class ActiveSupport::BroadcastLogger

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 `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]

Attributes

broadcasts[R]

Returns all the logger that are part of this broadcast.

formatter[R]
progname[RW]

Public Class Methods

new(*loggers) click to toggle source
# File lib/active_support/broadcast_logger.rb, line 82
def initialize(*loggers)
  @broadcasts = []
  @progname = "Broadcast"

  broadcast_to(*loggers)
end

Public Instance Methods

<<(message) click to toggle source
# File lib/active_support/broadcast_logger.rb, line 112
def <<(message)
  dispatch { |logger| logger.<<(message) }
end
add(*args, &block) click to toggle source
# File lib/active_support/broadcast_logger.rb, line 116
def add(*args, &block)
  dispatch { |logger| logger.add(*args, &block) }
end
Also aliased as: log
broadcast_to(*loggers) click to toggle source

Add logger(s) to the broadcast.

broadcast_logger = ActiveSupport::BroadcastLogger.new
broadcast_logger.broadcast_to(Logger.new(STDOUT), Logger.new(STDERR))
# File lib/active_support/broadcast_logger.rb, line 93
def broadcast_to(*loggers)
  @broadcasts.concat(loggers)
end
close() click to toggle source
# File lib/active_support/broadcast_logger.rb, line 162
def close
  dispatch { |logger| logger.close }
end
debug(*args, &block) click to toggle source
# File lib/active_support/broadcast_logger.rb, line 121
def debug(*args, &block)
  dispatch { |logger| logger.debug(*args, &block) }
end
debug!() click to toggle source

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

# File lib/active_support/broadcast_logger.rb, line 173
def debug!
  dispatch { |logger| logger.debug! }
end
debug?() click to toggle source

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

# File lib/active_support/broadcast_logger.rb, line 168
def debug?
  @broadcasts.any? { |logger| logger.debug? }
end
error(*args, &block) click to toggle source
# File lib/active_support/broadcast_logger.rb, line 133
def error(*args, &block)
  dispatch { |logger| logger.error(*args, &block) }
end
error!() click to toggle source

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

# File lib/active_support/broadcast_logger.rb, line 206
def error!
  dispatch { |logger| logger.error! }
end
error?() click to toggle source

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

# File lib/active_support/broadcast_logger.rb, line 201
def error?
  @broadcasts.any? { |logger| logger.error? }
end
fatal(*args, &block) click to toggle source
# File lib/active_support/broadcast_logger.rb, line 137
def fatal(*args, &block)
  dispatch { |logger| logger.fatal(*args, &block) }
end
fatal!() click to toggle source

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

# File lib/active_support/broadcast_logger.rb, line 217
def fatal!
  dispatch { |logger| logger.fatal! }
end
fatal?() click to toggle source

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

# File lib/active_support/broadcast_logger.rb, line 212
def fatal?
  @broadcasts.any? { |logger| logger.fatal? }
end
formatter=(formatter) click to toggle source
# File lib/active_support/broadcast_logger.rb, line 145
def formatter=(formatter)
  dispatch { |logger| logger.formatter = formatter }

  @formatter = formatter
end
info(*args, &block) click to toggle source
# File lib/active_support/broadcast_logger.rb, line 125
def info(*args, &block)
  dispatch { |logger| logger.info(*args, &block) }
end
info!() click to toggle source

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

# File lib/active_support/broadcast_logger.rb, line 184
def info!
  dispatch { |logger| logger.info! }
end
info?() click to toggle source

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

# File lib/active_support/broadcast_logger.rb, line 179
def info?
  @broadcasts.any? { |logger| logger.info? }
end
initialize_copy(other) click to toggle source
# File 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
level() click to toggle source
# File lib/active_support/broadcast_logger.rb, line 108
def level
  @broadcasts.map(&:level).min
end
level=(level) click to toggle source
# File lib/active_support/broadcast_logger.rb, line 151
def level=(level)
  dispatch { |logger| logger.level = level }
end
Also aliased as: sev_threshold=
local_level=(level) click to toggle source
# File 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
log(*args, &block)
Alias for: add
sev_threshold=(level)
Alias for: level=
stop_broadcasting_to(logger) click to toggle source

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)
# File lib/active_support/broadcast_logger.rb, line 104
def stop_broadcasting_to(logger)
  @broadcasts.delete(logger)
end
unknown(*args, &block) click to toggle source
# File lib/active_support/broadcast_logger.rb, line 141
def unknown(*args, &block)
  dispatch { |logger| logger.unknown(*args, &block) }
end
warn(*args, &block) click to toggle source
# File lib/active_support/broadcast_logger.rb, line 129
def warn(*args, &block)
  dispatch { |logger| logger.warn(*args, &block) }
end
warn!() click to toggle source

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

# File lib/active_support/broadcast_logger.rb, line 195
def warn!
  dispatch { |logger| logger.warn! }
end
warn?() click to toggle source

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

# File lib/active_support/broadcast_logger.rb, line 190
def warn?
  @broadcasts.any? { |logger| logger.warn? }
end

Private Instance Methods

dispatch(&block) click to toggle source
# File lib/active_support/broadcast_logger.rb, line 230
def dispatch(&block)
  @broadcasts.each { |logger| block.call(logger) }
end
method_missing(name, *args, **kwargs, &block) click to toggle source
Calls superclass method
# File lib/active_support/broadcast_logger.rb, line 234
def method_missing(name, *args, **kwargs, &block)
  loggers = @broadcasts.select { |logger| logger.respond_to?(name) }

  if loggers.none?
    super(name, *args, **kwargs, &block)
  elsif loggers.one?
    loggers.first.send(name, *args, **kwargs, &block)
  else
    loggers.map { |logger| logger.send(name, *args, **kwargs, &block) }
  end
end
respond_to_missing?(method, include_all) click to toggle source
# File lib/active_support/broadcast_logger.rb, line 246
def respond_to_missing?(method, include_all)
  @broadcasts.any? { |logger| logger.respond_to?(method, include_all) }
end