module InjectedLogger

Constants

DefaultInjectionBlockMissing
Error
InUse
UnsupportedLevels
VERSION

Public Class Methods

after_injection(on: nil, &blk) click to toggle source

# File lib/injectedlogger/logger.rb, line 23
def self.after_injection(on: nil, &blk)
  on = blk.binding.eval 'self' if on.nil?
  logger[on].after_hook = blk
end

inject(*args, on:, **options) click to toggle source

# File lib/injectedlogger/logger.rb, line 15
def self.inject(*args, on:, **options)
  logger[on].inject(*args, **options)
end

inject!(*args, on:, **options) click to toggle source

# File lib/injectedlogger/logger.rb, line 19
def self.inject!(*args, on:, **options)
  logger[on].inject!(*args, **options)
end

injected?(on:) click to toggle source

# File lib/injectedlogger/logger.rb, line 11
def self.injected?(on:)
  logger[on].injected?
end

logger_known(as:, refers_to:) click to toggle source

# File lib/injectedlogger/logger.rb, line 28
def self.logger_known(as:, refers_to:)
  logger[as] = logger[refers_to]
end

use(*required, on: nil, as: nil, method_name: :logger, &blk) click to toggle source

inject a default logger in case no one has set one for you:

module MyLogger

InjectedLogger.use :info, :debug, :invented do
  require 'logger'
  # parameters are inject() params, none is required, but if
  # logger is not present, a default one will be used.
  { logger: Logger.new(STDERR), prefix: '[mylogger]', ... }
end

end

class WantsLogging

include MyLogger

def some_method_needing_logging
  logger.info 'some info'
end

def some_method_with_invented_level_logging
  logger.invented do
    'some invented logging'
  end
end

end

This will only run the block passed to inject IFF there was no logger set up to be used by InjectedLogger, and it will only happen the first time the logger method is called, so that it does not 'require' anything if it is not needed. :)

# File lib/injectedlogger.rb, line 36
def self.use(*required, on: nil, as: nil, method_name: :logger, &blk)
  if on.nil?
    raise InjectedLogger::DefaultInjectionBlockMissing if blk.nil?
    on = blk.binding.eval 'self'
  end
  on = on.singleton_class unless on.is_a? Module
  InjectedLogger.logger_known as: as, refers_to: on unless as.nil?
  targets = [on]
  targets << on.singleton_class unless on.singleton_class?
  targets.each do |target|
    [:inject, :inject!].each do |m|
      target.define_singleton_method m do |*args, **options|
      options.merge! on: on
      InjectedLogger.public_send m, *args, **options
      end
    end
  end
  prelogger = proc do
    # avoid recursion if someone calls logger in the block
    targets.each do |target|
      target.send :remove_method, method_name
    end
    unless InjectedLogger.injected? on: on
      args = blk ? blk.call : nil
      InjectedLogger.inject_logger args, required, on: on
    end
    thislogger = InjectedLogger.send(:logger).[](on)
    required.uniq!
    required -= thislogger.level_info[:supported]
    unless required.empty?
      thislogger.add_levels(*required)
      required -= thislogger.level_info[:supported]
      raise InjectedLogger::UnsupportedLevels.new(required) unless required.empty?
    end
    targets.each do |target|
      target.send :define_method, method_name do
        thislogger
      end
    end
    thislogger.after_hook.call(thislogger) if thislogger.after_hook
    thislogger.send :ready
    thislogger
  end
  targets.each do |target|
    target.send :define_method, method_name, prelogger
  end
end

Private Class Methods

default_logger() click to toggle source

# File lib/injectedlogger.rb, line 86
def self.default_logger
  require 'logger'
  { logger: ::Logger.new(STDERR) }
end

inject_logger(args, required, **options) click to toggle source

# File lib/injectedlogger.rb, line 91
def self.inject_logger(args, required, **options)
  args ||= {}
  args = default_logger.merge(args) unless args.has_key? :logger
  logger = args.delete :logger
  unless required.empty?
    args[:levels] ||= []
    args[:levels].push(required).flatten!
    args[:levels].uniq!
  end
  args.merge!(**options)
  InjectedLogger.inject(logger, **args)
end

logger() click to toggle source

# File lib/injectedlogger/logger.rb, line 6
def self.logger
  @logger ||= Hash.new { |h, k| h[k] = Logger.new }
end