module LaunchDarkly.Server.Network.Streaming (streamingThread) where
import Data.Text (Text)
import qualified Data.Text as T
import Data.Attoparsec.Text as P hiding (Result, try)
import Control.Monad (void, mzero, forever)
import Control.Monad.Catch (Exception, MonadCatch, try)
import Control.Exception (throwIO)
import Data.ByteString (ByteString)
import qualified Data.ByteString as B
import Control.Applicative (many)
import Data.Text.Encoding (decodeUtf8, encodeUtf8)
import Data.HashMap.Strict (HashMap)
import Network.HTTP.Client (Manager, Response(..), Request, parseRequest, brRead, throwErrorStatusCodes)
import Control.Monad.Logger (MonadLogger, logInfo, logWarn, logError)
import Control.Monad.IO.Class (MonadIO, liftIO)
import Data.Generics.Product (getField)
import Data.Aeson (FromJSON, parseJSON, withObject, eitherDecode, (.:), fromJSON, Result(..))
import qualified Data.ByteString.Lazy as L
import GHC.Natural (Natural)
import GHC.Generics (Generic)
import Control.Monad.Catch (MonadMask)
import Control.Retry (RetryPolicyM, RetryStatus, fullJitterBackoff, capDelay, retrying)
import Network.HTTP.Types.Status (ok200)
import System.Timeout (timeout)
import LaunchDarkly.Server.Client.Internal (ClientI)
import LaunchDarkly.Server.Store.Internal (StoreHandle, StoreResult, initializeStore, insertFlag, deleteFlag, deleteSegment, insertSegment)
import LaunchDarkly.Server.Features (Flag, Segment)
import LaunchDarkly.Server.Network.Common (tryAuthorized, checkAuthorization, prepareRequest, withResponseGeneric, tryHTTP)
data PutBody = PutBody
{ flags :: !(HashMap Text Flag)
, segments :: !(HashMap Text Segment)
} deriving (Generic, Show, FromJSON)
data PathData d = PathData
{ path :: !Text
, pathData :: !d
} deriving (Generic, Show)
data PathVersion = PathVersion
{ path :: !Text
, version :: !Natural
} deriving (Generic, Show, FromJSON)
instance FromJSON a => FromJSON (PathData a) where
parseJSON = withObject "Put" $ \o -> do
pathData <- o .: "data"
path <- o .: "path"
pure $ PathData { path = path, pathData = pathData }
data SSE = SSE
{ name :: !Text
, buffer :: !Text
, lastEventId :: !(Maybe Text)
, retry :: !(Maybe Text)
} deriving (Generic, Show, Eq)
nameCharPredicate :: Char -> Bool
nameCharPredicate x = x /= '\r' && x /= ':' && x /= '\n'
anyCharPredicate :: Char -> Bool
anyCharPredicate x = x /= '\r' && x /= '\n'
endOfLineSSE :: Parser ()
endOfLineSSE = choice [void $ string "\r\n", void $ string "\r", void $ string "\n", endOfInput]
comment :: Parser ()
comment = char ':' >> P.takeWhile anyCharPredicate >> endOfLineSSE >> pure ()
parseField :: Parser (Text, Text)
parseField = do
fieldName <- P.takeWhile1 nameCharPredicate
void $ option ' ' $ char ':'
void $ option ' ' $ char ' '
fieldValue <- P.takeWhile anyCharPredicate
endOfLineSSE
pure (fieldName, fieldValue)
processField :: (Text, Text) -> SSE -> SSE
processField (fieldName, fieldValue) event = case fieldName of
"event" -> event { name = fieldValue }
"id" -> event { lastEventId = Just fieldValue }
"retry" -> event { retry = Just fieldValue }
"data" -> event { buffer = T.concat [ buffer event, if T.null (buffer event) then "" else "\n", fieldValue] }
_ -> event
parseEvent :: Parser SSE
parseEvent = do
fields <- many (many comment >> parseField >>= pure)
endOfLineSSE
let event = foldr processField (SSE "" "" mzero mzero) fields
if T.null (name event) || T.null (buffer event) then parseEvent else pure event
processPut :: (MonadIO m, MonadLogger m) => StoreHandle IO -> L.ByteString -> m ()
processPut store value = case eitherDecode value of
Right (PathData _ (PutBody flags segments)) -> do
$(logInfo) "initializing store with put"
liftIO (initializeStore store flags segments) >>= \case
Left err -> $(logError) $ T.append "store failed put: " err
_ -> pure ()
Left err -> $(logError) $ T.append "failed to parse put body" (T.pack err)
processPatch :: forall m. (MonadIO m, MonadLogger m) => StoreHandle IO -> L.ByteString -> m ()
processPatch store value = case eitherDecode value of
Right (PathData path body)
| T.isPrefixOf "/flags/" path -> insPatch "flag" path insertFlag (fromJSON body)
| T.isPrefixOf "/segments/" path -> insPatch "segment" path insertSegment (fromJSON body)
| otherwise -> $(logError) "unknown patch path"
Left err -> $(logError) $ T.append "failed to parse patch generic" (T.pack err)
where
insPatch :: Text -> Text -> (StoreHandle IO -> a -> StoreResult ()) -> Result a -> m ()
insPatch name _ _ (Error err) = $(logError) $ T.concat ["failed to parse patch ", name, ": ", T.pack err]
insPatch name path insert (Success item) = do
$(logInfo) $ T.concat ["patching ", name, " with path: ", path]
status <- liftIO $ insert store item
either (\err -> $(logError) $ T.concat ["store failed ", name, " patch: ", err]) pure status
processDelete :: forall m. (MonadIO m, MonadLogger m) => StoreHandle IO -> L.ByteString -> m ()
processDelete store value = case eitherDecode value :: Either String PathVersion of
Right (PathVersion path version)
| T.isPrefixOf "/flags/" path -> logDelete "flag" path (deleteFlag store (T.drop 7 path) version)
| T.isPrefixOf "/segments/" path -> logDelete "segment" path (deleteSegment store (T.drop 10 path) version)
| otherwise -> $(logError) "unknown delete path"
Left err -> $(logError) $ T.append "failed to parse delete" (T.pack err)
where logDelete :: Text -> Text -> StoreResult () -> m ()
logDelete name path action = do
$(logInfo) $ T.concat ["deleting ", name, " with path: ", path]
status <- liftIO action
either (\err -> $(logError) $ T.concat ["store failed ", name, " delete: ", err]) pure status
processEvent :: (MonadIO m, MonadLogger m) => StoreHandle IO -> Text -> L.ByteString -> m ()
processEvent store name value = case name of
"put" -> processPut store value
"patch" -> processPatch store value
"delete" -> processDelete store value
_ -> $(logWarn) "unknown event type"
data ReadE = ReadETimeout | ReadEClosed deriving (Show, Exception)
tryReadE :: MonadCatch m => m a -> m (Either ReadE a)
tryReadE = try
readWithException :: IO ByteString -> IO Text
readWithException body = timeout (1000000 * 300) (brRead body) >>= \case
Nothing -> throwIO ReadETimeout
Just bytes -> if bytes == B.empty then throwIO ReadEClosed else pure (decodeUtf8 bytes)
readStream :: (MonadIO m, MonadLogger m, MonadMask m) => IO ByteString -> StoreHandle IO -> m ()
readStream body store = loop "" where
loop initial = tryReadE (parseWith (liftIO $ readWithException body) parseEvent initial) >>= \case
(Left ReadETimeout) -> $(logError) "streaming connection unexpectedly closed"
(Left ReadEClosed) -> $(logError) "timeout waiting for SSE event"
(Right parsed) -> case parsed of
Done remaining event -> do
processEvent store (name event) (L.fromStrict $ encodeUtf8 $ buffer event)
loop remaining
Fail _ context err ->
$(logError) $ T.intercalate " " ["failed parsing SSE frame", T.pack $ show context, T.pack err]
Partial _ -> $(logError) "failed parsing SSE frame unexpected partial"
retryPolicy :: MonadIO m => RetryPolicyM m
retryPolicy = capDelay (3600 * 1000000) $ fullJitterBackoff (1 * 1000000)
handleStream :: (MonadIO m, MonadLogger m, MonadMask m) => Manager -> Request -> StoreHandle IO -> RetryStatus -> m Bool
handleStream manager request store _ = do
status <- tryHTTP $ withResponseGeneric request manager $ \response -> checkAuthorization response >>
if responseStatus response /= ok200 then throwErrorStatusCodes request response else
readStream (responseBody response) store
case status of
(Left err) -> $(logError) (T.intercalate " " ["HTTP Exception", T.pack $ show err]) >> pure True
(Right _) -> pure False
streamingThread :: (MonadIO m, MonadLogger m, MonadMask m) => Manager -> ClientI -> m ()
streamingThread manager client = do
let config = getField @"config" client; store = getField @"store" client;
req <- prepareRequest config <$> liftIO (parseRequest $ T.unpack (getField @"streamURI" config) ++ "/all")
tryAuthorized client $ forever $ retrying retryPolicy (\_ status -> pure status) $ handleStream manager req store