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Introduction

Teckel provides a common interface for wrapping your ruby business logic into,
with enforced input, output and error data structures.

The two main components are Operations and Chains.

Motivation

Working with Interactor, Trailblazer's Operation and Dry-rb's Transaction and probably a hand full of inconsistent "service objects", I missed a system that:

  1. provides and enforces well defined input, output and error structures
  2. makes chaining multiple operation easy and reliable
  3. is easy to debug

About Code Samples

Code samples are tested using byexamples.

They all use a common base setup to have some fake objects to work with:

# frozen_string_literal: true

require "English"
require "dry-types"
require "dry-struct"

Warning[:experimental] = false if Warning.respond_to? :[]

module Types
  include Dry.Types()
end

module FakeDB
  Rollback = Class.new(RuntimeError)

  def self.transaction
    yield
  rescue Rollback # standard:disable Lint/UselessRescue
    # doing rollback ...
    raise
  end
end

class User
  def initialize(name:, age:)
    @name, @age = name, age
  end
  attr_reader :name, :age

  def save
    !underage?
  end

  def errors
    underage? ? [{age: "underage"}] : nil
  end

  def underage?
    @age <= 18
  end
end