Control.Logging

Quick example of how to use this module:

import Control.Logging

main = withStdoutLogging $ do
     log This is a log message!
     timedLog This is a timed log message! $ threadDelay 100000

Documentation

log :: MonadLogger m => Text -> m ()

Synonym for logInfoN. This module provides a MonadLogger instance for IO, so this function can be used directly in IO. The only requirement is that you must surround the body of your main function with a call to withStdoutLogging or withStderrLogging, to ensure that all logging buffers are properly flushed on exit.

log' :: (MonadLogger m, MonadIO m) => Text -> m ()

The apostrophe varients of the logging functions flush the log after each message.

warn :: MonadLogger m => Text -> m ()

warn' :: (MonadLogger m, MonadIO m) => Text -> m ()

debug :: MonadLogger m => Text -> m ()

debug' :: (MonadLogger m, MonadIO m) => Text -> m ()

errorL :: Text -> a

A logging variant of error which uses unsafePerformIO to output a log message before calling error.

errorL' :: Text -> a

traceL :: Text -> a -> a

traceL' :: Text -> a -> a

traceShowL :: Show a => a -> a1 -> a1

traceShowL' :: Show a => a -> a1 -> a1

timedLog :: (MonadLogger m, MonadBaseControl IO m, MonadIO m) => Text -> m () -> m ()

Output a logging message both before an action begins, and after it ends, reporting the total length of time. If an exception occurred, it is also reported.

timedLog' :: (MonadLogger m, MonadBaseControl IO m, MonadIO m) => Text -> m () -> m ()

timedLogEnd :: (MonadLogger m, MonadBaseControl IO m, MonadIO m) => Text -> m () -> m ()

Like timedLog, except that it does only logs when the action has completed or failed after it is done.

timedLogEnd' :: (MonadLogger m, MonadBaseControl IO m, MonadIO m) => Text -> m () -> m ()

timedDebug :: (MonadLogger m, MonadBaseControl IO m, MonadIO m) => Text -> m () -> m ()

A debug variant of timedLog.

timedDebug' :: (MonadLogger m, MonadBaseControl IO m, MonadIO m) => Text -> m () -> m ()

timedDebugEnd :: (MonadLogger m, MonadBaseControl IO m, MonadIO m) => Text -> m () -> m ()

timedDebugEnd' :: (MonadLogger m, MonadBaseControl IO m, MonadIO m) => Text -> m () -> m ()

withStdoutLogging :: (MonadBaseControl IO m, MonadIO m) => m a -> m a

This function, or withStderrLogging, must be wrapped around whatever region of your application intends to use logging. Typically it would be wrapped around the body of main.

withStderrLogging :: (MonadBaseControl IO m, MonadIO m) => m a -> m a

flushLog :: MonadIO m => m ()

setDebugLevel :: LogLevel -> IO ()

Set the verbosity level. Messages at our higher than this level are displayed. It defaults to LevelDebug.

setLogFormat :: String -> IO ()

Set the format used for log timestamps.