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module ActiveSupport::TaggedLogging

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.

Public Class Methods

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

  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

Public Instance Methods

flush() Show source 
# File activesupport/lib/active_support/tagged_logging.rb, line 108
def flush
  clear_tags!
  super if defined?(super)
end
Calls superclass method
tagged(*tags) { |self| ... } Show 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

© 2004–2020 David Heinemeier Hansson
Licensed under the MIT License.