graphql-engine/server/src-lib/Hasura/GraphQL/Execute/LiveQuery.hs

286 lines
8.9 KiB
Haskell

module Hasura.GraphQL.Execute.LiveQuery
( RefetchInterval
, refetchIntervalFromMilli
, LQM.BatchSize
, LQM.mkBatchSize
, LQM.MxOpts
, LQM.mkMxOpts
, LQF.FallbackOpts
, LQF.mkFallbackOpts
, LQOpts
, mkLQOpts
, LiveQueriesState
, initLiveQueriesState
, dumpLiveQueriesState
, LiveQueryOp
, LiveQueryId
, addLiveQuery
, removeLiveQuery
, SubsPlan
, subsOpFromPlan
, subsOpFromPGAST
) where
import Data.Has
import qualified Control.Concurrent.STM as STM
import qualified Data.Aeson as J
import qualified Data.HashMap.Strict as Map
import qualified Data.HashSet as Set
import qualified Data.Text as T
import qualified Database.PG.Query as Q
import qualified Database.PG.Query.Connection as Q
import qualified Language.GraphQL.Draft.Syntax as G
import qualified Hasura.GraphQL.Execute.LiveQuery.Fallback as LQF
import qualified Hasura.GraphQL.Execute.LiveQuery.Multiplexed as LQM
import qualified Hasura.GraphQL.Resolve as GR
import qualified Hasura.GraphQL.Transport.HTTP.Protocol as GH
import qualified Hasura.GraphQL.Validate as GV
import qualified Hasura.SQL.DML as S
import Hasura.Db
import Hasura.EncJSON
import Hasura.GraphQL.Execute.LiveQuery.Types
import Hasura.Prelude
import Hasura.RQL.DML.Select (asSingleRowJsonResp)
import Hasura.RQL.Types
import Hasura.SQL.Types
import Hasura.SQL.Value
data LQOpts
= LQOpts
{ _loMxOpts :: LQM.MxOpts
, _loFallbackOpts :: LQF.FallbackOpts
} deriving (Show, Eq)
mkLQOpts :: LQM.MxOpts -> LQF.FallbackOpts -> LQOpts
mkLQOpts = LQOpts
data LiveQueriesState
= LiveQueriesState
{ _lqsMultiplexed :: !LQM.LiveQueriesState
, _lqsFallback :: !LQF.LiveQueriesState
, _lqsPGExecTx :: !PGExecCtx
}
dumpLiveQueriesState
:: LiveQueriesState -> IO J.Value
dumpLiveQueriesState (LiveQueriesState mx fallback _) = do
mxJ <- LQM.dumpLiveQueriesState mx
fallbackJ <- LQF.dumpLiveQueriesState fallback
return $ J.object
[ "fallback" J..= fallbackJ
, "multiplexed" J..= mxJ
]
initLiveQueriesState
:: LQOpts
-> PGExecCtx
-> IO LiveQueriesState
initLiveQueriesState (LQOpts mxOpts fallbackOpts) pgExecCtx = do
(mxMap, fallbackMap) <- STM.atomically $
(,) <$> LQM.initLiveQueriesState mxOpts
<*> LQF.initLiveQueriesState fallbackOpts
return $ LiveQueriesState mxMap fallbackMap pgExecCtx
data LiveQueryOp
= LQMultiplexed !LQM.MxOp
| LQFallback !LQF.FallbackOp
data LiveQueryId
= LQIMultiplexed !LQM.LiveQueryId
| LQIFallback !LQF.LiveQueryId
addLiveQuery
:: LiveQueriesState
-> LiveQueryOp
-- the action to be executed when result changes
-> OnChange
-> IO LiveQueryId
addLiveQuery lqState liveQOp onResultAction =
case liveQOp of
LQMultiplexed mxOp ->
LQIMultiplexed <$> LQM.addLiveQuery pgExecCtx mxMap mxOp onResultAction
LQFallback fallbackOp ->
LQIFallback <$> LQF.addLiveQuery
pgExecCtx fallbackMap fallbackOp onResultAction
where
LiveQueriesState mxMap fallbackMap pgExecCtx = lqState
removeLiveQuery
:: LiveQueriesState
-- the query and the associated operation
-> LiveQueryId
-> IO ()
removeLiveQuery lqState = \case
LQIMultiplexed lqId -> LQM.removeLiveQuery mxMap lqId
LQIFallback lqId -> LQF.removeLiveQuery fallbackMap lqId
where
LiveQueriesState mxMap fallbackMap _ = lqState
data SubsPlan
= SubsPlan
{ _sfMxOpCtx :: !LQM.MxOpCtx
, _sfVariableTypes :: !GV.VarPGTypes
}
instance J.ToJSON SubsPlan where
toJSON (SubsPlan opCtx varTypes) =
J.object [ "mx_op_ctx" J..= opCtx
, "variable_types" J..= varTypes
]
collectNonNullableVars
:: (MonadState GV.VarPGTypes m)
=> GR.UnresolvedVal -> m GR.UnresolvedVal
collectNonNullableVars val = do
case val of
GR.UVPG annPGVal -> do
let GR.AnnPGVal varM isNullable colTy _ = annPGVal
case (varM, isNullable) of
(Just var, False) -> modify (Map.insert var colTy)
_ -> return ()
_ -> return ()
return val
type TextEncodedVariables
= Map.HashMap G.Variable TxtEncodedPGVal
toMultiplexedQueryVar
:: (MonadState GV.AnnPGVarVals m)
=> GR.UnresolvedVal -> m S.SQLExp
toMultiplexedQueryVar = \case
GR.UVPG annPGVal ->
let GR.AnnPGVal varM isNullable colTy colVal = annPGVal
in case (varM, isNullable) of
-- we don't check for nullability as
-- this is only used for reusable plans
-- the check has to be made before this
(Just var, _) -> do
modify $ Map.insert var (colTy, colVal)
return $ fromResVars colTy
[ "variables"
, G.unName $ G.unVariable var
]
_ -> return $ toTxtValue colTy colVal
-- TODO: check the logic around colTy and session variable's type
GR.UVSessVar colTy sessVar ->
return $ fromResVars colTy [ "user", T.toLower sessVar]
GR.UVSQL sqlExp -> return sqlExp
where
fromResVars colTy jPath =
S.withTyAnn colTy $ S.SEOpApp (S.SQLOp "#>>")
[ S.SEQIden $ S.QIden (S.QualIden $ Iden "_subs")
(Iden "result_vars")
, S.SEArray $ map S.SELit jPath
]
subsOpFromPGAST
:: ( MonadError QErr m
, MonadReader r m
, Has UserInfo r
, MonadIO m
)
=> PGExecCtx
-> GH.GQLReqUnparsed
-> [G.VariableDefinition]
-> (G.Alias, GR.QueryRootFldUnresolved)
-> m (LiveQueryOp, Maybe SubsPlan)
subsOpFromPGAST pgExecCtx reqUnparsed varDefs (fldAls, astUnresolved) = do
userInfo <- asks getter
(_, varTypes) <- flip runStateT mempty $ GR.traverseQueryRootFldAST
collectNonNullableVars astUnresolved
-- can the subscription be multiplexed?
if Set.fromList (Map.keys varTypes) == allVars
then mkMultiplexedOp userInfo varTypes
else mkFallbackOp userInfo
where
allVars = Set.fromList $ map G._vdVariable varDefs
-- multiplexed subscription
mkMultiplexedOp userInfo varTypes = do
(astResolved, annVarVals) <-
flip runStateT mempty $ GR.traverseQueryRootFldAST
toMultiplexedQueryVar astUnresolved
let mxOpCtx = LQM.mkMxOpCtx (userRole userInfo)
(GH._grQuery reqUnparsed) fldAls $
GR.toPGQuery astResolved
txtEncodedVars <- validateAnnVarValsOnPg pgExecCtx annVarVals
let mxOp = (mxOpCtx, userVars userInfo, txtEncodedVars)
return (LQMultiplexed mxOp, Just $ SubsPlan mxOpCtx varTypes)
-- fallback tx subscription
mkFallbackOp userInfo = do
(astResolved, prepArgs) <-
flip runStateT mempty $ GR.traverseQueryRootFldAST
GR.resolveValPrep astUnresolved
let tx = withUserInfo userInfo $ liftTx $
asSingleRowJsonResp (GR.toPGQuery astResolved) $ toList prepArgs
fallbackOp = LQF.mkFallbackOp userInfo reqUnparsed $ withAlias tx
return (LQFallback fallbackOp, Nothing)
fldAlsT = G.unName $ G.unAlias fldAls
withAlias tx =
encJFromAssocList . pure . (,) fldAlsT <$> tx
validateAnnVarValsOnPg
:: ( MonadError QErr m
, MonadIO m
)
=> PGExecCtx
-> GV.AnnPGVarVals
-> m TextEncodedVariables
validateAnnVarValsOnPg pgExecCtx annVarVals = do
let valSel = mkValidationSel $ Map.elems annVarVals
Q.Discard _ <- runTx' $ liftTx $
Q.rawQE valPgErrHandler (Q.fromBuilder $ toSQL valSel) [] False
return $ fmap (txtEncodedPGVal . snd) annVarVals
where
mkExtrs = map (flip S.Extractor Nothing . uncurry toTxtValue)
mkValidationSel vars =
S.mkSelect { S.selExtr = mkExtrs vars }
runTx' tx = do
res <- liftIO $ runExceptT (runLazyTx' pgExecCtx tx)
liftEither res
valPgErrHandler :: Q.PGTxErr -> QErr
valPgErrHandler txErr =
fromMaybe (defaultTxErrorHandler txErr) $ do
stmtErr <- Q.getPGStmtErr txErr
codeMsg <- getPGCodeMsg stmtErr
(qErrCode, qErrMsg) <- extractError codeMsg
return $ err400 qErrCode qErrMsg
where
getPGCodeMsg pged =
(,) <$> Q.edStatusCode pged <*> Q.edMessage pged
extractError = \case
-- invalid text representation
("22P02", msg) -> return (DataException, msg)
-- invalid parameter value
("22023", msg) -> return (DataException, msg)
-- invalid input values
("22007", msg) -> return (DataException, msg)
_ -> Nothing
-- use the existing plan and new variables to create a pg query
subsOpFromPlan
:: ( MonadError QErr m
, MonadIO m
)
=> PGExecCtx
-> UserVars
-> Maybe GH.VariableValues
-> SubsPlan
-> m LiveQueryOp
subsOpFromPlan pgExecCtx usrVars varValsM (SubsPlan mxOpCtx varTypes) = do
annVarVals <- GV.getAnnPGVarVals varTypes varValsM
txtEncodedVars <- validateAnnVarValsOnPg pgExecCtx annVarVals
return $ LQMultiplexed (mxOpCtx, usrVars, txtEncodedVars)