Question

我不明白为什么hslogger在这段代码中调用infoM时没有写任何日志：

{-# LANGUAGE CPP #-}

-- hslogger
import System.Log.Logger         ( Priority(INFO, WARNING), addHandler
                                 , infoM, warningM, updateGlobalLogger
                                 )
import System.Log.Handler.Simple (fileHandler)

#define INF  

main :: IO ()
main = do
  let logger = "main"


#ifdef INF 

  let fileName   = "info.log"
  h1 <- fileHandler fileName INFO
  putStrLn "opened file1"
  updateGlobalLogger logger $ addHandler h1
  putStrLn "will write1"
  infoM logger "writing 1"
  putStrLn "did write1"

#else

  let fileName = "warn.log"
  h2 <- fileHandler fileName WARNING
  putStrLn "opened file2"
  updateGlobalLogger logger $ addHandler h2
  putStrLn "will write2"
  warningM logger "writing 2"
  putStrLn "did write2"

#endif

编译并运行此代码时，info.log为空。但是，如果我注释掉或删除#define INF，则warn.log包含“写入2”。这是为什么？

Answer 1

如果我没记错，hslogger中的默认日志级别为WARNING，如果您想查看INFO消息，则应将其设置为INFO。

updateGlobalLogger logger $ setLevel INFO

Answer 2

  updateGlobalLogger rootLoggerName (setLevel INFO)

为什么hslogger没有写一个INFO日志？

2 个答案: