Active Support Broadcast Logger

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 β€˜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]

Methods

Included Modules

Attributes

[R] broadcasts

Returns all the logger that are part of this broadcast.
[RW] progname

Class Public methods

new(*loggers)

πŸ“ Source code 
# File activesupport/lib/active_support/broadcast_logger.rb, line 81
    def initialize(*loggers)
      @broadcasts = []
      @progname = "Broadcast"

      broadcast_to(*loggers)
    end
πŸ”Ž See on GitHub

Instance Public methods

broadcast_to(*loggers)

Add logger(s) to the broadcast.

broadcast_logger = ActiveSupport::BroadcastLogger.new
broadcast_logger.broadcast_to(Logger.new(STDOUT), Logger.new(STDERR))
πŸ“ Source code 
# File activesupport/lib/active_support/broadcast_logger.rb, line 92
    def broadcast_to(*loggers)
      @broadcasts.concat(loggers)
    end
πŸ”Ž See on GitHub

debug!()

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

πŸ“ Source code 
# File activesupport/lib/active_support/broadcast_logger.rb, line 146
    def debug!
      dispatch(:debug!)
    end
πŸ”Ž See on GitHub

debug?()

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

πŸ“ Source code 
# File activesupport/lib/active_support/broadcast_logger.rb, line 141
    def debug?
      @broadcasts.any? { |logger| logger.debug? }
    end
πŸ”Ž See on GitHub

error!()

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

πŸ“ Source code 
# File activesupport/lib/active_support/broadcast_logger.rb, line 179
    def error!
      dispatch(:error!)
    end
πŸ”Ž See on GitHub

error?()

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

πŸ“ Source code 
# File activesupport/lib/active_support/broadcast_logger.rb, line 174
    def error?
      @broadcasts.any? { |logger| logger.error? }
    end
πŸ”Ž See on GitHub

fatal!()

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

πŸ“ Source code 
# File activesupport/lib/active_support/broadcast_logger.rb, line 190
    def fatal!
      dispatch(:fatal!)
    end
πŸ”Ž See on GitHub

fatal?()

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

πŸ“ Source code 
# File activesupport/lib/active_support/broadcast_logger.rb, line 185
    def fatal?
      @broadcasts.any? { |logger| logger.fatal? }
    end
πŸ”Ž See on GitHub

info!()

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

πŸ“ Source code 
# File activesupport/lib/active_support/broadcast_logger.rb, line 157
    def info!
      dispatch(:info!)
    end
πŸ”Ž See on GitHub

info?()

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

πŸ“ Source code 
# File activesupport/lib/active_support/broadcast_logger.rb, line 152
    def info?
      @broadcasts.any? { |logger| logger.info? }
    end
πŸ”Ž See on GitHub

initialize_copy(other)

πŸ“ Source code 
# File activesupport/lib/active_support/broadcast_logger.rb, line 194
    def initialize_copy(other)
      @broadcasts = []
      @progname = other.progname.dup

      broadcast_to(*other.broadcasts.map(&:dup))
    end
πŸ”Ž See on GitHub

level()

Returns the lowest level of all the loggers in the broadcast.

πŸ“ Source code 
# File activesupport/lib/active_support/broadcast_logger.rb, line 135
    def level
      @broadcasts.map(&:level).min
    end
πŸ”Ž See on GitHub

local_level()

πŸ“ Source code 
# File activesupport/lib/active_support/broadcast_logger.rb, line 113
    def local_level
      loggers = @broadcasts.select { |logger| logger.respond_to?(:local_level) }

      loggers.map do |logger|
        logger.local_level
      end.first
    end
πŸ”Ž See on GitHub

local_level=(level)

πŸ“ Source code 
# File activesupport/lib/active_support/broadcast_logger.rb, line 107
    def local_level=(level)
      @broadcasts.each do |logger|
        logger.local_level = level if logger.respond_to?(:local_level=)
      end
    end
πŸ”Ž See on GitHub

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)
πŸ“ Source code 
# File activesupport/lib/active_support/broadcast_logger.rb, line 103
    def stop_broadcasting_to(logger)
      @broadcasts.delete(logger)
    end
πŸ”Ž See on GitHub

warn!()

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

πŸ“ Source code 
# File activesupport/lib/active_support/broadcast_logger.rb, line 168
    def warn!
      dispatch(:warn!)
    end
πŸ”Ž See on GitHub

warn?()

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

πŸ“ Source code 
# File activesupport/lib/active_support/broadcast_logger.rb, line 163
    def warn?
      @broadcasts.any? { |logger| logger.warn? }
    end
πŸ”Ž See on GitHub