graphql-engine/server/src-lib/Hasura/GraphQL/Transport/WebSocket/Server.hs
Robert 11a454c2d6 server, pro: actually reformat the code-base using ormolu
This commit applies ormolu to the whole Haskell code base by running `make format`.

For in-flight branches, simply merging changes from `main` will result in merge conflicts.
To avoid this, update your branch using the following instructions. Replace `<format-commit>`
by the hash of *this* commit.

$ git checkout my-feature-branch
$ git merge <format-commit>^    # and resolve conflicts normally
$ make format
$ git commit -a -m "reformat with ormolu"
$ git merge -s ours post-ormolu

https://github.com/hasura/graphql-engine-mono/pull/2404

GitOrigin-RevId: 75049f5c12f430c615eafb4c6b8e83e371e01c8e
2021-09-23 22:57:37 +00:00

415 lines
16 KiB
Haskell

{-# LANGUAGE NondecreasingIndentation #-}
{-# LANGUAGE OverloadedStrings #-}
module Hasura.GraphQL.Transport.WebSocket.Server where
import Control.Concurrent.Async qualified as A
import Control.Concurrent.Async.Lifted.Safe qualified as LA
import Control.Concurrent.STM qualified as STM
import Control.Exception.Lifted
import Control.Monad.Trans.Control qualified as MC
import Data.Aeson qualified as J
import Data.Aeson.Casing qualified as J
import Data.Aeson.TH qualified as J
import Data.ByteString.Char8 qualified as B
import Data.ByteString.Lazy qualified as BL
import Data.CaseInsensitive qualified as CI
import Data.String
import Data.TByteString qualified as TBS
import Data.UUID qualified as UUID
import Data.UUID.V4 qualified as UUID
import Data.Word (Word16)
import GHC.AssertNF.CPP
import GHC.Int (Int64)
import Hasura.GraphQL.ParameterizedQueryHash (ParameterizedQueryHash)
import Hasura.GraphQL.Transport.HTTP.Protocol
import Hasura.GraphQL.Transport.WebSocket.Protocol
import Hasura.Logging qualified as L
import Hasura.Prelude
import Hasura.Server.Init.Config (WSConnectionInitTimeout (..))
import ListT qualified
import Network.Wai.Extended (IpAddress)
import Network.WebSockets qualified as WS
import StmContainers.Map qualified as STMMap
import System.IO.Error qualified as E
newtype WSId = WSId {unWSId :: UUID.UUID}
deriving (Show, Eq, Hashable)
instance J.ToJSON WSId where
toJSON (WSId uuid) =
J.toJSON $ UUID.toText uuid
-- | Websocket message and other details
data MessageDetails = MessageDetails
{ _mdMessage :: !TBS.TByteString,
_mdMessageSize :: !Int64
}
deriving (Show, Eq)
$(J.deriveToJSON hasuraJSON ''MessageDetails)
data WSEvent
= EConnectionRequest
| EAccepted
| ERejected
| EMessageReceived !MessageDetails
| EMessageSent !MessageDetails
| EJwtExpired
| ECloseReceived
| ECloseSent !TBS.TByteString
| EClosed
deriving (Show, Eq)
$( J.deriveToJSON
J.defaultOptions
{ J.constructorTagModifier = J.snakeCase . drop 1,
J.sumEncoding = J.TaggedObject "type" "detail"
}
''WSEvent
)
-- extra websocket event info
data WSEventInfo = WSEventInfo
{ _wseiEventType :: !(Maybe ServerMsgType),
_wseiOperationId :: !(Maybe OperationId),
_wseiOperationName :: !(Maybe OperationName),
_wseiQueryExecutionTime :: !(Maybe Double),
_wseiResponseSize :: !(Maybe Int64),
_wseiParameterizedQueryHash :: !(Maybe ParameterizedQueryHash)
}
deriving (Show, Eq)
$( J.deriveToJSON
J.defaultOptions
{ J.fieldLabelModifier = J.snakeCase . drop 5,
J.omitNothingFields = True
}
''WSEventInfo
)
data WSLog = WSLog
{ _wslWebsocketId :: !WSId,
_wslEvent :: !WSEvent,
_wslMetadata :: !(Maybe WSEventInfo)
}
deriving (Show, Eq)
$( J.deriveToJSON
J.defaultOptions
{ J.fieldLabelModifier = J.snakeCase . drop 4,
J.omitNothingFields = True
}
''WSLog
)
class Monad m => MonadWSLog m where
-- | Takes WS server log data and logs it
-- logWSServer
logWSLog :: L.Logger L.Hasura -> WSLog -> m ()
instance MonadWSLog m => MonadWSLog (ExceptT e m) where
logWSLog l ws = lift $ logWSLog l ws
instance MonadWSLog m => MonadWSLog (ReaderT r m) where
logWSLog l ws = lift $ logWSLog l ws
instance L.ToEngineLog WSLog L.Hasura where
toEngineLog wsLog =
(L.LevelDebug, L.ELTInternal L.ILTWsServer, J.toJSON wsLog)
data WSQueueResponse = WSQueueResponse
{ _wsqrMessage :: !BL.ByteString,
-- | extra metadata that we use for other actions, such as print log
-- we don't want to inlcude them into websocket message payload
_wsqrEventInfo :: !(Maybe WSEventInfo)
}
data WSConn a = WSConn
{ _wcConnId :: !WSId,
_wcLogger :: !(L.Logger L.Hasura),
_wcConnRaw :: !WS.Connection,
_wcSendQ :: !(STM.TQueue WSQueueResponse),
_wcExtraData :: !a
}
getRawWebSocketConnection :: WSConn a -> WS.Connection
getRawWebSocketConnection = _wcConnRaw
getData :: WSConn a -> a
getData = _wcExtraData
getWSId :: WSConn a -> WSId
getWSId = _wcConnId
closeConn :: WSConn a -> BL.ByteString -> IO ()
closeConn wsConn = closeConnWithCode wsConn 1000 -- 1000 is "normal close"
-- | Closes a connection with code 1012, which means "Server is restarting"
-- good clients will implement a retry logic with a backoff of a few seconds
forceConnReconnect :: MonadIO m => WSConn a -> BL.ByteString -> m ()
forceConnReconnect wsConn bs = liftIO $ closeConnWithCode wsConn 1012 bs
closeConnWithCode :: WSConn a -> Word16 -> BL.ByteString -> IO ()
closeConnWithCode wsConn code bs = do
(L.unLogger . _wcLogger) wsConn $
WSLog (_wcConnId wsConn) (ECloseSent $ TBS.fromLBS bs) Nothing
WS.sendCloseCode (_wcConnRaw wsConn) code bs
-- writes to a queue instead of the raw connection
-- so that sendMsg doesn't block
sendMsg :: WSConn a -> WSQueueResponse -> IO ()
sendMsg wsConn !resp = do
$assertNFHere resp -- so we don't write thunks to mutable vars
STM.atomically $ STM.writeTQueue (_wcSendQ wsConn) resp
type ConnMap a = STMMap.Map WSId (WSConn a)
data ServerStatus a
= AcceptingConns !(ConnMap a)
| ShuttingDown
data WSServer a = WSServer
{ _wssLogger :: !(L.Logger L.Hasura),
-- | See e.g. createServerApp.onAccept for how we use STM to preserve consistency
_wssStatus :: !(STM.TVar (ServerStatus a))
}
createWSServer :: L.Logger L.Hasura -> STM.STM (WSServer a)
createWSServer logger = do
connMap <- STMMap.new
serverStatus <- STM.newTVar (AcceptingConns connMap)
return $ WSServer logger serverStatus
closeAll :: WSServer a -> BL.ByteString -> IO ()
closeAll (WSServer (L.Logger writeLog) serverStatus) msg = do
writeLog $ L.debugT "closing all connections"
conns <- STM.atomically $ flushConnMap serverStatus
closeAllWith (flip closeConn) msg conns
closeAllWith ::
(BL.ByteString -> WSConn a -> IO ()) ->
BL.ByteString ->
[(WSId, WSConn a)] ->
IO ()
closeAllWith closer msg conns =
void $ A.mapConcurrently (closer msg . snd) conns
-- | Resets the current connections map to an empty one if the server is
-- running and returns the list of connections that were in the map
-- before flushing it.
flushConnMap :: STM.TVar (ServerStatus a) -> STM.STM [(WSId, WSConn a)]
flushConnMap serverStatus = do
status <- STM.readTVar serverStatus
case status of
AcceptingConns connMap -> do
conns <- ListT.toList $ STMMap.listT connMap
STMMap.reset connMap
return conns
ShuttingDown -> return []
data AcceptWith a = AcceptWith
{ _awData :: !a,
_awReq :: !WS.AcceptRequest,
_awKeepAlive :: !(WSConn a -> IO ()),
_awOnJwtExpiry :: !(WSConn a -> IO ())
}
-- | These set of functions or message handlers is used by the
-- server while communicating with the client. They are particularly
-- useful for the case when the messages being sent to the client
-- are different for each of the sub-protocol(s) supported by the server.
type WSKeepAliveMessageAction a = WSConn a -> IO ()
type WSPostExecErrMessageAction a = WSConn a -> OperationId -> GQExecError -> IO ()
type WSOnErrorMessageAction a = WSConn a -> ConnErrMsg -> Maybe String -> IO ()
type WSCloseConnAction a = WSConn a -> OperationId -> String -> IO ()
-- | Used for specific actions within the `onConn` and `onMessage` handlers
data WSActions a = WSActions
{ _wsaPostExecErrMessageAction :: !(WSPostExecErrMessageAction a),
_wsaOnErrorMessageAction :: !(WSOnErrorMessageAction a),
_wsaConnectionCloseAction :: !(WSCloseConnAction a),
-- | NOTE: keep alive action was made redundant because we need to send this message
-- after the connection has been successfully established after `connection_init`
_wsaKeepAliveAction :: !(WSKeepAliveMessageAction a),
_wsaGetDataMessageType :: !(DataMsg -> ServerMsg),
_wsaAcceptRequest :: !WS.AcceptRequest
}
-- | to be used with `WSOnErrorMessageAction`
onClientMessageParseErrorText :: Maybe String
onClientMessageParseErrorText = Just "Parsing client message failed: "
-- | to be used with `WSOnErrorMessageAction`
onConnInitErrorText :: Maybe String
onConnInitErrorText = Just "Connection initialization failed: "
type OnConnH m a = WSId -> WS.RequestHead -> IpAddress -> WSActions a -> m (Either WS.RejectRequest (AcceptWith a))
type OnMessageH m a = WSConn a -> BL.ByteString -> WSActions a -> m ()
type OnCloseH m a = WSConn a -> m ()
-- | aka generalized 'WS.ServerApp' over @m@, which takes an IPAddress
type HasuraServerApp m = IpAddress -> WS.PendingConnection -> m ()
-- | NOTE: The types of `_hOnConn` and `_hOnMessage` were updated from `OnConnH` and `OnMessageH`
-- because we needed to pass the subprotcol here to these methods to eventually get to `OnConnH` and `OnMessageH`.
-- Please see `createServerApp` to get a better understanding of how these handlers are used.
data WSHandlers m a = WSHandlers
{ _hOnConn :: (WSId -> WS.RequestHead -> IpAddress -> WSSubProtocol -> m (Either WS.RejectRequest (AcceptWith a))),
_hOnMessage :: (WSConn a -> BL.ByteString -> WSSubProtocol -> m ()),
_hOnClose :: OnCloseH m a
}
createServerApp ::
(MonadIO m, MC.MonadBaseControl IO m, LA.Forall (LA.Pure m), MonadWSLog m) =>
WSConnectionInitTimeout ->
WSServer a ->
-- | user provided handlers
WSHandlers m a ->
-- | aka WS.ServerApp
HasuraServerApp m
{-# INLINE createServerApp #-}
createServerApp wsConnInitTimeout (WSServer logger@(L.Logger writeLog) serverStatus) wsHandlers !ipAddress !pendingConn = do
wsId <- WSId <$> liftIO UUID.nextRandom
logWSLog logger $ WSLog wsId EConnectionRequest Nothing
-- NOTE: this timer is specific to `graphql-ws`. the server has to close the connection
-- if the client doesn't send a `connection_init` message within the timeout period
wsConnInitTimer <- liftIO $ getNewWSTimer (unWSConnectionInitTimeout wsConnInitTimeout)
status <- liftIO $ STM.readTVarIO serverStatus
case status of
AcceptingConns _ -> logUnexpectedExceptions $ do
onConnRes <- connHandler wsId reqHead ipAddress subProtocol
either (onReject wsId) (onAccept wsConnInitTimer wsId) onConnRes
ShuttingDown ->
onReject wsId shuttingDownReject
where
reqHead = WS.pendingRequest pendingConn
getSubProtocolHeader rhdrs =
filter (\(x, _) -> x == (CI.mk . B.pack $ "Sec-WebSocket-Protocol")) $ WS.requestHeaders rhdrs
subProtocol = case getSubProtocolHeader reqHead of
[sph] -> toWSSubProtocol . B.unpack . snd $ sph
_ -> Apollo -- NOTE: we default to the apollo implemenation
connHandler = _hOnConn wsHandlers
messageHandler = _hOnMessage wsHandlers
closeHandler = _hOnClose wsHandlers
-- It's not clear what the unexpected exception handling story here should be. So at
-- least log properly and re-raise:
logUnexpectedExceptions = handle $ \(e :: SomeException) -> do
writeLog $
L.UnstructuredLog L.LevelError $
fromString $
"Unexpected exception raised in websocket. Please report this as a bug: " <> show e
throwIO e
shuttingDownReject =
WS.RejectRequest
503
"Service Unavailable"
[("Retry-After", "0")]
"Server is shutting down"
onReject wsId rejectRequest = do
liftIO $ WS.rejectRequestWith pendingConn rejectRequest
logWSLog logger $ WSLog wsId ERejected Nothing
onAccept wsConnInitTimer wsId (AcceptWith a acceptWithParams keepAlive onJwtExpiry) = do
conn <- liftIO $ WS.acceptRequestWith pendingConn acceptWithParams
logWSLog logger $ WSLog wsId EAccepted Nothing
sendQ <- liftIO STM.newTQueueIO
let !wsConn = WSConn wsId logger conn sendQ a
-- TODO there are many thunks here. Difficult to trace how much is retained, and
-- how much of that would be shared anyway.
-- Requires a fork of 'wai-websockets' and 'websockets', it looks like.
-- Adding `package` stanzas with -Xstrict -XStrictData for those two packages
-- helped, cutting the number of thunks approximately in half.
liftIO $ $assertNFHere wsConn -- so we don't write thunks to mutable vars
let whenAcceptingInsertConn = liftIO $
STM.atomically $ do
status <- STM.readTVar serverStatus
case status of
ShuttingDown -> pure ()
AcceptingConns connMap -> STMMap.insert wsConn wsId connMap
return status
-- ensure we clean up connMap even if an unexpected exception is raised from our worker
-- threads, or an async exception is raised somewhere in the body here:
bracket
whenAcceptingInsertConn
(onConnClose wsConn)
$ \case
ShuttingDown -> do
-- Bad luck, we were in the process of shutting the server down but a new
-- connection was accepted. Let's just close it politely
forceConnReconnect wsConn "shutting server down"
closeHandler wsConn
AcceptingConns _ -> do
let rcv = forever $ do
-- Process all messages serially (important!), in a separate thread:
msg <-
liftIO $
-- Re-throw "receiveloop: resource vanished (Connection reset by peer)" :
-- https://github.com/yesodweb/wai/blob/master/warp/Network/Wai/Handler/Warp/Recv.hs#L112
-- as WS exception signaling cleanup below. It's not clear why exactly this gets
-- raised occasionally; I suspect an equivalent handler is missing from WS itself.
-- Regardless this should be safe:
handleJust (guard . E.isResourceVanishedError) (\() -> throw WS.ConnectionClosed) $
WS.receiveData conn
let message = MessageDetails (TBS.fromLBS msg) (BL.length msg)
logWSLog logger $ WSLog wsId (EMessageReceived message) Nothing
messageHandler wsConn msg subProtocol
let send = forever $ do
WSQueueResponse msg wsInfo <- liftIO $ STM.atomically $ STM.readTQueue sendQ
let message = MessageDetails (TBS.fromLBS msg) (BL.length msg)
liftIO $ WS.sendTextData conn msg
logWSLog logger $ WSLog wsId (EMessageSent message) wsInfo
-- withAsync lets us be very sure that if e.g. an async exception is raised while we're
-- forking that the threads we launched will be cleaned up. See also below.
LA.withAsync rcv $ \rcvRef -> do
LA.withAsync send $ \sendRef -> do
LA.withAsync (liftIO $ keepAlive wsConn) $ \keepAliveRef -> do
LA.withAsync (liftIO $ onJwtExpiry wsConn) $ \onJwtExpiryRef -> do
-- once connection is accepted, check the status of the timer, and if it's expired, close the connection for `graphql-ws`
timeoutStatus <- liftIO $ getWSTimerState wsConnInitTimer
when (timeoutStatus == Done && subProtocol == GraphQLWS) $
liftIO $ closeConnWithCode wsConn 4408 "Connection initialisation timed out"
-- terminates on WS.ConnectionException and JWT expiry
let waitOnRefs = [keepAliveRef, onJwtExpiryRef, rcvRef, sendRef]
-- withAnyCancel re-raises exceptions from forkedThreads, and is guarenteed to cancel in
-- case of async exceptions raised while blocking here:
try (LA.waitAnyCancel waitOnRefs) >>= \case
-- NOTE: 'websockets' is a bit of a rat's nest at the moment wrt
-- exceptions; for now handle all ConnectionException by closing
-- and cleaning up, see: https://github.com/jaspervdj/websockets/issues/48
Left (_ :: WS.ConnectionException) -> do
logWSLog logger $ WSLog (_wcConnId wsConn) ECloseReceived Nothing
-- this will happen when jwt is expired
Right _ -> do
logWSLog logger $ WSLog (_wcConnId wsConn) EJwtExpired Nothing
onConnClose wsConn = \case
ShuttingDown -> pure ()
AcceptingConns connMap -> do
liftIO $ STM.atomically $ STMMap.delete (_wcConnId wsConn) connMap
closeHandler wsConn
logWSLog logger $ WSLog (_wcConnId wsConn) EClosed Nothing
shutdown :: WSServer a -> IO ()
shutdown (WSServer (L.Logger writeLog) serverStatus) = do
writeLog $ L.debugT "Shutting websockets server down"
conns <- STM.atomically $ do
conns <- flushConnMap serverStatus
STM.writeTVar serverStatus ShuttingDown
return conns
closeAllWith (flip forceConnReconnect) "shutting server down" conns