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#
#
# Nimrod's Runtime Library
# (c) Copyright 2014 Andreas Rumpf, Dominik Picheta
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
## This module implements a simple logger. It has been designed to be as simple
## as possible to avoid bloat, if this library does not fullfill your needs,
## write your own.
##
## Format strings support the following variables which must be prefixed with
## the dollar operator (``$``):
##
## ============ =======================
## Operator Output
## ============ =======================
## $date Current date
## $time Current time
## $app ``os.getAppFilename()``
## ============ =======================
##
##
## The following example demonstrates logging to three different handlers
## simultaneously:
##
## .. code-block:: nimrod
##
## var L = newConsoleLogger()
## var fL = newFileLogger("test.log", fmtStr = verboseFmtStr)
## var rL = newRollingFileLogger("rolling.log", fmtStr = verboseFmtStr)
## handlers.add(L)
## handlers.add(fL)
## handlers.add(rL)
## info("920410:52 accepted")
## warn("4 8 15 16 23 4-- Error")
## error("922044:16 SYSTEM FAILURE")
## fatal("SYSTEM FAILURE SYSTEM FAILURE")
import strutils, os, times
type
TLevel* = enum ## logging level
lvlAll, ## all levels active
lvlDebug, ## debug level (and any above) active
lvlInfo, ## info level (and any above) active
lvlWarn, ## warn level (and any above) active
lvlError, ## error level (and any above) active
lvlFatal, ## fatal level (and any above) active
lvlNone ## no levels active
const
LevelNames*: array [TLevel, string] = [
"DEBUG", "DEBUG", "INFO", "WARN", "ERROR", "FATAL", "NONE"
]
defaultFmtStr* = "" ## default string between log level and message per logger
verboseFmtStr* = "$date $time "
type
PLogger* = ref object of PObject ## 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.
PConsoleLogger* = ref object of PLogger ## logger that writes the messages to the
## console
PFileLogger* = ref object of PLogger ## logger that writes the messages to a file
f: TFile
PRollingFileLogger* = ref object of PFileLogger ## logger that writes the
## messages to a file and
## performs log rotation
maxLines: int # maximum number of lines
curLine : int
baseName: string # initial filename
baseMode: TFileMode # initial file mode
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*(logger: PLogger, level: TLevel,
frmt: string, args: varargs[string, `$`]) {.raises: [EBase], tags: [FTime, FWriteIO, FReadIO].} =
## Override this method in custom loggers. Default implementation does
## nothing.
discard
method log*(logger: PConsoleLogger, level: TLevel,
frmt: string, args: varargs[string, `$`]) =
## Logs to the console using ``logger`` only.
if level >= logger.levelThreshold:
writeln(stdout, LevelNames[level], " ", substituteLog(logger.fmtStr),
frmt % args)
method log*(logger: PFileLogger, level: TLevel,
frmt: string, args: varargs[string, `$`]) =
## Logs to a file using ``logger`` only.
if level >= logger.levelThreshold:
writeln(logger.f, LevelNames[level], " ",
substituteLog(logger.fmtStr), frmt % args)
proc defaultFilename*(): string =
## Returns the default filename for a logger.
var (path, name, ext) = splitFile(getAppFilename())
result = changeFileExt(path / name, "log")
proc newConsoleLogger*(levelThreshold = lvlAll, fmtStr = defaultFmtStr): PConsoleLogger =
## Creates a new console logger. This logger logs to the console.
new result
result.fmtStr = fmtStr
result.levelThreshold = levelThreshold
proc newFileLogger*(filename = defaultFilename(),
mode: TFileMode = fmAppend,
levelThreshold = lvlAll,
fmtStr = defaultFmtStr): PFileLogger =
## Creates a new file logger. This logger logs to a file.
new(result)
result.levelThreshold = levelThreshold
result.f = open(filename, mode)
result.fmtStr = fmtStr
# ------
proc countLogLines(logger: PRollingFileLogger): int =
result = 0
for line in logger.f.lines():
result.inc()
proc countFiles(filename: string): int =
# Example: file.log.1
result = 0
let (dir, name, ext) = splitFile(filename)
for kind, path in walkDir(dir):
if kind == pcFile:
let llfn = name & ext & ExtSep
if path.extractFilename.startsWith(llfn):
let numS = path.extractFilename[llfn.len .. -1]
try:
let num = parseInt(numS)
if num > result:
result = num
except EInvalidValue: discard
proc newRollingFileLogger*(filename = defaultFilename(),
mode: TFileMode = fmReadWrite,
levelThreshold = lvlAll,
fmtStr = defaultFmtStr,
maxLines = 1000): PRollingFileLogger =
## Creates a new rolling file logger. Once a file reaches ``maxLines`` lines
## a new log file will be started and the old will be renamed.
new(result)
result.levelThreshold = levelThreshold
result.fmtStr = defaultFmtStr
result.maxLines = maxLines
result.f = open(filename, mode)
result.curLine = 0
result.baseName = filename
result.baseMode = mode
result.logFiles = countFiles(filename)
if mode == fmAppend:
# We need to get a line count because we will be appending to the file.
result.curLine = countLogLines(result)
proc rotate(logger: PRollingFileLogger) =
let (dir, name, ext) = splitFile(logger.baseName)
for i in countdown(logger.logFiles, 0):
let srcSuff = if i != 0: ExtSep & $i else: ""
moveFile(dir / (name & ext & srcSuff),
dir / (name & ext & ExtSep & $(i+1)))
method log*(logger: PRollingFileLogger, level: TLevel,
frmt: string, args: varargs[string, `$`]) =
## Logs to a file using rolling ``logger`` only.
if level >= logger.levelThreshold:
if logger.curLine >= logger.maxLines:
logger.f.close()
rotate(logger)
logger.logFiles.inc
logger.curLine = 0
logger.f = open(logger.baseName, logger.baseMode)
writeln(logger.f, LevelNames[level], " ", frmt % args)
logger.curLine.inc
# --------
var
level* = lvlAll ## global log filter
handlers*: seq[PLogger] = @[] ## 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 to all registered handlers at the given level.
bind logLoop
bind `%`
bind logging.Level
if level >= logging.Level:
logLoop(level, frmt, args)
template debug*(frmt: string, args: varargs[string, `$`]) =
## Logs a debug message to all registered handlers.
log(lvlDebug, frmt, args)
template info*(frmt: string, args: varargs[string, `$`]) =
## Logs an info message to all registered handlers.
log(lvlInfo, frmt, args)
template warn*(frmt: string, args: varargs[string, `$`]) =
## Logs a warning message to all registered handlers.
log(lvlWarn, frmt, args)
template error*(frmt: string, args: varargs[string, `$`]) =
## Logs an error message to all registered handlers.
log(lvlError, frmt, args)
template fatal*(frmt: string, args: varargs[string, `$`]) =
## Logs a fatal error message to all registered handlers.
log(lvlFatal, frmt, args)
# --------------
when isMainModule:
var L = newConsoleLogger()
var fL = newFileLogger("test.log", fmtStr = verboseFmtStr)
var rL = newRollingFileLogger("rolling.log", fmtStr = verboseFmtStr)
handlers.add(L)
handlers.add(fL)
handlers.add(rL)
for i in 0 .. 25:
info("hello" & $i, [])
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