IOException of type ResourceBusy (openFile: resource busy (file is locked))

[YoEight]

Greetings.

I have that issue as soon as my code tries to write something to a file (It works when I use LogStdout for instance). The file I use doesn't exist before running my program. It's created properly by the library but it's empty (and got the error mentioned in the title).

OS: OSX Sierra
Library version: 2.4.10
GHC: 8.0.2
GHC OPTIONS: -threaded -rtsopts -with-rtsopts=-N

Here's how I use the code (with logMsg function):

--------------------------------------------------------------------------------
data LogManager =
  LogManager { logCallback :: TimedFastLogger
             , logLevel    :: LogLevel
             , _cleanUp    :: IO ()
             }

--------------------------------------------------------------------------------
data Logger =
  Logger { loggerName      :: Text
         , _loggerCallback :: TimedFastLogger
         , _loggerLevel    :: LogLevel
         }

--------------------------------------------------------------------------------
data LogLevel
  = Debug
  | Info
  | Warn
  | Error
  | Fatal
  deriving (Eq, Ord, Enum, Bounded)

--------------------------------------------------------------------------------
newLogManager :: LoggerSettings -> IO LogManager
newLogManager setts = do
  cache         <- newTimeCache simpleTimeFormat'
  (callback, cleanup) <- newTimedFastLogger cache (loggerType setts)
  return (LogManager callback (loggerLevel setts) cleanup)

--------------------------------------------------------------------------------
closeLogManager :: LogManager -> IO ()
closeLogManager LogManager{..} = _cleanUp

--------------------------------------------------------------------------------
getLogger :: Text -> LogManager -> Logger
getLogger name mgr =
  Logger { loggerName      = name
         , _loggerCallback = logCallback mgr
         , _loggerLevel    = logLevel mgr
         }

--------------------------------------------------------------------------------
logMsg :: MonadIO m => Logger -> LogLevel -> Text -> m ()
logMsg Logger{..} lvl msg
  | lvl < _loggerLevel = return ()
  | otherwise = liftIO $
    _loggerCallback $ \t ->
      toLogStr ("["`mappend` t `mappend`"]") `mappend` " eventstore "
                               `mappend` toLogStr (logLvlTxt lvl)
                               `mappend` toLogStr ("[" `mappend` loggerName `mappend` "] ")
                               `mappend` toLogStr msg
                               `mappend` "\n"

Thanks for your time.

[YoEight]

I also tried on Ubuntu 16.04.2 64 bits and got the exact same error. However this time, the file wasn't empty and had all the expected logs message in it.

[kazu-yamamoto]

It seems to me that other part of your program opens the log file. The base library prohibits to open a file two or more times.

[YoEight]

@kazu-yamamoto It turns out my testing library was running my test group in parallel hence the reason you mentioned. Thanks for your help and sorry for the noise.