Module: SteppedService

Defined in:

lib/stepped_service/base.rb,
lib/stepped_service/errors.rb

Overview

Service class based on steps chain (see #steps), which can be successfull even with errors. If execution of step is successful, next step will be executed. Step can be marked as failed by calling #fail!. That will stop executing steps chain and return as #failed?. During processing, #errors can be added, but they will not stop the execution.

Example usage

class TeaMaker < SteppedService::Base
  attr_reader :tea_type, :bags_into_kettle
  def initialize(tea_type:, bags_into_kettle:)
    @tea_type = tea_type
    @bags_into_kettle = bags_into_kettle
  end

  def steps
    %i[get_water_into_kettle
      make_it_boil
      put_tea_bags_into_kettle
      wait_3mins
      pour_tea_into_cups
      add_sugar_to_caps]
  end

  private

  attr_accessor :teabags, :kettle, :cups

  def get_water_into_kettle
    self.kettle = find_kettle
    unless kettle
      errors.add(:kettle, "There is no kettle in kitchen!")
      fail!
    end
    fill_water_into(kettle)
  end

  def make_it_boil
    ...
  end

  def put_tea_bags_into_kettle
    self.teabags = get_teabags(tea_type, bags_into_kettle)
    if teabags.empty?
      errors.add(:teabags, "There is no #{bags_into_kettle} #{tea_type} tea teabags in storage," \
                           "  using fruit tea teabags.")
      self.teabags = get_teabags(:fruit, bags_into_kettle)
      if teabags.empty?
        errors.add(:teabags, "There is no #{bags_into_kettle} fruit tea teabags in storage either!")
        fail!
      end
    end
    insert(teabags, to: kettle)
  end

  ...

  def add_sugar_to_caps # last step should fill @result
     cups.each{ |c| c.insert(sugar_cube) }
     @result = cups
  end
end

calling

teamaker = TeaMaker.call(:black, 2)

will return instance of with:

• if there is no kettle :

  teamaker.failure? # => true
  teamaker.result # => nil
  teamaker.errors[:kettle] # => ["There is no kettle in kitchen!"]
  

• if there is no black tea but fruit was found:

  teamaker.success? # => true
  teamaker.result # => _cups with fruit tea_
  teamaker.errors[:teabags] # => ["There is no 2 :black tea teabags in storage, using fruit tea teabags."]
  

• if there is no black or fruit tea:

  teamaker.success? # => false
  teamaker.result # => nil
  teamaker.errors[:teabags] # => ["There is no 2 :black tea teabags in storage, using fruit tea teabags.",
                                  "There is no 2 fruit tea teabags in storage either!"]

• if all goes well:

  teamaker.success? # => true
  teamaker.result # => _cups with black tea_
  teamaker.errors # => {}
  

Defined Under Namespace

Classes: Base, Errors