feat(users/Profpatsch): init whatcd-resolver

Change-Id: Ieb377fb8caa60e716703153dfeca5173f9a6779d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8830
Reviewed-by: Profpatsch <mail@profpatsch.de>
Tested-by: BuildkiteCI

users/Profpatsch/whatcd-resolver/src/WhatcdResolver.hs

@@ -0,0 +1,303 @@
+{-# LANGUAGE DeriveAnyClass #-}
+{-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE QuasiQuotes #-}
+
+module WhatcdResolver where
+
+import Control.Monad.Logger qualified as Logger
+import Control.Monad.Logger.CallStack
+import Control.Monad.Reader
+import Data.Aeson qualified as Json
+import Data.Aeson.BetterErrors qualified as Json
+import Data.Aeson.KeyMap qualified as KeyMap
+import Data.Error.Tree
+import Data.List.NonEmpty qualified as NonEmpty
+import Data.Map.Strict qualified as Map
+import Data.Pool (Pool)
+import Data.Pool qualified as Pool
+import Data.Text qualified as Text
+import Database.PostgreSQL.Simple qualified as Postgres
+import Database.PostgreSQL.Simple.Types qualified as Postgres
+import Database.Postgres.Temp qualified as TmpPg
+import FieldParser qualified as Field
+import Json qualified
+import Json.Enc (Enc)
+import Json.Enc qualified as Enc
+import Label
+import Network.HTTP.Simple qualified as Http
+import Network.HTTP.Types
+import PossehlAnalyticsPrelude
+import Postgres.Decoder qualified as Dec
+import Postgres.MonadPostgres
+import Pretty
+import System.Directory qualified as Dir
+import System.Directory qualified as Xdg
+import System.FilePath ((</>))
+import System.IO qualified as IO
+import UnliftIO
+
+data TransmissionRequest = TransmissionRequest
+  { method :: Text,
+    arguments :: Map Text Enc,
+    tag :: Maybe Int
+  }
+  deriving stock (Show)
+
+requestListAllTorrents =
+  TransmissionRequest
+    { method = "torrent-get",
+      arguments =
+        Map.fromList
+          [ ("fields", Enc.list Enc.text ["id", "name"])
+          ],
+      tag = Nothing
+    }
+
+data TransmissionResponse = TransmissionResponse
+  { result :: TransmissionResponseStatus,
+    arguments :: Map Text Json.Value,
+    tag :: Maybe Int
+  }
+  deriving stock (Show)
+
+data TransmissionResponseStatus
+  = TransmissionResponseSuccess
+  | TransmissionResponseFailure Text
+  deriving stock (Show)
+
+doTransmissionRequest ::
+  ( MonadIO m,
+    MonadTransmission m,
+    HasField "host" t1 Text,
+    HasField "port" t1 Text,
+    MonadThrow m
+  ) =>
+  t1 ->
+  TransmissionRequest ->
+  m TransmissionResponse
+doTransmissionRequest dat req = do
+  sessionId <- getTransmissionId
+  let httpReq =
+        [fmt|http://{dat.host}:{dat.port}/transmission/rpc|]
+          & Http.setRequestMethod "POST"
+          & Http.setRequestBodyLBS
+            ( Enc.encToBytesUtf8Lazy $
+                Enc.object
+                  ( [ ("method", req.method & Enc.text),
+                      ("arguments", Enc.map id req.arguments)
+                    ]
+                      <> (req.tag & maybe [] (\t -> [("tag", t & Enc.int)]))
+                  )
+            )
+          & (sessionId & maybe id (Http.setRequestHeader "X-Transmission-Session-Id" . (: [])))
+  resp <- Http.httpBS httpReq
+  -- Implement the CSRF protection thingy
+  case resp & Http.getResponseStatus & (.statusCode) of
+    409 -> do
+      tid <-
+        resp
+          & Http.getResponseHeader "X-Transmission-Session-Id"
+          & nonEmpty
+          & annotate [fmt|Missing "X-Transmission-Session-Id" header in 409 response: {showPretty resp}|]
+          & unwrapIOError
+          & liftIO
+          <&> NonEmpty.head
+      setTransmissionId tid
+      doTransmissionRequest dat req
+    200 ->
+      resp
+        & Http.getResponseBody
+        & Json.parseStrict
+          ( Json.mapError singleError $ do
+              result <-
+                Json.key "result" Json.asText <&> \case
+                  "success" -> TransmissionResponseSuccess
+                  err -> TransmissionResponseFailure err
+              arguments <-
+                Json.keyMay "arguments" Json.asObject
+                  <&> fromMaybe mempty
+                  <&> KeyMap.toMapText
+              tag <-
+                Json.keyMay
+                  "tag"
+                  (Field.jsonParser (Field.jsonNumber >>> Field.boundedScientificIntegral "tag too long"))
+              pure TransmissionResponse {..}
+          )
+        & first (Json.parseErrorTree "Cannot parse transmission RPC response")
+        & \case
+          Right a -> pure a
+          Left err -> appThrowTree err
+    _ -> liftIO $ unwrapIOError $ Left [fmt|Non-200 response: {showPretty resp}|]
+
+runAppWith :: AppT IO a -> IO (Either TmpPg.StartError a)
+runAppWith appT = withDb $ \db -> do
+  tools <- initMonadTools (label @"envvar" "WHATCD_RESOLVER_TOOLS")
+  let config = label @"logDatabaseQueries" LogDatabaseQueries
+  pgConnPool <-
+    Pool.createPool
+      (Postgres.connectPostgreSQL (db & TmpPg.toConnectionString))
+      Postgres.close
+      {- number of stripes -} 5
+      {- unusedResourceOpenTime -} 10
+      {- max resources per stripe -} 10
+  transmissionSessionId <- newEmptyMVar
+  runReaderT appT.unAppT Context {..}
+
+withDb :: (TmpPg.DB -> IO a) -> IO (Either TmpPg.StartError a)
+withDb act = do
+  dataDir <- Xdg.getXdgDirectory Xdg.XdgData "whatcd-resolver"
+  let databaseDir = dataDir </> "database"
+  initDbConfig <-
+    Dir.doesDirectoryExist databaseDir >>= \case
+      True -> pure TmpPg.Zlich
+      False -> do
+        putStderrLn [fmt|Database does not exist yet, creating in "{databaseDir}"|]
+        Dir.createDirectoryIfMissing True databaseDir
+        pure TmpPg.DontCare
+  let cfg =
+        mempty
+          { TmpPg.dataDirectory = TmpPg.Permanent (databaseDir),
+            TmpPg.initDbConfig
+          }
+  TmpPg.withConfig cfg $ \db -> do
+    -- print [fmt|data dir: {db & TmpPg.toDataDirectory}|]
+    -- print [fmt|conn string: {db & TmpPg.toConnectionString}|]
+    act db
+
+data Context = Context
+  { config :: Label "logDatabaseQueries" DatabaseLogging,
+    tools :: Tools,
+    pgConnPool :: Pool Postgres.Connection,
+    transmissionSessionId :: MVar ByteString
+  }
+
+newtype AppT m a = AppT {unAppT :: ReaderT Context m a}
+  deriving newtype (Functor, Applicative, Monad, MonadIO, MonadUnliftIO, MonadThrow)
+
+data AppException = AppException Text
+  deriving stock (Show)
+  deriving anyclass (Exception)
+
+appThrowTree :: MonadThrow m => ErrorTree -> m a
+appThrowTree exc = throwM $ AppException $ prettyErrorTree exc
+
+instance MonadIO m => MonadLogger (AppT m) where
+  monadLoggerLog loc src lvl msg = liftIO $ Logger.defaultOutput IO.stderr loc src lvl (Logger.toLogStr msg)
+
+instance Monad m => MonadTools (AppT m) where
+  getTools = AppT $ asks (.tools)
+
+class MonadTransmission m where
+  getTransmissionId :: m (Maybe ByteString)
+  setTransmissionId :: ByteString -> m ()
+
+instance (MonadIO m) => MonadTransmission (AppT m) where
+  getTransmissionId = AppT (asks (.transmissionSessionId)) >>= tryTakeMVar
+  setTransmissionId t = do
+    var <- AppT $ asks (.transmissionSessionId)
+    putMVar var t
+
+instance (MonadThrow m, MonadUnliftIO m) => MonadPostgres (AppT m) where
+  execute qry params = do
+    conf <- lift $ AppT (asks (.config))
+    logQueryIfEnabled conf qry (Left params)
+    pgExecute qry params
+  executeMany qry params = do
+    conf <- lift $ AppT (asks (.config))
+    logQueryIfEnabled conf qry (Right params)
+    pgExecuteMany qry params
+  executeManyReturning qry params = do
+    conf <- lift $ AppT (asks (.config))
+    logQueryIfEnabled conf qry (Right params)
+    pgExecuteManyReturning qry params
+
+  queryWith qry params decoder = do
+    conf <- lift $ AppT (asks (.config))
+    logQueryIfEnabled conf qry (Left params)
+    pgQueryWith qry params decoder
+
+  -- TODO: log these queries as well with `logQueryIfEnabled`, but test out whether it works with query_ and foldRows first.
+  queryWith_ = pgQueryWith_
+  foldRows = pgFold
+
+  runTransaction = runPGTransaction
+
+runPGTransaction :: MonadUnliftIO m => Transaction (AppT m) a -> AppT m a
+runPGTransaction (Transaction transaction) = do
+  pool <- AppT ask <&> (.pgConnPool)
+  withRunInIO $ \unliftIO ->
+    withPGTransaction pool $ \conn -> do
+      unliftIO $ runReaderT transaction conn
+
+-- | Perform a Postgres action within a transaction
+withPGTransaction ::
+  -- | Postgres connection pool to be used for the action
+  Pool Postgres.Connection ->
+  -- | DB-action to be performed
+  (Postgres.Connection -> IO a) ->
+  -- | Result of the DB-action
+  IO a
+withPGTransaction connPool f =
+  Pool.withResource
+    connPool
+    (\conn -> Postgres.withTransaction conn (f conn))
+
+-- | Log the postgres query depending on the setting of @config.debugInfo.logDatabaseQueries@.
+logQueryIfEnabled ::
+  ( Postgres.ToRow params,
+    MonadUnliftIO m,
+    MonadLogger m,
+    MonadTools m,
+    HasField "logDatabaseQueries" config DatabaseLogging
+  ) =>
+  config ->
+  Postgres.Query ->
+  Either params [params] ->
+  Transaction m ()
+logQueryIfEnabled config qry params = do
+  -- In case we have query logging enabled, we want to do that
+  let formattedQuery = case params of
+        Left p -> pgFormatQuery' qry p
+        Right ps -> pgFormatQueryMany' qry ps
+
+  let doLog errs =
+        errs
+          & nestedMultiError "Postgres query"
+          & prettyErrorTree
+          & logDebug
+          & lift
+  let addQuery = do
+        formattedQuery
+          <&> newError
+          <&> singleError
+  let addExplain = do
+        q <- formattedQuery
+        pgQueryWith_
+          ( "EXPLAIN "
+              <> (
+                   -- TODO: this is not nice, but the only way to get the `executeMany` form to work with this
+                   -- because we need the query with all elements already interpolated.
+                   Postgres.Query (q & textToBytesUtf8)
+                 )
+          )
+          (Dec.fromField @Text)
+          <&> Text.intercalate "\n"
+          <&> newError
+          <&> singleError
+
+  case config.logDatabaseQueries of
+    DontLogDatabaseQueries -> pure ()
+    LogDatabaseQueries -> do
+      aq <- addQuery
+      doLog (aq :| [])
+    LogDatabaseQueriesAndExplain -> do
+      aq <- addQuery
+      -- XXX: stuff like `CREATE SCHEMA` cannot be EXPLAINed, so we should catch exceptions here
+      -- and just ignore anything that errors (if it errors because of a problem with the query, it would have been caught by the query itself.
+      ex <- addExplain
+      doLog (nestedError "Query" aq :| [nestedError "Explain" ex])
+
+data DatabaseLogging
+  = DontLogDatabaseQueries
+  | LogDatabaseQueries
+  | LogDatabaseQueriesAndExplain