class Logger::Application

Description¶ ↑

Application — Add logging support to your application.

Usage¶ ↑

Define your application class as a sub-class of this class.
Override the run method in your class to do many things.
Instantiate it and invoke start.

Example¶ ↑

class FooApp < Application
  def initialize(foo_app, application_specific, arguments)
    super('FooApp') # Name of the application.
  end

  def run
    ...
    log(WARN, 'warning', 'my_method1')
    ...
    @log.error('my_method2') { 'Error!' }
    ...
  end
end

status = FooApp.new(....).start

Attributes

appname[R]

Name of the application given at initialize.

Public Class Methods

new(appname = '') click to toggle source

Args¶ ↑

appname: Name of the application.

Description¶ ↑

Create an instance. Log device is STDERR by default. This can be changed with set_log.

# File lib/logger.rb, line 728
def initialize(appname = nil)
  @appname = appname
  @log = Logger.new(STDERR)
  @log.progname = @appname
  @level = @log.level
end

Public Instance Methods

level=(level) click to toggle source

Set the logging threshold, just like Logger#level=.

# File lib/logger.rb, line 783
def level=(level)
  @level = level
  @log.level = @level
end

log(severity, message = nil, &block) click to toggle source

See Logger#add. This application's appname is used.

# File lib/logger.rb, line 791
def log(severity, message = nil, &block)
  @log.add(severity, message, @appname, &block) if @log
end

log=(logdev) click to toggle source

# File lib/logger.rb, line 776
def log=(logdev)
  set_log(logdev)
end

logger() click to toggle source

Logger for this application. See the class Logger for an explanation.

# File lib/logger.rb, line 752
def logger
  @log
end

logger=(logger) click to toggle source

Sets the logger for this application. See the class Logger for an explanation.

# File lib/logger.rb, line 760
def logger=(logger)
  @log = logger
  @log.progname = @appname
  @log.level = @level
end

set_log(logdev, shift_age = 0, shift_size = 1024000) click to toggle source

Sets the log device for this application. See Logger.new for an explanation of the arguments.

# File lib/logger.rb, line 770
def set_log(logdev, shift_age = 0, shift_size = 1024000)
  @log = Logger.new(logdev, shift_age, shift_size)
  @log.progname = @appname
  @log.level = @level
end

start() click to toggle source

Start the application. Return the status code.

# File lib/logger.rb, line 738
def start
  status = -1
  begin
    log(INFO, "Start of #{ @appname }.")
    status = run
  rescue
    log(FATAL, "Detected an exception. Stopping ... #{$!} (#{$!.class})\n" << $@.join("\n"))
  ensure
    log(INFO, "End of #{ @appname }. (status: #{ status.to_s })")
  end
  status
end

Private Instance Methods

run() click to toggle source

# File lib/logger.rb, line 797
def run
  # TODO: should be an NotImplementedError
  raise RuntimeError.new('Method run must be defined in the derived class.')
end