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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]

Methods

#

<<

A

add

B

broadcast_to

C

close

D

debug,
debug!,
debug?

E

error,
error!,
error?

F

fatal,
fatal!,
fatal?,
formatter=

I

info,
info!,
info?,
initialize_copy

L

level,
level=,
local_level=,
log

N

new

S

sev_threshold=,
stop_broadcasting_to

U

unknown

W

warn,
warn!,
warn?

Included Modules

ActiveSupport::LoggerSilence

Attributes

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

Class Public methods

new(*loggers) Link

Source: show | on GitHub

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

  broadcast_to(*loggers)
end

Instance Public methods

<<(message) Link

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 112
def <<(message)
  dispatch { |logger| logger.<<(message) }
end

add(*args, &block) Link

Also aliased as: log

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 116
def add(*args, &block)
  dispatch { |logger| logger.add(*args, &block) }
end

broadcast_to(*loggers) Link

Add logger(s) to the broadcast.

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

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 93
def broadcast_to(*loggers)
  @broadcasts.concat(loggers)
end

close() Link

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 162
def close
  dispatch { |logger| logger.close }
end

debug(*args, &block) Link

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 121
def debug(*args, &block)
  dispatch { |logger| logger.debug(*args, &block) }
end

debug!() Link

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

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 173
def debug!
  dispatch { |logger| logger.debug! }
end

debug?() Link

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

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 168
def debug?
  @broadcasts.any? { |logger| logger.debug? }
end

error(*args, &block) Link

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 133
def error(*args, &block)
  dispatch { |logger| logger.error(*args, &block) }
end

error!() Link

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

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 206
def error!
  dispatch { |logger| logger.error! }
end

error?() Link

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

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 201
def error?
  @broadcasts.any? { |logger| logger.error? }
end

fatal(*args, &block) Link

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 137
def fatal(*args, &block)
  dispatch { |logger| logger.fatal(*args, &block) }
end

fatal!() Link

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

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 217
def fatal!
  dispatch { |logger| logger.fatal! }
end

fatal?() Link

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

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 212
def fatal?
  @broadcasts.any? { |logger| logger.fatal? }
end

formatter=(formatter) Link

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 145
def formatter=(formatter)
  dispatch { |logger| logger.formatter = formatter }

  @formatter = formatter
end

info(*args, &block) Link

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 125
def info(*args, &block)
  dispatch { |logger| logger.info(*args, &block) }
end

info!() Link

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

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 184
def info!
  dispatch { |logger| logger.info! }
end

info?() Link

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

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 179
def info?
  @broadcasts.any? { |logger| logger.info? }
end

initialize_copy(other) Link

Source: show | on 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

level() Link

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 108
def level
  @broadcasts.map(&:level).min
end

level=(level) Link

Also aliased as: sev_threshold=

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 151
def level=(level)
  dispatch { |logger| logger.level = level }
end

local_level=(level) Link

Source: show | on 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

log(*args, &block) Link

Alias for: add

sev_threshold=(level) Link

Alias for: level=

stop_broadcasting_to(logger) Link

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)

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 104
def stop_broadcasting_to(logger)
  @broadcasts.delete(logger)
end

unknown(*args, &block) Link

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 141
def unknown(*args, &block)
  dispatch { |logger| logger.unknown(*args, &block) }
end

warn(*args, &block) Link

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 129
def warn(*args, &block)
  dispatch { |logger| logger.warn(*args, &block) }
end

warn!() Link

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

Source: show | on GitHub

# File activesupport/lib/active_support/broadcast_logger.rb, line 195
def warn!
  dispatch { |logger| logger.warn! }
end

warn?() Link

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

Source: show | on GitHub

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