Wraps any standard Logger object to provide tagging capabilities.

May be called with a block:

logger = ActiveSupport::TaggedLogging.new(Logger.new(STDOUT))
logger.tagged('BCX') { logger.info 'Stuff' }                            # Logs "[BCX] Stuff"
logger.tagged('BCX', "Jason") { logger.info 'Stuff' }                   # Logs "[BCX] [Jason] Stuff"
logger.tagged('BCX') { logger.tagged('Jason') { logger.info 'Stuff' } } # Logs "[BCX] [Jason] Stuff"

If called without a block, a new logger will be returned with applied tags:

logger = ActiveSupport::TaggedLogging.new(Logger.new(STDOUT))
logger.tagged("BCX").info "Stuff"                 # Logs "[BCX] Stuff"
logger.tagged("BCX", "Jason").info "Stuff"        # Logs "[BCX] [Jason] Stuff"
logger.tagged("BCX").tagged("Jason").info "Stuff" # Logs "[BCX] [Jason] Stuff"

This is used by the default Rails.logger as configured by Railties to make it easy to stamp log lines with subdomains, request ids, and anything else to aid debugging of multi-user production applications.

Methods

Class Public methods

new(logger)

Source: 

# File activesupport/lib/active_support/tagged_logging.rb, line 81
def self.new(logger)
  logger = logger.clone

  if logger.formatter
    logger.formatter = logger.formatter.dup
  else
    # Ensure we set a default formatter so we aren't extending nil!
    logger.formatter = ActiveSupport::Logger::SimpleFormatter.new
  end

  logger.formatter.extend Formatter
  logger.extend(self)
end

Instance Public methods

flush()

Source: 

# File activesupport/lib/active_support/tagged_logging.rb, line 108
def flush
  clear_tags!
  super if defined?(super)
end

tagged(*tags)

Source: 

# File activesupport/lib/active_support/tagged_logging.rb, line 97
def tagged(*tags)
  if block_given?
    formatter.tagged(*tags) { yield self }
  else
    logger = ActiveSupport::TaggedLogging.new(self)
    logger.formatter.extend LocalTagStorage
    logger.push_tags(*formatter.current_tags, *tags)
    logger
  end
end