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 ByteString

ToLogStr ByteString

ToLogStr Text

ToLogStr Text

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.

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

Same as pushLogStr but also appends a newline.

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. Since version 2.2.2, this function can be used to force flushing outside of the debounced flush calls.

File rotation

module System.Log.FastLogger.File