Combustion Engine

CombustionEngine.md

For those of you who might be using your engine as a git submodule in a bigger project, here is what I've settled on (riffed a bit from pat/combustion#13 (comment)). I will admit that a bit of the final result is due to trail/error. For instance, I don't really know what the task :environment block does, but I know when I run rake db:migrate, it executes that block, and thus requires additional requires.

If someone else has a clearer understanding of how everything is fitting together, please let me know and I'll update

We do not need to modify db paths in the Rakefile because we've set those up as initializers in the engine.rb so that the main app pulls migrations and schema.rb from the core project. (Bonus points for loading FactoryBot factories to be reused in the main app!)

engine.rb

module Core
  class Engine < ::Rails::Engine
    initializer :append_paths do |app|
      app.config.paths['db'] = config.paths['db'].expanded
      app.config.paths['db/migrate'] = config.paths['db/migrate'].expanded

      # So we can use core factories in the main app
      if defined?(FactoryBot)
        FactoryBot.definition_file_paths.unshift(Core.root.join('spec', 'factories'))
      end
    end
  end
end

Rakefile

# === boot ===

begin
  require "bundler/setup"
rescue LoadError
  puts 'You must `gem install bundler` and `bundle install` to run rake tasks'
end

# === application ===

require "rails"
require "combustion"
require "active_record/railtie"

Bundler.require :default, Rails.env

Combustion.path = '/'
Combustion::Application.configure_for_combustion

# === Rakefile ===

task :environment do
  require 'dotenv/rails'
  require "action_mailer/railtie"
end

require "rspec/core/rake_task"

Combustion::Application.load_tasks

task(:default).clear
task(:spec).clear

RSpec::Core::RakeTask.new(:spec) do |t|
  t.verbose = false
end

task default: [:spec]