Change the default logger to print to stderr

Author: pepeiborra

ghcide/src/Development/IDE/Main.hs

@@ -16,7 +16,8 @@ import Data.List.Extra (
  )
 import Data.Maybe (catMaybes, fromMaybe, isJust)
 import qualified Data.Text as T
-import Development.IDE (Action, Rules, noLogging)
+import qualified Data.Text.IO as T
+import Development.IDE (Action, Rules, Priority)
 import Development.IDE.Core.Debouncer (newAsyncDebouncer)
 import Development.IDE.Core.FileStore (makeVFSHandle)
 import Development.IDE.Core.OfInterest (
@@ -49,7 +50,6 @@ import Development.IDE.Plugin (
 import Development.IDE.Plugin.HLS (asGhcIdePlugin)
 import Development.IDE.Session (SessionLoadingOptions, loadSessionWithOptions, setInitialDynFlags, getHieDbLoc, runWithDb)
 import Development.IDE.Types.Location (toNormalizedFilePath')
-import Development.IDE.Types.Logger (Logger)
 import Development.IDE.Types.Options (
     IdeGhcSession,
     IdeOptions (optCheckParents, optCheckProject, optReportProgress),
@@ -66,10 +66,11 @@ import qualified Language.LSP.Server as LSP
 import qualified System.Directory.Extra as IO
 import System.Exit (ExitCode (ExitFailure), exitWith)
 import System.FilePath (takeExtension, takeFileName)
-import System.IO (hPutStrLn, hSetEncoding, stderr, stdout, utf8)
+import System.IO (hSetBuffering, hPutStrLn, hSetEncoding, stderr, stdout, utf8, BufferMode (LineBuffering))
 import System.Time.Extra (offsetTime, showDuration)
 import Text.Printf (printf)
 import qualified Development.IDE.Plugin.HLS.GhcIde as Ghcide
+import Development.IDE.Types.Logger (Logger(Logger))
 
 data Arguments = Arguments
     { argsOTMemoryProfiling :: Bool
@@ -89,7 +90,7 @@ instance Default Arguments where
     def = Arguments
         { argsOTMemoryProfiling = False
         , argFiles = Nothing
-        , argsLogger = noLogging
+        , argsLogger = Logger stderrLogger
         , argsRules = mainRule >> action kick
         , argsGhcidePlugin = mempty
         , argsHlsPlugins = pluginDescToIdePlugins Ghcide.descriptors
@@ -100,9 +101,15 @@ instance Default Arguments where
         , argsGetHieDbLoc = getHieDbLoc
         }
 
+-- | Cheap stderr logger that relies on LineBuffering
+stderrLogger :: Priority -> T.Text -> IO ()
+stderrLogger p m =
+    T.hPutStrLn stderr $ "[" <> T.pack(show p) <> "] " <> m
+
 defaultMain :: Arguments -> IO ()
 defaultMain Arguments{..} = do
     pid <- T.pack . show <$> getProcessID
+    hSetBuffering stderr LineBuffering
 
     let hlsPlugin = asGhcIdePlugin argsDefaultHlsConfig argsHlsPlugins
         hlsCommands = allLspCmdIds' pid argsHlsPlugins