Workflows

Workflows is an attempt to create multiple-step services. each step of the workflow is service by itself that has a run method. it can fail or succeed and the status of the step will change to :fail or :ok respectively. each service in this model has two types of output. one that is called state and another that is called output. state will be passed to the next step of the workflow, so if there are objects that need to be passed between the steps, they should be kept in state. outputs are not passed between the steps and are only holding the output value of each executed step of the workflow.

Add this line to your application's Gemfile:

gem 'workflows'

And then execute:

$ bundle

Or install it yourself as:

$ gem install workflows

You can find more examples in the example directory of the gem.

If you have a workflow such as the following:

class BarbieMakerFlow
  include Workflows


  has_flow [
    {
      name: 'design',
      service: Design,
      args: [:gender, :specification]
    },
    {
      name: 'make',
      service: Make,
      args: [:outfit]
    }
  ]

end

class Design
  include Workflows::StepService

  def run
    set_state(
      barbie: Barbie.new(args.gender, args.specification)
    )
  end
end

class Make
  include Workflows::StepService

  def run
    barbie = get_state[:barbie]
    msg = barbie.dress_up(args.outfit)

    set_output(msg)
    set_state(barbie: barbie)
  end
end

class Barbie
  attr_reader :gender,
              :specification,
              :outfit

  def initialize(gender, specification)
    @gender = gender
    @specification = specification
  end

  def dress_up(outfit)
    @outfit = outfit
    "#{@gender} #{@specification} barbie is wearing a #{outfit}"
  end
end

you can now run your flow by providing input arguments for each step:

bmf = BarbieMakerFlow.new(
  design: { gender: 'female', specification: 'Software Engineer' },
  make: { outfit: 'white shirt and navy shorts' }
)

bmf.run  #=> runs the flow with provided inputs
bmf.status #=> [:ok, :ok] | [:ok, :fail] | [:fail, :fail]
bmf.output #=> ['output of design', 'output of make']
bmf.state #=> Barbie.new(gender: 'female',
specification: ....)

After checking out the repo, run bin/setup to install dependencies. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/sjahandideh/workflows. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

The gem is available as open source under the terms of the MIT License.