class Logging::ColorScheme
ColorScheme objects encapsulate a named set
of colors to be used in the colors() method call. For example, by applying
a ColorScheme that has a
:warning
color then the following could be used:
scheme.color("This is a warning", :warning)
ColorScheme objects are used by the Pattern layout code to colorize log messages. Each color scheme is given a unique name which is used by the Pattern layout to lookup the appropriate color scheme to use. Please refer to the Pattern layout documentation for more details - specifically the initializer documentation.
The color scheme can be applied to the Pattern layout in several ways. Each token in the log pattern can be colorized with the log level (debug, info, warn, etc) receiving unique colors based on the level itself. Another option is to colorize the entire log message based on the log level; in this mode tokens do not get their own colors. Please see the ColorScheme initializer for the list of colorization options.
Constants
- BLACK
- BLINK
- BLUE
- BOLD
- BRIGHT_BLUE
- BRIGHT_CYAN
- BRIGHT_GREEN
- BRIGHT_MAGENTA
- BRIGHT_RED
- BRIGHT_WHITE
- BRIGHT_YELLOW
- CLEAR
Embed in a String to clear all previous ANSI sequences. This MUST be done before the program exits!
- CONCEALED
- CYAN
- DARK
- ERASE_CHAR
- ERASE_LINE
- GREEN
- MAGENTA
- ON_BLACK
- ON_BLUE
- ON_BRIGHT_BLUE
- ON_BRIGHT_CYAN
- ON_BRIGHT_GREEN
- ON_BRIGHT_MAGENTA
- ON_BRIGHT_RED
- ON_BRIGHT_WHITE
- ON_BRIGHT_YELLOW
- ON_CYAN
- ON_GREEN
- ON_MAGENTA
- ON_RED
- ON_WHITE
- ON_YELLOW
- RED
- RESET
- REVERSE
- UNDERLINE
- UNDERSCORE
- WHITE
- YELLOW
Public Class Methods
Retrieve a color scheme by name.
# File lib/logging/color_scheme.rb, line 36 def []( name ) @color_schemes[name.to_s] end
Store a color scheme by name.
# File lib/logging/color_scheme.rb, line 42 def []=( name, value ) raise ArgumentError, "Silly! That's not a ColorSchmeme!" unless value.is_a?(ColorScheme) @color_schemes[name.to_s] = value end
Create a ColorScheme instance that can be accessed using the given name. If a color scheme already exists with the given name it will be replaced by the new color scheme.
The color names are passed as options to the method with each name mapping to one or more color codes. For example:
ColorScheme.new('example', :logger => [:white, :on_green], :message => :magenta)
The color codes are the lowercase names of the constants defined at the end of this file. Multiple color codes can be aliased by grouping them in an array as shown in the example above.
Since color schemes are primarily intended to be used with the Pattern layout, there are a few special options of note. First the log levels are enumerated in their own hash:
:levels => { :debug => :blue, :info => :cyan, :warn => :yellow, :error => :red, :fatal => [:white, :on_red] }
The log level token will be colorized differently based on the value of the log level itself. Similarly the entire log message can be colorized based on the value of the log level. A different option should be given for this behavior:
:lines => { :debug => :blue, :info => :cyan, :warn => :yellow, :error => :red, :fatal => [:white, :on_red] }
The :levels and :lines options cannot be used together; only one or the other should be given.
The remaining tokens defined in the Pattern layout can be colorized using the following aliases. Their meaning in the Pattern layout are repeated here for sake of clarity.
:logger [%c] name of the logger that generate the log event :date [%d] datestamp :message [%m] the user supplied log message :pid [%p] PID of the current process :time [%r] the time in milliseconds since the program started :thread [%T] the name of the thread Thread.current[:name] :thread_id [%t] object_id of the thread :file [%F] filename where the logging request was issued :line [%L] line number where the logging request was issued :method [%M] method name where the logging request was issued
Please refer to the “examples/colorization.rb” file for a working example of log colorization.
# File lib/logging/color_scheme.rb, line 121 def initialize( name, opts = {} ) @scheme = Hash.new @lines = opts.key? :lines @levels = opts.key? :levels raise ArgumentError, "Found both :lines and :levels - only one can be used." if lines? and levels? lines = opts.delete :lines levels = opts.delete :levels load_from_hash(opts) load_from_hash(lines) if lines? load_from_hash(levels) if levels? ::Logging::ColorScheme[name] = self end
Clear all color schemes and setup a default color scheme.
# File lib/logging/color_scheme.rb, line 49 def reset @color_schemes ||= {} @color_schemes.clear new(:default, :levels => { :info => :green, :warn => :yellow, :error => :red, :fatal => [:white, :on_red] }) end
Public Instance Methods
Allow the scheme to be accessed like a Hash.
# File lib/logging/color_scheme.rb, line 166 def []( color_tag ) @scheme[to_key(color_tag)] end
Allow the scheme to be set like a Hash.
# File lib/logging/color_scheme.rb, line 172 def []=( color_tag, constants ) @scheme[to_key(color_tag)] = constants.respond_to?(:map) ? constants.map { |c| to_constant(c) }.join : to_constant(constants) end
This method provides easy access to ANSI color sequences, without the user needing to remember to CLEAR at the end of each sequence. Just pass the string to color, followed by a list of colors you would like it to be affected by. The colors can be ColorScheme class constants, or symbols (:blue for BLUE, for example). A CLEAR will automatically be embedded to the end of the returned String.
# File lib/logging/color_scheme.rb, line 184 def color( string, *colors ) colors.map! { |color| color_tag = to_key(color) @scheme.key?(color_tag) ? @scheme[color_tag] : to_constant(color) } colors.compact! return string if colors.empty? "#{colors.join}#{string}#{CLEAR}" end
Does this color scheme include the given tag name?
# File lib/logging/color_scheme.rb, line 160 def include?( color_tag ) @scheme.key?(to_key(color_tag)) end
Returns true
if the :levels option was passed to the
constructor.
# File lib/logging/color_scheme.rb, line 154 def levels? @levels end
Returns true
if the :lines option was passed to the
constructor.
# File lib/logging/color_scheme.rb, line 148 def lines? @lines end
Load multiple colors from key/value pairs.
# File lib/logging/color_scheme.rb, line 140 def load_from_hash( h ) h.each_pair do |color_tag, constants| self[color_tag] = constants end end
Private Instance Methods
Return a normalized representation of a color setting.
# File lib/logging/color_scheme.rb, line 206 def to_constant( v ) v = v.to_s.upcase ColorScheme.const_get(v) if (ColorScheme.const_defined?(v, false) rescue ColorScheme.const_defined?(v)) end
Return a normalized representation of a color name.
# File lib/logging/color_scheme.rb, line 200 def to_key( t ) t.to_s.downcase end