
"__typename" -> return $ FieldPlan fName Nothing Nothing
_ -> do
unresolvedAST <-
runExplain (queryCtxMap, userInfo, fldMap, orderByCtx, sqlGenCtx) $
evalReusabilityT $ RS.queryFldToPGAST fld
resolvedAST <- RS.traverseQueryRootFldAST (resolveVal userInfo)
unresolvedAST
let txtSQL = Q.getQueryText $ RS.toPGQuery resolvedAST
withExplain = "EXPLAIN (FORMAT TEXT) " <> txtSQL
planLines <- liftTx $ map runIdentity <$>
Q.listQE dmlTxErrorHandler (Q.fromText withExplain) () True
return $ FieldPlan fName (Just txtSQL) $ Just planLines
where
fName = GV._fName fld
queryCtxMap = _gQueryCtxMap gCtx
fldMap = _gFields gCtx
orderByCtx = _gOrdByCtx gCtx
explainGQLQuery
:: (MonadError QErr m, MonadIO m)
=> PGExecCtx
-> SchemaCache
-> SQLGenCtx
-> Bool
-> GQLExplain
-> m EncJSON
explainGQLQuery pgExecCtx sc sqlGenCtx enableAL (GQLExplain query userVarsRaw) = do
(execPlan, queryReusability) <- runReusabilityT $
E.getExecPlanPartial userInfo sc enableAL query
(gCtx, rootSelSet) <- case execPlan of
E.GExPHasura (gCtx, rootSelSet) ->
return (gCtx, rootSelSet)
E.GExPRemote _ _ ->
throw400 InvalidParams "only hasura queries can be explained"
case rootSelSet of
GV.RQuery selSet ->
runInTx $ encJFromJValue <$> traverse (explainField userInfo gCtx sqlGenCtx) (toList selSet)
GV.RMutation _ ->
throw400 InvalidParams "only queries can be explained"
GV.RSubscription rootField -> do
(plan, _) <- E.getSubsOp pgExecCtx gCtx sqlGenCtx userInfo queryReusability rootField
runInTx $ encJFromJValue <$> E.explainLiveQueryPlan plan
where
usrVars = mkUserVars $ maybe [] Map.toList userVarsRaw
userInfo = mkUserInfo (fromMaybe adminRole $ roleFromVars usrVars) usrVars
runInTx = liftEither <=< liftIO . runExceptT . runLazyTx pgExecCtx