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#
#
# Nimrod's Runtime Library
# (c) Copyright 2012 Andreas Rumpf
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
## This module implements a simple logger. It is based on the following design:
## * Runtime log formating is a bug: Sooner or later every log file is parsed.
## * Keep it simple: If this library does not fullfill your needs, write your
## own. Trying to support every logging feature just leads to bloat.
##
## Format is::
##
## DEBUG|INFO|... (2009-11-02 00:00:00)? (Component: )? Message
##
##
import strutils, os, times
type
TLevel* = enum ## logging level
lvlAll, ## all levels active
lvlDebug, ## debug level (and any above) active
lvlInfo, ## info level (and any above) active
lvlWarn, ## warn level (and any above) active
lvlError, ## error level (and any above) active
lvlFatal, ## fatal level (and any above) active
lvlNone
const
LevelNames*: array [TLevel, string] = [
"DEBUG", "DEBUG", "INFO", "WARN", "ERROR", "FATAL", "NONE"
]
defaultFmtStr = "" ## default string between log level and message per logger
verboseFmtStr = "$date $time "
type
TLogger* = object of TObject ## abstract logger; the base type of all loggers
levelThreshold*: TLevel ## only messages of level >= levelThreshold
## should be processed
fmtStr: string ## = defaultFmtStr by default, see substituteLog for $date etc.
TConsoleLogger* = object of TLogger ## logger that writes the messages to the
## console
TFileLogger* = object of TLogger ## logger that writes the messages to a file
f: TFile
# TODO: implement rolling log, will produce filename.1, filename.2 etc.
TRollingFileLogger* = object of TFileLogger ## logger that writes the
## message to a file
maxLines: int # maximum number of lines
curLine : int
baseName: string # initial filename
logFiles: int # how many log files already created, e.g. basename.1, basename.2...
proc substituteLog*(frmt: string): string =
## converts $date to the current date
## converts $time to the current time
## converts $app to getAppFilename()
## converts
result = newStringOfCap(frmt.len + 20)
var i = 0
while i < frmt.len:
if frmt[i] != '$':
result.add(frmt[i])
inc(i)
else:
inc(i)
var v = ""
var app = getAppFilename()
while frmt[i] in IdentChars:
v.add(toLower(frmt[i]))
inc(i)
case v
of "date": result.add(getDateStr())
of "time": result.add(getClockStr())
of "app": result.add(app)
of "appdir": result.add(app.splitFile.dir)
of "appname": result.add(app.splitFile.name)
method log*(L: ref TLogger, level: TLevel,
frmt: string, args: varargs[string, `$`]) =
## override this method in custom loggers. Default implementation does
## nothing.
nil
method log*(L: ref TConsoleLogger, level: TLevel,
frmt: string, args: varargs[string, `$`]) =
Writeln(stdout, LevelNames[level], " ", substituteLog(L.fmtStr), frmt % args)
method log*(L: ref TFileLogger, level: TLevel,
frmt: string, args: varargs[string, `$`]) =
Writeln(L.f, LevelNames[level], " ", substituteLog(L.fmtStr), frmt % args)
proc defaultFilename*(): string =
## returns the default filename for a logger
var (path, name, ext) = splitFile(getAppFilename())
result = changeFileExt(path / name & "_" & getDateStr(), "log")
proc newConsoleLogger*(levelThreshold = lvlAll) : ref TConsoleLogger =
new result
result.fmtStr = defaultFmtStr
result.levelThreshold = levelThreshold
proc newFileLogger*(filename = defaultFilename(),
mode: TFileMode = fmAppend,
levelThreshold = lvlAll): ref TFileLogger =
new(result)
result.levelThreshold = levelThreshold
result.f = open(filename, mode)
result.fmtStr = defaultFmtStr
# ------
proc readLogLines(logger : ref TRollingFileLogger) = nil
#f.readLine # TODO read all lines, update curLine
proc newRollingFileLogger*(filename = defaultFilename(),
mode: TFileMode = fmReadWrite,
levelThreshold = lvlAll,
maxLines = 1000): ref TRollingFileLogger =
new(result)
result.levelThreshold = levelThreshold
result.fmtStr = defaultFmtStr
result.maxLines = maxLines
result.f = open(filename, mode)
result.curLine = 0
# TODO count all number files
# count lines in existing filename file
# if >= maxLines then rename to next numbered file and create new file
#if mode in {fmReadWrite, fmReadWriteExisting}:
# readLogLines(result)
method log*(L: ref TRollingFileLogger, level: TLevel,
frmt: string, args: varargs[string, `$`]) =
# TODO
# if more than maxlines, then set cursor to zero
Writeln(L.f, LevelNames[level], " ", frmt % args)
# --------
var
level* = lvlAll ## global log filter
handlers*: seq[ref TLogger] = @[] ## handlers with their own log levels
proc logLoop(level: TLevel, frmt: string, args: varargs[string, `$`]) =
for logger in items(handlers):
if level >= logger.levelThreshold:
log(logger, level, frmt, args)
template log*(level: TLevel, frmt: string, args: varargs[string, `$`]) =
## logs a message of the given level
bind logLoop
bind `%`
bind logging.Level
if level >= logging.Level:
logLoop(level, frmt, args)
template debug*(frmt: string, args: varargs[string, `$`]) =
## logs a debug message
log(lvlDebug, frmt, args)
template info*(frmt: string, args: varargs[string, `$`]) =
## logs an info message
log(lvlInfo, frmt, args)
template warn*(frmt: string, args: varargs[string, `$`]) =
## logs a warning message
log(lvlWarn, frmt, args)
template error*(frmt: string, args: varargs[string, `$`]) =
## logs an error message
log(lvlError, frmt, args)
template fatal*(frmt: string, args: varargs[string, `$`]) =
## logs a fatal error message
log(lvlFatal, frmt, args)
# --------------
when isMainModule:
var L = newConsoleLogger()
var fL = newFileLogger("test.log")
fL.fmtStr = verboseFmtStr
handlers.add(L)
handlers.add(fL)
info("hello", [])
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