Dry-system component example using gems

components.rb

# foo/lib/foo.rb
require 'dry/system'
require 'foo/version'

module Foo
  Dry::System.register_provider(
    :foo,
    boot_path: Pathname(__dir__).join('foo/components').realpath
  )
end

# foo/lib/foo/components/logger.rb
Dry::System.register_component(:logger, provider: :foo) do
  init do
    require 'logger'
  end

  start do
    register(:logger, Logger.new($stdout))
  end
end

# Main application Gemfile
gem 'foo', path: './lib/foo'

# Main application system container myapp/system/myapp/container.rb
require 'dry/system/container'

module Myapp
  class Container < Dry::System::Container
    boot :logger, from: :foo
    
    configure do |config|
      config.name :myapp
      ...
    end
    
    load_paths!('lib')
  end
  
  Container.finalize!
end

# Which allows in console to do:
> require 'myapp'
true
> Myapp::Container[:logger].info "hello world!"
I, [2018-01-04T16:35:36.531424 #7230]  INFO -- : hello world!
 => true