System.Log.FastLogger

This module provides a fast logging system which scales on multicore environments (i.e. +RTS -N<x>).

Creating a logger set

data LoggerSet

A set of loggers. The number of loggers is the capabilities of GHC RTS. You can specify it with "+RTS -N<x>". A buffer is prepared for each capability.

newFileLoggerSet :: BufSize -> FilePath -> IO LoggerSet

Creating a new LoggerSet using a file.

newStdoutLoggerSet :: BufSize -> IO LoggerSet

Creating a new LoggerSet using stdout.

newStderrLoggerSet :: BufSize -> IO LoggerSet

Creating a new LoggerSet using stderr.

newLoggerSet :: BufSize -> Maybe FilePath -> IO LoggerSet

Deprecated: Use newFileLoggerSet etc instead

Creating a new LoggerSet. If Nothing is specified to the second argument, stdout is used. Please note that the minimum BufSize is 1.

Buffer size

type BufSize = Int

The type for buffer size of each core.

defaultBufSize :: BufSize

The default buffer size (4,096 bytes).

Renewing and removing a logger set

renewLoggerSet :: LoggerSet -> IO ()

Renewing the internal file information in LoggerSet. This does nothing for stdout and stderr.

rmLoggerSet :: LoggerSet -> IO ()

Flushing the buffers, closing the internal file information and freeing the buffers.

Log messages

data LogStr

Log message builder. Use (<>) to append two LogStr in O(1).

Instances

IsString LogStr

Monoid LogStr

ToLogStr LogStr

class ToLogStr msg where

Methods

toLogStr :: msg -> LogStr

Instances

ToLogStr String

ToLogStr Text

ToLogStr Text

ToLogStr ByteString

ToLogStr ByteString

ToLogStr LogStr

fromLogStr :: LogStr -> ByteString

Converting LogStr to ByteString.

logStrLength :: LogStr -> Int

Obtaining the length of LogStr.

Writing a log message

pushLogStr :: LoggerSet -> LogStr -> IO ()

Writing a log message to the corresponding buffer. If the buffer becomes full, the log messages in the buffer are written to its corresponding file, stdout, or stderr.

Flushing buffered log messages

flushLogStr :: LoggerSet -> IO ()

Flushing log messages in buffers. This function must be called explicitly when the program is being terminated.

Note: Since version 2.1.6, this function does not need to be explicitly called, as every push includes an auto-debounced flush courtesy of the auto-update package.

File rotation

module System.Log.FastLogger.File