Lazier metadata loading

Data/Hackage.hs

@@ -14,7 +14,8 @@ import Types
 import Data.BlobStore
 import Data.Conduit.Lazy (MonadActive (..), lazyConsume)
 import qualified Codec.Archive.Tar as Tar
-import Control.Monad.Reader (MonadReader, ask)
+import Control.Monad.Reader (MonadReader, ask, runReaderT)
+import Control.Monad.Logger (runNoLoggingT)
 import qualified Data.Text as T
 import Data.Conduit.Zlib (ungzip, gzip)
 import System.IO.Temp (withSystemTempFile, withSystemTempDirectory)
@@ -35,6 +36,7 @@ import Data.Byteable (toBytes)
 import Distribution.Text (display)
 import Text.Markdown (Markdown (Markdown))
 import Data.Foldable (foldMap)
+import qualified Data.Traversable as T
 
 sinkUploadHistory :: Monad m => Consumer (Entity Uploaded) m UploadHistory
 sinkUploadHistory =
@@ -58,8 +60,8 @@ loadCabalFiles :: ( MonadActive m
                   )
                => UploadHistory -- ^ initial
                -> HashMap PackageName (Version, ByteString)
-               -> m UploadState
+               -> m (UploadState Metadata)
-loadCabalFiles uploadHistory0 metadata0 = flip execStateT (UploadState uploadHistory0 [] metadata0 mempty) $ do
+loadCabalFiles uploadHistory0 metadata0 = (>>= runUploadState) $ flip execStateT (UploadState uploadHistory0 [] metadata0 mempty) $ do
     HackageRoot root <- liftM getHackageRoot ask
     $logDebug $ "Entering loadCabalFiles, root == " ++ root
     req <- parseUrl $ unpack $ root ++ "/00-index.tar.gz"
@@ -102,6 +104,9 @@ loadCabalFiles uploadHistory0 metadata0 = flip execStateT (UploadState uploadHis
                               $ parsePackageDescription $ unpack $ decodeUtf8 lbs
             _ -> return ()
 
+runUploadState :: MonadIO m => UploadState (IO a) -> m (UploadState a)
+runUploadState (UploadState w x y z) = liftIO $ UploadState w x y <$> T.sequence z
+
 tarSource :: (Exception e, MonadThrow m)
           => Tar.Entries e
           -> Producer m Tar.Entry
@@ -110,18 +115,18 @@ tarSource (Tar.Fail e) = throwM e
 tarSource (Tar.Next e es) = yield e >> tarSource es
 
 type UploadHistory = HashMap PackageName (HashMap Version UTCTime)
-data UploadState = UploadState
+data UploadState md = UploadState
     { usHistory :: !UploadHistory
     , usChanges :: ![Uploaded]
     , usMetadata :: !(HashMap PackageName (Version, ByteString))
-    , usMetaChanges :: !(HashMap PackageName Metadata)
+    , usMetaChanges :: !(HashMap PackageName md)
     }
 
 setUploadDate :: ( MonadBaseControl IO m
                  , MonadThrow m
                  , MonadIO m
                  , MonadReader env m
-                 , MonadState UploadState m
+                 , MonadState (UploadState (IO Metadata)) m
                  , HasHttpManager env
                  , MonadLogger m
                  )
@@ -157,7 +162,7 @@ setMetadata :: ( MonadBaseControl IO m
                , MonadThrow m
                , MonadIO m
                , MonadReader env m
-               , MonadState UploadState m
+               , MonadState (UploadState (IO Metadata)) m
                , HasHttpManager env
                , MonadLogger m
                , MonadActive m
@@ -203,9 +208,11 @@ getMetadata :: ( MonadActive m
             -> Version
             -> ByteString
             -> PD.GenericPackageDescription
-            -> m Metadata
+            -> m (IO Metadata)
 getMetadata name version hash' gpd = do
     let pd = PD.packageDescription gpd
+    env <- ask
+    return $ liftIO $ runNoLoggingT $ flip runReaderT env $ do
         (mreadme, mchangelog, mlicenseContent) <-
             grabExtraFiles name version $ PD.licenseFiles pd
         return Metadata