Phoenix-like `pipeline` plugin for Roda

roda_pipeline.rb

require 'bundler/inline'

gemfile(true) do
  gem 'roda'
  gem 'webrick'
end

class M1
  def initialize(app)
    @app = app
  end

  def call(env)
    puts 'M1'
    @app.call(env)
  end
end

class M2
  def initialize(app)
    @app = app
  end

  def call(env)
    puts 'M2'
    @app.call(env)
  end
end

class Roda
  module RodaPlugins
    module Pipeline
      module ClassMethods
        def pipeline(id, procs)
          opts[:pipelines] ||= {}
          opts[:pipelines][id] = [:itself.to_proc, *procs.reverse].reduce { |app, midleware| midleware.new(app) }
        end
      end

      module InstanceMethods
        def pipe_through(*pipelines)
          pipelines.reduce(env) do |acc, pipeline_id|
            acc = opts[:pipelines][pipeline_id].call(acc)
          end
        end
      end
    end
  end
end

class App < ::Roda
  plugin Roda::RodaPlugins::Pipeline

  pipeline(:api, [M1])
  pipeline(:web, [M1, M2])

  route do |routes|
    routes.root do
      'root'
    end

    routes.on('foo') do
      pipe_through(:api)
      'foo'
    end

    routes.on('bar') do
      pipe_through(:web)
      'bar'
    end
  end
end

Rack::Server.start(app: App)