class Lumberjack::Formatter

This class controls the conversion of log entry messages into a loggable format. This allows you to log any object you want and have the logging system deal with converting it into a string.

Formats are added to a Formatter by associating them with a class using the add method. Formats are any object that responds to the call method.

By default, all object will be converted to strings using their inspect method except for Strings and Exceptions. Strings are not converted and Exceptions are converted using the ExceptionFormatter.

Enumerable objects (including Hash and Array) will call the formatter recursively for each element.

Public Class Methods

empty() click to toggle source

Returns a new empty formatter with no mapping. For historical reasons, a formatter is initialized with mappings to help output objects as strings. This will return one without the default mappings.

# File lib/lumberjack/formatter.rb, line 29
def empty
  new.clear
end
new() click to toggle source
# File lib/lumberjack/formatter.rb, line 34
def initialize
  @class_formatters = {}
  @module_formatters = {}
  structured_formatter = StructuredFormatter.new(self)
  add([String, Numeric, TrueClass, FalseClass], :object)
  add(Object, InspectFormatter.new)
  add(Exception, :exception)
  add(Enumerable, structured_formatter)
end

Public Instance Methods

add(klass, formatter = nil, &block) click to toggle source

Add a formatter for a class. The formatter can be specified as either an object that responds to the call method or as a symbol representing one of the predefined formatters, or as a block to the method call.

The predefined formatters are: :inspect, :string, :exception, and :pretty_print.

You can add multiple classes at once by passing an array of classes.

You can also pass class names as strings instead of the classes themselves. This can help avoid loading dependency issues. This applies only to classes; modules cannot be passed in as strings.

Examples

# Use a predefined formatter
formatter.add(MyClass, :pretty_print)

# Pass in a formatter object
formatter.add(MyClass, Lumberjack::Formatter::PrettyPrintFormatter.new)

# Use a block
formatter.add(MyClass){|obj| obj.humanize}

# Add statements can be chained together
formatter.add(MyClass, :pretty_print).add(YourClass){|obj| obj.humanize}
# File lib/lumberjack/formatter.rb, line 69
def add(klass, formatter = nil, &block)
  formatter ||= block
  if formatter.nil?
    remove(klass)
  else
    if formatter.is_a?(Symbol)
      formatter_class_name = "#{formatter.to_s.gsub(/(^|_)([a-z])/) { |m| $~[2].upcase }}Formatter"
      formatter = Formatter.const_get(formatter_class_name).new
    end

    Array(klass).each do |k|
      if k.class == Module
        @module_formatters[k] = formatter
      else
        k = k.name if k.is_a?(Class)
        @class_formatters[k] = formatter
      end
    end
  end
  self
end
call(severity, timestamp, progname, msg) click to toggle source

Compatibility with the Logger::Formatter signature. This method will just convert the message object to a string and ignores the other parameters.

# File lib/lumberjack/formatter.rb, line 129
def call(severity, timestamp, progname, msg)
  "#{format(msg)}#{Lumberjack::LINE_SEPARATOR}"
end
clear() click to toggle source

Remove all formatters including the default formatter. Can be chained to add method calls.

# File lib/lumberjack/formatter.rb, line 111
def clear
  @class_formatters.clear
  @module_formatters.clear
  self
end
format(message) click to toggle source

Format a message object as a string.

# File lib/lumberjack/formatter.rb, line 118
def format(message)
  formatter = formatter_for(message.class)
  if formatter&.respond_to?(:call)
    formatter.call(message)
  else
    message
  end
end
remove(klass) click to toggle source

Remove the formatter associated with a class. Remove statements can be chained together.

You can remove multiple classes at once by passing an array of classes.

You can also pass class names as strings instead of the classes themselves. This can help avoid loading dependency issues. This applies only to classes; modules cannot be passed in as strings.

# File lib/lumberjack/formatter.rb, line 98
def remove(klass)
  Array(klass).each do |k|
    if k.class == Module
      @module_formatters.delete(k)
    else
      k = k.name if k.is_a?(Class)
      @class_formatters.delete(k)
    end
  end
  self
end