Class: Lumberjack::Formatter

Inherits:
Object
  • Object
show all
Defined in:
lib/lumberjack/formatter.rb,
lib/lumberjack/formatter/id_formatter.rb,
lib/lumberjack/formatter/strip_formatter.rb,
lib/lumberjack/formatter/object_formatter.rb,
lib/lumberjack/formatter/string_formatter.rb,
lib/lumberjack/formatter/inspect_formatter.rb,
lib/lumberjack/formatter/truncate_formatter.rb,
lib/lumberjack/formatter/date_time_formatter.rb,
lib/lumberjack/formatter/exception_formatter.rb,
lib/lumberjack/formatter/structured_formatter.rb,
lib/lumberjack/formatter/pretty_print_formatter.rb

Overview

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.

Direct Known Subclasses

TaggedLoggerSupport::Formatter

Defined Under Namespace

Classes: DateTimeFormatter, ExceptionFormatter, IdFormatter, InspectFormatter, ObjectFormatter, PrettyPrintFormatter, StringFormatter, StripFormatter, StructuredFormatter, TruncateFormatter

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Formatter

Returns a new instance of Formatter.



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# File 'lib/lumberjack/formatter.rb', line 37

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

Class Method Details

.empty ⇒ Lumberjack::Formatter

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.

Returns:



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# File 'lib/lumberjack/formatter.rb', line 32

def empty
  new.clear
end

Instance Method Details

#add(klass, formatter = nil, *args) {|obj| ... } ⇒ self

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:

- :date_time
- :exception
- :id
- :inspect
- :object
- :pretty_print
- :string
- :strip
- :structured
- :truncate

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}

Parameters:

  • klass (Class, Module, String, Array<Class, Module, String>) —

    The class or module to add a formatter for.

  • formatter (Symbol, Class, String, #call) (defaults to: nil) —

    The formatter to use for the class. If a symbol is passed in, it will be used to load one of the predefined formatters. If a class is passed in, it will be initialized with the args passed in. Otherwise, the object will be used as the formatter and must respond to call method.

  • args (Array) —

    Arguments to pass to the formatter when it is initialized.

Yields:

  • (obj) —

    A block that will be used as the formatter for the class.

Yield Parameters:

  • obj (Object) —

    The object to format.

Yield Returns:

  • (String) —

    The formatted string.

Returns:

  • (self) —

    Returns itself so that add statements can be chained together.



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# File 'lib/lumberjack/formatter.rb', line 93

def add(klass, formatter = nil, *args, &block)
  formatter ||= block
  if formatter.nil?
    remove(klass)
  else
    formatter_class_name = nil
    if formatter.is_a?(Symbol)
      formatter_class_name = "#{formatter.to_s.gsub(/(^|_)([a-z])/) { |m| $~[2].upcase }}Formatter"
    elsif formatter.is_a?(String)
      formatter_class_name = formatter
    end
    if formatter_class_name
      formatter = Formatter.const_get(formatter_class_name)
    end

    if formatter.is_a?(Class)
      formatter = formatter.new(*args)
    end

    Array(klass).each do |k|
      if k.instance_of?(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) ⇒ Object

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

Parameters:

  • severity (Integer, String, Symbol) —

    The severity of the message.

  • timestamp (Time) —

    The time the message was logged.

  • progname (String) —

    The name of the program logging the message.

  • msg (Object) —

    The message object to format.



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# File 'lib/lumberjack/formatter.rb', line 175

def call(severity, timestamp, progname, msg)
  "#{format(msg)}#{Lumberjack::LINE_SEPARATOR}"
end

#clear ⇒ self

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

Returns:

  • (self) —

    Returns itself so that clear statements can be chained together.



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# File 'lib/lumberjack/formatter.rb', line 149

def clear
  @class_formatters.clear
  @module_formatters.clear
  self
end

#format(message) ⇒ Object

Format a message object by applying all formatters attached to it.

Parameters:

  • message (Object) —

    The message object to format.

Returns:

  • (Object) —

    The formatted object.



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# File 'lib/lumberjack/formatter.rb', line 159

def format(message)
  formatter = formatter_for(message.class)
  if formatter&.respond_to?(:call)
    formatter.call(message)
  else
    message
  end
end

#remove(klass) ⇒ self

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.

Parameters:

  • klass (Class, Module, String, Array<Class, Module, String>) —

    The class or module to remove the formatters for.

Returns:

  • (self) —

    Returns itself so that remove statements can be chained together.



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# File 'lib/lumberjack/formatter.rb', line 134

def remove(klass)
  Array(klass).each do |k|
    if k.instance_of?(Module)
      @module_formatters.delete(k)
    else
      k = k.name if k.is_a?(Class)
      @class_formatters.delete(k)
    end
  end
  self
end