Class: Logger

Classes and Modules

Module Logger::Severity
Class Logger::Application
Class Logger::Error
Class Logger::Formatter
Class Logger::LogDevice
Class Logger::ShiftingError

Constants

VERSION	=	"1.2.6"
ProgName	=	"#{$1}/#{$2}"
SEV_LABEL	=	%w(DEBUG INFO WARN ERROR FATAL ANY)	Severity label for logging. (max 5 char)

External Aliases

level	->	sev_threshold
level=	->	sev_threshold=

Attributes

formatter	[RW]	Logging formatter. formattercall is invoked with 4 arguments; severity, time, progname and msg for each log. Bear in mind that time is a Time and msg is an Object that user passed and it could not be a String. It is expected to return a logdevwrite-able Object. Default formatter is used when no formatter is set.
level	[RW]	Logging severity threshold (e.g. `Logger::INFO`).
progname	[RW]	Logging program name.

Public Class methods

new(logdev, shift_age = 0, shift_size = 1048576)

Synopsis

  Logger.new(name, shift_age = 7, shift_size = 1048576)
  Logger.new(name, shift_age = 'weekly')

Args

`logdev`:	The log device. This is a filename (String) or IO object (typically `STDOUT`, `STDERR`, or an open file).
`shift_age`:	Number of old log files to keep, or frequency of rotation (`daily`, `weekly` or `monthly`).
`shift_size`:	Maximum logfile size (only applies when `shift_age` is a number).

Description

Create an instance.

[Source]

     # File lib/logger.rb, line 265
265:   def initialize(logdev, shift_age = 0, shift_size = 1048576)
266:     @progname = nil
267:     @level = DEBUG
268:     @default_formatter = Formatter.new
269:     @formatter = nil
270:     @logdev = nil
271:     if logdev
272:       @logdev = LogDevice.new(logdev, :shift_age => shift_age,
273:         :shift_size => shift_size)
274:     end
275:   end

Public Instance methods

<<(msg)

Dump given message to the log device without any formatting. If no log device exists, return nil.

[Source]

     # File lib/logger.rb, line 345
345:   def <<(msg)
346:     unless @logdev.nil?
347:       @logdev.write(msg)
348:     end
349:   end

add(severity, message = nil, progname = nil) {|| ...}

Synopsis

  Logger#add(severity, message = nil, progname = nil) { ... }

Args

`severity`:	Severity. Constants are defined in Logger namespace: `DEBUG`, `INFO`, `WARN`, `ERROR`, `FATAL`, or `UNKNOWN`.
`message`:	The log message. A String or Exception.
`progname`:	Program name string. Can be omitted. Treated as a message if no `message` and `block` are given.
`block`:	Can be omitted. Called to get a message string if `message` is nil.

Return

true if successful, false otherwise.

When the given severity is not high enough (for this particular logger), log no message, and return true.

Description

Log a message if the given severity is high enough. This is the generic logging method. Users will be more inclined to use debug, info, warn, error, and fatal.

Message format: message can be any object, but it has to be converted to a String in order to log it. Generally, inspect is used if the given object is not a String. A special case is an Exception object, which will be printed in detail, including message, class, and backtrace. See msg2str for the implementation if required.

Bugs

Logfile is not locked.
Append open does not need to lock file.
But on the OS which supports multi I/O, records possibly be mixed.

[Source]

     # File lib/logger.rb, line 321
321:   def add(severity, message = nil, progname = nil, &block)
322:     severity ||= UNKNOWN
323:     if @logdev.nil? or severity < @level
324:       return true
325:     end
326:     progname ||= @progname
327:     if message.nil?
328:       if block_given?
329:         message = yield
330:       else
331:         message = progname
332:         progname = @progname
333:       end
334:     end
335:     @logdev.write(
336:       format_message(format_severity(severity), Time.now, progname, message))
337:     true
338:   end

close()

Close the logging device.

[Source]

     # File lib/logger.rb, line 426
426:   def close
427:     @logdev.close if @logdev
428:   end

datetime_format()

[Source]

     # File lib/logger.rb, line 210
210:   def datetime_format
211:     @default_formatter.datetime_format
212:   end

datetime_format=(datetime_format)

Logging date-time format (string passed to strftime).

[Source]

     # File lib/logger.rb, line 206
206:   def datetime_format=(datetime_format)
207:     @default_formatter.datetime_format = datetime_format
208:   end

debug(progname = nil, &block)

Log a DEBUG message.

See info for more information.

[Source]

     # File lib/logger.rb, line 356
356:   def debug(progname = nil, &block)
357:     add(DEBUG, nil, progname, &block)
358:   end

debug?()

Returns true iff the current severity level allows for the printing of DEBUG messages.

[Source]

     # File lib/logger.rb, line 226
226:   def debug?; @level <= DEBUG; end

error(progname = nil, &block)

Log an ERROR message.

See info for more information.

[Source]

     # File lib/logger.rb, line 400
400:   def error(progname = nil, &block)
401:     add(ERROR, nil, progname, &block)
402:   end

error?()

Returns true iff the current severity level allows for the printing of ERROR messages.

[Source]

     # File lib/logger.rb, line 238
238:   def error?; @level <= ERROR; end

fatal(progname = nil, &block)

Log a FATAL message.

See info for more information.

[Source]

     # File lib/logger.rb, line 409
409:   def fatal(progname = nil, &block)
410:     add(FATAL, nil, progname, &block)
411:   end

fatal?()

Returns true iff the current severity level allows for the printing of FATAL messages.

[Source]

     # File lib/logger.rb, line 242
242:   def fatal?; @level <= FATAL; end

info(progname = nil, &block)

Log an INFO message.

The message can come either from the progname argument or the block. If both are provided, then the block is used as the message, and progname is used as the program name.

Examples

  logger.info("MainApp") { "Received connection from #{ip}" }
  # ...
  logger.info "Waiting for input from user"
  # ...
  logger.info { "User typed #{input}" }

You‘ll probably stick to the second form above, unless you want to provide a program name (which you can do with Logger#progname= as well).

Return

See add.

[Source]

     # File lib/logger.rb, line 382
382:   def info(progname = nil, &block)
383:     add(INFO, nil, progname, &block)
384:   end

info?()

Returns true iff the current severity level allows for the printing of INFO messages.

[Source]

     # File lib/logger.rb, line 230
230:   def info?; @level <= INFO; end

log(severity, message = nil, progname = nil, &block)

Alias for add

unknown(progname = nil, &block)

Log an UNKNOWN message. This will be printed no matter what the logger level.

See info for more information.

[Source]

     # File lib/logger.rb, line 419
419:   def unknown(progname = nil, &block)
420:     add(UNKNOWN, nil, progname, &block)
421:   end

warn(progname = nil, &block)

Log a WARN message.

See info for more information.

[Source]

     # File lib/logger.rb, line 391
391:   def warn(progname = nil, &block)
392:     add(WARN, nil, progname, &block)
393:   end

warn?()

Returns true iff the current severity level allows for the printing of WARN messages.

[Source]

     # File lib/logger.rb, line 234
234:   def warn?; @level <= WARN; end

Private Instance methods

format_message(severity, datetime, progname, msg)

[Source]

     # File lib/logger.rb, line 439
439:   def format_message(severity, datetime, progname, msg)
440:     (@formatter || @default_formatter).call(severity, datetime, progname, msg)
441:   end

format_severity(severity)

[Source]

     # File lib/logger.rb, line 435
435:   def format_severity(severity)
436:     SEV_LABEL[severity] || 'ANY'
437:   end

Methods

Included Modules

Classes and Modules

Constants

External Aliases

Attributes

Public Class methods

Synopsis

Args

Description

Public Instance methods

Synopsis

Args

Return

Description

Bugs

Examples

Return

Private Instance methods