Class: Log4r::PatternFormatter

Inherits:
BasicFormatter show all
Defined in:
lib/log4r/formatter/patternformatter.rb

Overview

See log4r/formatter/patternformatter.rb

Constant Summary collapse

DirectiveTable =

Arguments to sprintf keyed to directive letters
%c - event short name
%C - event fullname
%d - date
%g - Global Diagnostic Context (GDC)
%t - trace
%m - message
%h - thread name
%p - process ID aka PID
%M - formatted message
%l - Level in string form
%x - Nested Diagnostic Context (NDC)
%X - Mapped Diagnostic Context (MDC), syntax is “%Xkey”
%% - Insert a %

{
  "c" => 'event.name',
  "C" => 'event.fullname',
  "d" => 'format_date',
  "g" => 'Log4r::GDC.get()',
  "t" => '(event.tracer.nil? ? "no trace" : event.tracer[0])',
  "T" => '(event.tracer.nil? ? "no trace" : event.tracer[0].split(File::SEPARATOR)[-1])',
  "m" => 'event.data',
  "h" => '(Thread.current[:name] or Thread.current.to_s)',
  "p" => 'Process.pid.to_s',
  "M" => 'format_object(event.data)',
  "l" => 'LNAMES[event.level]',
  "x" => 'Log4r::NDC.get()',
  "X" => 'Log4r::MDC.get("DTR_REPLACE")',
  "%" => '"%"'
}
DirectiveRegexp =

Matches the first directive encountered and the stuff around it.

  • $1 is the stuff before directive or “” if not applicable

  • $2 is the directive group or nil if there’s none

  • $3 is the %#.# match within directive group

  • $4 is the .# match which we don’t use (it’s there to match properly)

  • $5 is the directive letter

  • $6 is the stuff after the directive or “” if not applicable

  • $7 is the remainder

/([^%]*)((%-?\d*(\.\d+)?)([cCdgtTmhpMlxX%]))?(\{.+?\})?(.*)/
ISO8601 =

default date format

"%Y-%m-%d %H:%M:%S"

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from BasicFormatter

#format, #format_object

Methods inherited from SimpleFormatter

#format

Methods inherited from Formatter

#format

Constructor Details

#initialize(hash = {}) ⇒ PatternFormatter

Accepts the following hash arguments (either a string or a symbol):

pattern

A pattern format string.

date_pattern

A Time#strftime format string. See the Ruby Time class for details.

date_method

As an option to date_pattern, specify which Time.now method to call. For example, usec or to_s. Specify it as a String or Symbol.

The default date format is ISO8601, which looks like this:

yyyy-mm-dd hh:mm:ss    =>    2001-01-12 13:15:50



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# File 'lib/log4r/formatter/patternformatter.rb', line 79

def initialize(hash={})
  super(hash)
  @pattern = (hash['pattern'] or hash[:pattern] or nil)
  @date_pattern = (hash['date_pattern'] or hash[:date_pattern] or nil)
  @date_method = (hash['date_method'] or hash[:date_method] or nil)
  @date_pattern = ISO8601 if @date_pattern.nil? and @date_method.nil?
  PatternFormatter.create_format_methods(self)
end

Instance Attribute Details

#date_method ⇒ Object (readonly)

Returns the value of attribute date_method.



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# File 'lib/log4r/formatter/patternformatter.rb', line 62

def date_method
  @date_method
end

#date_pattern ⇒ Object (readonly)

Returns the value of attribute date_pattern.



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# File 'lib/log4r/formatter/patternformatter.rb', line 62

def date_pattern
  @date_pattern
end

#pattern ⇒ Object (readonly)

Returns the value of attribute pattern.



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# File 'lib/log4r/formatter/patternformatter.rb', line 62

def pattern
  @pattern
end

Class Method Details

.create_format_methods(pf) ⇒ Object

PatternFormatter works by dynamically defining a format method based on the supplied pattern format. This method contains a call to Kernel#sptrintf with arguments containing the data requested in the pattern format.

How is this magic accomplished? First, we visit each directive and change the %#.# component to %#.#s. The directive letter is then used to cull an appropriate entry from the DirectiveTable for the sprintf argument list. After assembling the method definition, we run module_eval on it, and voila.



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# File 'lib/log4r/formatter/patternformatter.rb', line 99

def PatternFormatter.create_format_methods(pf) #:nodoc:
  # first, define the format_date method
  if pf.date_method
    module_eval "def pf.format_date; Time.now.#{pf.date_method}; end"
  else
    module_eval <<-EOS
      def pf.format_date
        Time.now.strftime "#{pf.date_pattern}"
      end
    EOS
  end
  # and now the main format method
  ebuff = "def pf.format(event)\n sprintf(\""
  _pattern = pf.pattern.dup
  args = [] # the args to sprintf which we'll append to ebuff lastly
  while true # work on each match in turn
    match = DirectiveRegexp.match _pattern
    ebuff << match[1] unless match[1].empty?
    break if match[2].nil?
    # deal with the directive by inserting a %#.#s where %#.# is copied
    # directy from the match
    ebuff << match[3] + "s"

	if ( match[5] == 'X' && match[6] != nil ) then

	  # MDC matches, need to be able to handle String, Symbol or Number
	  match6sub = /[\{\}\"]/
	  mdcmatches = match[6].match /\{(:?)(\d*)(.*)\}/

	  if ( mdcmatches[1] == "" && mdcmatches[2] == "" )
 match6sub = /[\{\}]/ # don't remove surrounding "'s if String
	  end
	  
	  args <<
 DirectiveTable[match[5]].gsub("DTR_REPLACE", match[6]).gsub(match6sub,'')
	else
	  args << DirectiveTable[match[5]]  # cull the data for our argument list
	end
    break if match[7].empty?
    _pattern = match[7]
  end
  ebuff << '\n", ' + args.join(', ') + ")\n"
  ebuff << "end\n"
  module_eval ebuff
end