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Class: ActiveSupport::BroadcastLogger

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Instance Chain:
self, LoggerThreadSafeLevel, LoggerSilence
Inherits: Object
Defined in: activesupport/lib/active_support/broadcast_logger.rb

Overview

The Broadcast logger is a logger used to write messages to multiple ::IO. It is commonly used in development to display messages on STDOUT and also write them to a file (development.log). With the Broadcast logger, you can broadcast your logs to a unlimited number of sinks.

The BroadcastLogger acts as a standard logger and all methods you are used to are available. However, all the methods on this logger will propagate and be delegated to the other loggers that are part of the broadcast.

Broadcasting your logs.

stdout_logger = Logger.new(STDOUT)
file_logger   = Logger.new("development.log")
broadcast = BroadcastLogger.new(stdout_logger, file_logger)

broadcast.info("Hello world!") # Writes the log to STDOUT and the development.log file.

Add a logger to the broadcast.

stdout_logger = Logger.new(STDOUT)
broadcast = BroadcastLogger.new(stdout_logger)
file_logger   = Logger.new("development.log")
broadcast.broadcast_to(file_logger)

broadcast.info("Hello world!") # Writes the log to STDOUT and the development.log file.

Modifying the log level for all broadcasted loggers.

stdout_logger = Logger.new(STDOUT)
file_logger   = Logger.new("development.log")
broadcast = BroadcastLogger.new(stdout_logger, file_logger)

broadcast.level = Logger::FATAL # Modify the log level for the whole broadcast.

Stop broadcasting log to a sink.

stdout_logger = Logger.new(STDOUT)
file_logger   = Logger.new("development.log")
broadcast = BroadcastLogger.new(stdout_logger, file_logger)
broadcast.info("Hello world!") # Writes the log to STDOUT and the development.log file.

broadcast.stop_broadcasting_to(file_logger)
broadcast.info("Hello world!") # Writes the log *only* to STDOUT.

At least one sink has to be part of the broadcast. Otherwise, your logs will not be written anywhere. For instance:

broadcast = BroadcastLogger.new
broadcast.info("Hello world") # The log message will appear nowhere.

If you are adding a custom logger with custom methods to the broadcast, the BroadcastLogger will proxy them and return the raw value, or an array of raw values, depending on how many loggers in the broadcasts responded to the method:

class MyLogger < ::Logger
  def loggable?
    true
  end
end

logger = BroadcastLogger.new
logger.loggable? # => A NoMethodError exception is raised because no loggers in the broadcasts could respond.

logger.broadcast_to(MyLogger.new(STDOUT))
logger.loggable? # => true
logger.broadcast_to(MyLogger.new(STDOUT))
puts logger.broadcasts # => [MyLogger, MyLogger]
logger.loggable? # [true, true]

LoggerSilence - Attributes & Methods

Class Method Summary

Instance Attribute Summary

LoggerThreadSafeLevel - self

#local_level, #local_level=

Instance Method Summary

LoggerThreadSafeLevel - self

#level,
#log_at

Change the thread-local level for the duration of the given block.
#local_level_key

LoggerSilence - Included

#silence

Silences the logger for the duration of the block.

Constructor Details

.new(*loggers) ⇒ BroadcastLogger

[ GitHub ] 

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 82



def initialize(*loggers)
  @broadcasts = []
  @progname = "Broadcast"

  broadcast_to(*loggers)
end


  







Dynamic Method Handling

  

    This class handles dynamic methods through the method_missing method




  

    #method_missing(name)   (private)
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 235



def method_missing(name, ...)
  loggers = @broadcasts.select { |logger| logger.respond_to?(name) }

  if loggers.none?
    super
  elsif loggers.one?
    loggers.first.send(name, ...)
  else
    loggers.map { |logger| logger.send(name, ...) }
  end
end


  







Class Attribute Details



  

    .silencer   (rw)
    Also known as: #silencer
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/logger_silence.rb', line 12



cattr_accessor :silencer, default: true


  







Instance Attribute Details



  

    #broadcasts   (readonly)
  



  

    

Returns all the logger that are part of this broadcast.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 78



attr_reader :broadcasts


  








  

    #debug?  ⇒ Boolean  (readonly)
  



  

    

True if the log level allows entries with severity Logger::DEBUG to be written to at least one broadcast. False otherwise.


  





  


  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 168



def debug?
  @broadcasts.any? { |logger| logger.debug? }
end


  








  

    #error?  ⇒ Boolean  (readonly)
  



  

    

True if the log level allows entries with severity Logger::ERROR to be written to at least one broadcast. False otherwise.


  





  


  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 201



def error?
  @broadcasts.any? { |logger| logger.error? }
end


  








  

    #fatal?  ⇒ Boolean  (readonly)
  



  

    

True if the log level allows entries with severity Logger::FATAL to be written to at least one broadcast. False otherwise.


  





  


  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 212



def fatal?
  @broadcasts.any? { |logger| logger.fatal? }
end


  








  

    #formatter   (rw)
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 79



attr_reader :formatter


  








  

    #formatter=(formatter)   (rw)
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 145



def formatter=(formatter)
  dispatch { |logger| logger.formatter = formatter }

  @formatter = formatter
end


  








  

    #info?  ⇒ Boolean  (readonly)
  



  

    

True if the log level allows entries with severity Logger::INFO to be written to at least one broadcast. False otherwise.


  





  


  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 179



def info?
  @broadcasts.any? { |logger| logger.info? }
end


  








  

    #level   (rw)
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 108



def level
  @broadcasts.map(&:level).min
end


  








  

    #level=(level)   (rw)
    Also known as: #sev_threshold=
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 151



def level=(level)
  dispatch { |logger| logger.level = level }
end


  








  

    #local_level=(level)   (writeonly)
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 156



def local_level=(level)
  dispatch do |logger|
    logger.local_level = level if logger.respond_to?(:local_level=)
  end
end


  








  

    #progname   (rw)
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 80



attr_accessor :progname


  








  

    #silencer   (rw)
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/logger_silence.rb', line 12



cattr_accessor :silencer, default: true


  








  

    #warn?  ⇒ Boolean  (readonly)
  



  

    

True if the log level allows entries with severity Logger::WARN to be written to at least one broadcast. False otherwise.


  





  


  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 190



def warn?
  @broadcasts.any? { |logger| logger.warn? }
end


  







Instance Method Details



  

    #<<(message)  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 112



def <<(message)
  dispatch { |logger| logger.<<(message) }
end


  








  

    #add  
    Also known as: #log
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 116



def add(...)
  dispatch { |logger| logger.add(...) }
end


  








  

    #broadcast_to(*loggers)  
  



  

    

Add logger(s) to the broadcast.



broadcast_logger = ActiveSupport::BroadcastLogger.new
broadcast_logger.broadcast_to(Logger.new(STDOUT), Logger.new(STDERR))


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 93



def broadcast_to(*loggers)
  @broadcasts.concat(loggers)
end


  








  

    #close  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 162



def close
  dispatch { |logger| logger.close }
end


  








  

    #debug   (readonly)
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 121



def debug(...)
  dispatch { |logger| logger.debug(...) }
end


  








  

    #debug!  
  



  

    

Sets the log level to Logger::DEBUG for the whole broadcast.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 173



def debug!
  dispatch { |logger| logger.debug! }
end


  








  

    #dispatch(&block)   (private)
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 230



def dispatch(&block)
  @broadcasts.each { |logger| block.call(logger) }
  true
end


  








  

    #error   (readonly)
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 133



def error(...)
  dispatch { |logger| logger.error(...) }
end


  








  

    #error!  
  



  

    

Sets the log level to Logger::ERROR for the whole broadcast.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 206



def error!
  dispatch { |logger| logger.error! }
end


  








  

    #fatal   (readonly)
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 137



def fatal(...)
  dispatch { |logger| logger.fatal(...) }
end


  








  

    #fatal!  
  



  

    

Sets the log level to Logger::FATAL for the whole broadcast.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 217



def fatal!
  dispatch { |logger| logger.fatal! }
end


  








  

    #info   (readonly)
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 125



def info(...)
  dispatch { |logger| logger.info(...) }
end


  








  

    #info!  
  



  

    

Sets the log level to Logger::INFO for the whole broadcast.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 184



def info!
  dispatch { |logger| logger.info! }
end


  








  

    #initialize_copy(other)  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 221



def initialize_copy(other)
  @broadcasts = []
  @progname = other.progname.dup
  @formatter = other.formatter.dup

  broadcast_to(*other.broadcasts.map(&:dup))
end


  








  

    #log  
  



  

    

Alias for #add.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 119



alias_method :log, :add


  








  

    #respond_to_missing?(method, include_all)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 247



def respond_to_missing?(method, include_all)
  @broadcasts.any? { |logger| logger.respond_to?(method, include_all) }
end


  








  

    #stop_broadcasting_to(logger)  
  



  

    

Remove a logger from the broadcast. When a logger is removed, messages sent to the broadcast will no longer be written to its sink.



sink = Logger.new(STDOUT)
broadcast_logger = ActiveSupport::BroadcastLogger.new

broadcast_logger.stop_broadcasting_to(sink)


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 104



def stop_broadcasting_to(logger)
  @broadcasts.delete(logger)
end


  








  

    #unknown  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 141



def unknown(...)
  dispatch { |logger| logger.unknown(...) }
end


  








  

    #warn   (readonly)
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 129



def warn(...)
  dispatch { |logger| logger.warn(...) }
end


  








  

    #warn!  
  



  

    

Sets the log level to Logger::WARN for the whole broadcast.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/broadcast_logger.rb', line 195



def warn!
  dispatch { |logger| logger.warn! }
end