Class: Arrow::Logger

Inherits:
Object
  • Object
show all
Extends:
Logger::DebugLogger, Configurability
Includes:
Logger::DebugLogger
Defined in:
lib/arrow/logger.rb

Overview

A hierarchical logging class for the Arrow framework. It provides a generalized means of logging from inside Arrow classes, and then selectively outputting/formatting log messages from points within the hierarchy.

A lot of concepts in this class were stolen from Log4r, though it’s all original code, and works a bit differently.

Synopsis

  
  require 'arrow/object'
  require 'arrow/logger'
  
  logger = Arrow::Logger.global
  logfile = File.open( "global.log", "a" )
  logger.outputters << Arrow::Logger::Outputter.new(logfile)
  logger.level = :debug

  class MyClass < Arrow::Object

      def self::fooMethod
          Arrow::Logger.debug( "In server start routine" )
          Arrow::Logger.info( "Server is not yet configured." )
          Arrow::Logger.notice( "Server is starting up." )
      end

      def initialize
          self.log.info( "Initializing another MyClass object." )
      end
  end

VCS Id

  $Id: logger.rb,v ba725438313d 2010/08/09 02:08:40 ged $

Authors

  • Michael Granger

Please see the file LICENSE in the top-level directory for licensing details.

Defined Under Namespace

Modules: DebugLogger Classes: ApacheOutputter, ArrayOutputter, ColorOutputter, FileOutputter, HtmlOutputter, Outputter

Constant Summary

LEVELS =

Construct a log levels Hash on the fly 

[
  :debug,
  :info,
  :notice,
  :warning,
  :error,
  :crit,
  :alert,
  :emerg,
].inject({}) {
LEVEL_NAMES = 
LEVELS.invert

Class Attribute Summary

Instance Attribute Summary

Class Method Summary

Instance Method Summary

Methods included from Logger::DebugLogger

debug_msg

Methods included from Logger::DebugLogger

debug_msg

Constructor Details

- (Logger) initialize(mod, level = :info, *outputters)

Create and return a new Arrow::Logger object for the given mod (a Module object). If It will be configured at the given level. Any outputters that are specified will be added. 



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# File 'lib/arrow/logger.rb', line 208

def initialize( mod, level=:info, *outputters )
  @module     = mod
  @outputters = outputters
  @trace      = false
  @level      = nil

  # Cached Array of modules and classes between 
  # this logger's module and Object
  @supermods  = nil

  # Level to force messages written to this logger to
  @forced_level = nil

  self.level  = level
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

- (Object) method_missing(sym, *args) (protected)

Auto-install logging methods (ie., methods whose names match one of Arrow::Logger::LEVELS. 



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# File 'lib/arrow/logger.rb', line 451

def method_missing( sym, *args )
  name = sym.to_s
  level = name[/\w+/].to_sym
  return super unless Arrow::Logger::LEVELS.member?( level )
  code = nil

  case name
  when /^\w+\?/
    code = self.make_level_predicate_method( level )

  when /^\w+$/
    code = self.make_writer_method( level )

  else
    return super
  end

  self.class.send( :define_method, sym, &code )
  return self.method( sym ).call( *args )
end

Class Attribute Details

+ (Object) logger_map (readonly)

Returns the value of attribute logger_map 



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# File 'lib/arrow/logger.rb', line 87

def logger_map
  @logger_map
end

Instance Attribute Details

- (Object) forced_level

The level to force messages written to this logger to 



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# File 'lib/arrow/logger.rb', line 242

def forced_level
  @forced_level
end

- (Object) level

The integer level of the logger. 



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# File 'lib/arrow/logger.rb', line 239

def level
  @level
end

- (Object) module (readonly)

The module this logger is associated with 



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# File 'lib/arrow/logger.rb', line 230

def module
  @module
end

- (Object) outputters

The outputters attached to this branch of the logger tree. 



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# File 'lib/arrow/logger.rb', line 233

def outputters
  @outputters
end

- (Object) trace

Set to a true value to turn tracing on 



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# File 'lib/arrow/logger.rb', line 236

def trace
  @trace
end

Class Method Details

+ (Object) [](mod = nil)

Return the Arrow::Logger for the given module mod, which can be a Module object, a Symbol, or a String. 



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# File 'lib/arrow/logger.rb', line 151

def self::[]( mod=nil )
  return self.global if mod.nil?

  case mod
  when Module
    return self.logger_map[ mod ]

  # If it's a String, try to map it to a class name, falling back on the global
  # logger if that fails
  when String
    mod = mod.split('::').
      inject( Object ) {|k, modname| k.const_get(modname) } rescue Object
    return self.logger_map[ mod ]
  else

    return self.logger_map[ mod.class ]
  end

end

+ (Object) configure(config)

Configure logging from the ‘logging’ section of the config. 



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# File 'lib/arrow/logger.rb', line 91

def self::configure( config )

self.reset
apacheoutputter = Arrow::Logger::Outputter.create( 'apache' )

config.each do |klass, setting|
  level, uri = self.parse_log_setting( setting )

  # Use the Apache log as the outputter if none is configured
  if uri.nil?
    outputter = apacheoutputter
  else
    outputter = Arrow::Logger::Outputter.create( uri )
  end

  # The 'global' entry configures the global logger
  if klass == :global
    self.global.level = level
    self.global.outputters << outputter
    next
  end

  # If the class bit is something like 'applet', then transform
  # it into 'Arrow::Applet'
  if klass.to_s.match( /^[a-z][a-zA-Z]+$/ )
    realclass = "Arrow::%s" % klass.to_s.sub(/^([a-z])/){ $1.upcase }
  else
    realclass = klass.to_s
  end

  Arrow::Logger[ realclass ].level = level
  Arrow::Logger[ realclass ].outputters << outputter
end

end

+ (Object) global

Return the global Arrow logger, setting it up if it hasn’t been already. 



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# File 'lib/arrow/logger.rb', line 174

def self::global
  self.logger_map[ Object ]
end

+ (Object) method_missing(sym, *args)

Autoload global logging methods for the log levels 



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# File 'lib/arrow/logger.rb', line 187

def self::method_missing( sym, *args )
  return super unless LEVELS.key?( sym )

  self.global.debug( "Autoloading class log method '#{sym}'." )
  (class << self; self; end).class_eval do
    define_method( sym ) do |*args|
      self.global.send( sym, *args )
    end
  end

  self.global.send( sym, *args )
end

+ (Object) parse_log_setting(setting)

Parse the configuration for a given class’s logger. The configuration is in the form: 

  <level> [<outputter_uri>]

where level is one of the logging levels defined by this class (see the LEVELS constant), and the optional outputter_uri indicates which outputter to use, and how it should be configured. See Arrow::Logger::Outputter for more info.

Examples: 

  notice
  debug file:///tmp/broker-debug.log
  error dbi://www:password@localhost/www.errorlog?driver=postgresql



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# File 'lib/arrow/logger.rb', line 141

def self::parse_log_setting( setting )
  level, rawuri = setting.split( ' ', 2 )
  uri = rawuri.nil? ? nil : URI.parse( rawuri )

  return level.to_sym, uri
end

+ (Object) reset

Reset the logging subsystem. Clears out any registered loggers and their associated outputters. 



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# File 'lib/arrow/logger.rb', line 181

def self::reset
  self.logger_map.clear
end

Instance Method Details

- (Object) <<(obj)

Append the given obj to the logger at :debug level. This is for compatibility with objects that append to $stderr for their logging (e.g., net/protocols-based libraries). 



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# File 'lib/arrow/logger.rb', line 426

def <<( obj )
  self.write( :debug, obj )
  return self
end

- (Object) hierloggers(level = :emerg)

Return a uniquified Array of the loggers which are more-generally related hierarchically to the receiver, inclusive, and whose level is level or lower. 



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# File 'lib/arrow/logger.rb', line 353

def hierloggers( level=:emerg )
  level = LEVELS[ level ] if level.is_a?( Symbol )

  loggers = []
  self.supermods.each do |mod|
    logger = self.class.logger_map[ mod ]
    next unless logger.level <= level

    loggers << logger
    yield( logger ) if block_given?
  end

  return loggers
end

- (Object) hieroutputters(level = LEVELS[:emerg])

Return a uniquified Array of all outputters for this logger and all of the loggers above it in the logging hierarchy that are set to level or lower. If called with a block, it will be called once for each outputter and the first logger to which it is attached. 



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# File 'lib/arrow/logger.rb', line 373

def hieroutputters( level=LEVELS[:emerg] )
  outputters = []

  # Look for loggers which are higher in the hierarchy
  self.hierloggers( level ) do |logger|
    outpary = logger.outputters || []
    newoutpary = outpary - (outpary & outputters)

    # If there are any outputters which haven't already been seen,
    # output to them.
    unless newoutpary.empty?
      # debug_msg "hieroutputters: adding: %s" %
        # newoutpary.collect {|outp| outp.description}.join(", ")
      if block_given?
        newoutpary.each {|outputter| yield(outputter, logger)}
      end
      outputters += newoutpary
    end
  end

  return outputters
end

- (Object) inspect

Return a human-readable string representation of the object. 



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# File 'lib/arrow/logger.rb', line 246

def inspect
  "#<%s:0x%0x %s [level: %s, outputters: %d, trace: %s]>" % [
    self.class.name,
    self.object_id * 2,
    self.readable_name,
    self.readable_level,
    self.outputters.length,
    self.trace ? "on" : "off",
  ]
end

- (Object) inspect_details(level = 0)

Return a (more-detailed) human-readable string representation of the object. 



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# File 'lib/arrow/logger.rb', line 259

def inspect_details( level=0 )
  indent = '  ' * (level + 1)

  prelude = "<< %s [level: %s, trace: %s] >>" % [
    self.readable_name,
    self.readable_level,
    self.trace ? "on" : "off",
    ]

  details = []
  unless self.outputters.empty?
    details << "Outputters:" << self.outputters.map {|op| op.inspect }
  end
  details = details.flatten.compact.map {|line| indent + line }

  if level.zero?
    return [ prelude, *details ].join( "\n" )
  else
    return [ prelude, *details ]
  end
end

- (Object) make_level_predicate_method(level) (protected)

Return a Proc suitable for installing as a predicate method for the given logging level. 



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# File 'lib/arrow/logger.rb', line 475

def make_level_predicate_method( level )
  numeric_level = LEVELS[level]
  Proc.new { self.level < numeric_level }
end

- (Object) make_writer_method(level) (protected)

Return a Proc suitable for installing as a log-writing method for the given logging level. 



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# File 'lib/arrow/logger.rb', line 483

def make_writer_method( level )
  Proc.new {|*args| self.write(level, *args)}
end

- (Object) readable_level

Return the logger’s level as a Symbol. 



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# File 'lib/arrow/logger.rb', line 291

def readable_level
  return LEVEL_NAMES[ @level ]
end

- (Object) readable_name

Return the name of the logger formatted to be suitable for reading. 



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# File 'lib/arrow/logger.rb', line 283

def readable_name
  return '(global)' if self.module == Object
  return self.module.inspect if self.module.name == ''
  return self.module.name
end

- (Object) stringify_object(obj) (protected)

Dump the given object for output in the log. 



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# File 'lib/arrow/logger.rb', line 437

def stringify_object( obj )
  return case obj
       when Exception
         "%s:\n    %s" % [ obj.message, obj.backtrace.join("\n    ") ]
       when String
         obj
       else
         obj.inspect
       end
end

- (Object) superlogger

Return the Arrow::Logger for this instance’s module’s parent class if it’s a Class, and the global logger otherwise. 



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# File 'lib/arrow/logger.rb', line 325

def superlogger
  if @module == Object
    return nil
  elsif @module.respond_to?( :superclass )
    Arrow::Logger[ @module.superclass ]
  else
    Arrow::Logger.global
  end
end

- (Object) supermods

Return the Array of modules and classes the receiver’s module includes or inherits, inclusive of the receiver’s module itself. 



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# File 'lib/arrow/logger.rb', line 338

def supermods
  unless @supermods
    objflag = false
    @supermods = self.module.ancestors.partition {|mod| objflag ||= (mod == Object) }.last
    @supermods << Object
  end

  return @supermods
end

- (Object) write(level, *args)

Write the given args to any connected outputters if level is less than or equal to this logger’s level. 



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# File 'lib/arrow/logger.rb', line 399

def write( level, *args )
  # debug_msg "Writing message at %p from %s: %p" % [ level, caller(2).first, args ]

  msg, frame = nil, nil
  time = Time.now

  # If tracing is turned on, pick the first frame in the stack that
  # isn't in this file, or the last one if that fails to yield one.
  if @trace
    frame = caller(1).find {|fr| fr !~ %r{arrow/logger\.rb} } ||
       caller(1).last
  end

  level = @forced_level if @forced_level

  # Find the outputters that need to be written to, then write to them.
  self.hieroutputters( level ) do |outp, logger|
    # debug_msg "Got outputter %p" % outp
    msg ||= args.collect {|obj| self.stringify_object(obj) }.join
    outp.write( time, level, self.readable_name, frame, msg )
  end
end