Module: ActiveSupport::TaggedLogging

Relationships & Source Files
Namespace Children
Modules: `Formatter`, `LocalTagStorage`
Classes: `TagStack`
Defined in:	activesupport/lib/active_support/tagged_logging.rb

Overview

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") { |tagged_logger| tagged_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.

Class Method Summary

.logger(*args, **kwargs)

Returns an Logger that has already been wrapped with tagged logging concern.
.new(logger)
.ractor_logger(*args, **kwargs) Internal use only

Returns a logger that can be used from Ractors.

Instance Attribute Summary

#pop_tags readonly
#push_tags readonly

Class Method Details

.logger(*args, **kwargs)

Returns an Logger that has already been wrapped with tagged logging concern.

[ GitHub ]

# File 'activesupport/lib/active_support/tagged_logging.rb', line 122


def self.logger(*args, **kwargs)
  new ActiveSupport::Logger.new(*args, **kwargs)
end

.new(logger)

[ GitHub ]

# File 'activesupport/lib/active_support/tagged_logging.rb', line 135


def self.new(logger)
  logger = logger.clone

  if logger.formatter
    logger.formatter = logger.formatter.clone

    # Workaround for https://bugs.ruby-lang.org/issues/20250
    # Can be removed when Ruby 3.4 is the least supported version.
    logger.formatter.object_id if logger.formatter.is_a?(Proc)
  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

.ractor_logger(*args, **kwargs)

This method is for internal use only.

Returns a logger that can be used from Ractors. Accepts the same arguments as Logger.new. The returned logger is an Ractors::Logger (a ::Logger subclass whose device proxies writes to a background Writer) wrapped with tagged logging, so it can be made shareable and used from any Ractor.

[ GitHub ]

# File 'activesupport/lib/active_support/tagged_logging.rb', line 131


def self.ractor_logger(*args, **kwargs) # :nodoc:
  new(ActiveSupport::Ractors::Logger.new(*args, **kwargs))
end

Instance Attribute Details

#pop_tags (readonly)

[ GitHub ]

# File 'activesupport/lib/active_support/tagged_logging.rb', line 153


delegate :push_tags, :pop_tags, :clear_tags!, to: :formatter

#push_tags (readonly)

[ GitHub ]

# File 'activesupport/lib/active_support/tagged_logging.rb', line 153


delegate :push_tags, :pop_tags, :clear_tags!, to: :formatter

Instance Method Details

#clear_tags!

[ GitHub ]

# File 'activesupport/lib/active_support/tagged_logging.rb', line 153


delegate :push_tags, :pop_tags, :clear_tags!, to: :formatter

#flush

[ GitHub ]

# File 'activesupport/lib/active_support/tagged_logging.rb', line 166


def flush
  clear_tags!
  super if defined?(super)
end

#tagged(*tags)

[ GitHub ]

# File 'activesupport/lib/active_support/tagged_logging.rb', line 155


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