require "time" # httpdate
# ==== Public Merb Logger API
#
# To replace an existing logger with a new one:
# Merb::Logger.set_log(log{String, IO},level{Symbol, String})
#
# Available logging levels are
# Merb::Logger::{ Fatal, Error, Warn, Info, Debug }
#
# Logging via:
# Merb.logger.fatal(message<String>,&block)
# Merb.logger.error(message<String>,&block)
# Merb.logger.warn(message<String>,&block)
# Merb.logger.info(message<String>,&block)
# Merb.logger.debug(message<String>,&block)
#
# Logging with autoflush:
# Merb.logger.fatal!(message<String>,&block)
# Merb.logger.error!(message<String>,&block)
# Merb.logger.warn!(message<String>,&block)
# Merb.logger.info!(message<String>,&block)
# Merb.logger.debug!(message<String>,&block)
#
# Flush the buffer to
# Merb.logger.flush
#
# Remove the current log object
# Merb.logger.close
#
# ==== Private Merb Logger API
#
# To initialize the logger you create a new object, proxies to set_log.
# Merb::Logger.new(log{String, IO},level{Symbol, String})
module Merb
class << self #:nodoc:
attr_accessor :logger
end
class Logger
attr_accessor :aio
attr_accessor :level
attr_accessor :delimiter
attr_accessor :auto_flush
attr_reader :buffer
attr_reader :log
attr_reader :init_args
# ==== Notes
# Ruby (standard) logger levels:
# :fatal:: An unhandleable error that results in a program crash
# :error:: A handleable error condition
# :warn:: A warning
# :info:: generic (useful) information about system operation
# :debug:: low-level information for developers
Levels =
{
:fatal => 7,
:error => 6,
:warn => 4,
:info => 3,
:debug => 0
}
private
# Define the write method based on if asynchronous IO an be used.
#
# ==== Notes
# The idea here is that instead of performing an 'if' conditional check on
# each logging we do it once when the log object is setup.
def set_write_method
@log.instance_eval do
# ==== Returns
# Boolean:: True if asynchronous IO can be used.
def aio?
@aio = !Merb.environment.to_s.match(/development|test/) &&
!RUBY_PLATFORM.match(/java|mswin/) &&
!(@log == STDOUT) &&
@log.respond_to?(:write_nonblock)
end
undef write_method if defined? write_method #:nodoc:
if aio?
alias :write_method :write_nonblock
else
alias :write_method :write
end
end
end
# Readies a log for writing.
#
# ==== Parameters
# log<IO, String>:: Either an IO object or a name of a logfile.
def initialize_log(log)
close if @log # be sure that we don't leave open files laying around.
if log.respond_to?(:write)
@log = log
elsif File.exist?(log)
@log = open(log, (File::WRONLY | File::APPEND))
@log.sync = true
else
FileUtils.mkdir_p(File.dirname(log)) unless File.directory?(File.dirname(log))
@log = open(log, (File::WRONLY | File::APPEND | File::CREAT))
@log.sync = true
@log.write("#{Time.now.httpdate} #{delimiter} info #{delimiter} Logfile created\n")
end
set_write_method
end
public
# To initialize the logger you create a new object, proxies to set_log.
#
# ==== Parameters
# *args:: Arguments to create the log from. See set_logs for specifics.
def initialize(*args)
@init_args = args
set_log(*args)
end
# Replaces an existing logger with a new one.
#
# ==== Parameters
# log<IO, String>:: Either an IO object or a name of a logfile.
# log_level<~to_sym>::
# The log level from, e.g. :fatal or :info. Defaults to :error in the
# production environment and :debug otherwise.
# delimiter<String>::
# Delimiter to use between message sections. Defaults to " ~ ".
# auto_flush<Boolean>::
# Whether the log should automatically flush after new messages are
# added. Defaults to false.
def set_log(log, log_level = nil, delimiter = " ~ ", auto_flush = false)
if log_level && Levels[log_level.to_sym]
@level = Levels[log_level.to_sym]
elsif Merb.environment == "production"
@level = Levels[:warn]
else
@level = Levels[:debug]
end
@buffer = []
@delimiter = delimiter
@auto_flush = auto_flush
initialize_log(log)
Merb.logger = self
end
# Flush the entire buffer to the log object.
def flush
return unless @buffer.size > 0
@log.write_method(@buffer.slice!(0..-1).to_s)
end
# Close and remove the current log object.
def close
flush
@log.close if @log.respond_to?(:close)
@log = nil
end
# Appends a message to the log. The methods yield to an optional block and
# the output of this block will be appended to the message.
#
# ==== Parameters
# string<String>:: The message to be logged. Defaults to nil.
#
# ==== Returns
# String:: The resulting message added to the log file.
def <<(string = nil)
message = ""
message << delimiter
message << string if string
message << "\n" unless message[-1] == ?\n
@buffer << message
flush if @auto_flush
message
end
alias :push :<<
# Generate the logging methods for Merb.logger for each log level.
Levels.each_pair do |name, number|
class_eval <<-LEVELMETHODS, __FILE__, __LINE__
# Appends a message to the log if the log level is at least as high as
# the log level of the logger.
#
# ==== Parameters
# string<String>:: The message to be logged. Defaults to nil.
#
# ==== Returns
# self:: The logger object for chaining.
def #{name}(message = nil)
self << message if #{number} >= level
self
end
# Appends a message to the log if the log level is at least as high as
# the log level of the logger. The bang! version of the method also auto
# flushes the log buffer to disk.
#
# ==== Parameters
# string<String>:: The message to be logged. Defaults to nil.
#
# ==== Returns
# self:: The logger object for chaining.
def #{name}!(message = nil)
self << message if #{number} >= level
flush if #{number} >= level
self
end
# ==== Returns
# Boolean:: True if this level will be logged by this logger.
def #{name}?
#{number} >= level
end
LEVELMETHODS
end
end
end
