Minirails

Run example rails app from single file

Inspired by The Smallest Rails App, I wanted to easily try various concepts inside rails apps without having to deal with all that bloat from standard rails directory structure.

I went even further, not only reducing full rails app into single file (that has already been done) but to reducing a set of rails apps into single file 😎

More seriously, you can now create whole microservice architecture within a singe file and somebody else will be able to grasp it all and execute it locally. Or you can easily make a single file app and post it to StackOverflow (and people can actually run this code)

Just think about it. Proof of Concepts. Asking questions. Explaining concepts.

Installation

$ gem install minirails

Basic usage

Create a file myapp.rb with the following content

# myapp.rb
define do |app|
  class MainController < ActionController::Base
    def index
      render text: "Hello"
    end
  end

  app.routes.draw do
    get "/", to: "main#index"
  end
end

then run

$ minirails myapp.rb

and that's it - you now have fully functional rails app running on port 5000!

Advanced usage

Multiple apps

You can run multiple applications from singe file

# file: multiple.rb
# usage: $ minirails multiple.rb
define "one" do |app|
  app.routes.draw do
    get "/", to: proc {|*| [200, {}, "Hello".lines] }
  end
end

define "two" do |app|
  app.routes.draw do
    get "/", to: proc {|*| [200, {}, "World".lines] }
  end
end

They will be run on ports 5000 and 5100 (and 5200 etc.)

Database setup

You can also use full ActiveRecord capabilities. The database (specified with ENV["DATABASE_URL"]) will be recreated (drop & create & migrate) on every run

# file: database.rb
# usage: $ minirails database.rb
define "source" do |app|
  # Configuration
  ENV["DATABASE_URL"] = "postgresql://localhost/minirails_test"

  # Migrations
  class Migrations < ActiveRecord::Migration
    def change
      create_table :users do |t|
        t.string :name
        t.string :email
      end

      # Seeds
      User.create! [
        {name: "Jon", email: "jon@example.com"},
        {name: "Hodor", email: "hodor@example.com"}
      ]
    end
  end


  # Models
  class User < ActiveRecord::Base
  end

  # Controllers
  class UsersController < ActionController::Base
    def index
      render json: User.all
    end
  end

  # Routes
  app.routes.draw do
    resources :users
  end
end

Non-rails apps

You can start any rack compatible web app inside define block or even generic worker process (sidekiq, clock, whatever) by specifying :type option.

# file: types.rb
# usage: $ minirails types.rb

# this is rails app
define "rails" do |app|
  app.routes.draw do
    get "/", to: proc {|*| [200, {}, "Hello from Rails".lines] }
  end
end

# with type: :rack you need to return Rack-compatible app
define "rack", type: :rack do
  proc {|*| [200, {}, "Hello from Rack".lines] }
end

# with type: :blank you can run anything
define "worker", type: :blank do
  loop do
    $stderr.puts "Hello from worker"
    sleep 1
  end
end

Running worker with Rails env loaded

define "my-rails-app" do |app|
  app.routes.draw do
    get "/", to: proc {|*| [200, {}, "Hello from Rails".lines] }
  end
end

# you can use :initialize option to load rails (or some rack)
# before loading worker code (similar to `rake environment`)
define "worker", type: :blank, initialize: "my-rails-app" do
  loop do
    Rails.logger.debug "Hello from worker with Rails env"
    sleep 1
  end
end

FAQ

How to speed up loading?

Run $ minirails --fast and then use bin/minirails myapp.rb instead

Contributing

Fork it ( https://github.com/teamon/minirails/fork )
Create your feature branch (git checkout -b my-new-feature)
Commit your changes (git commit -am 'Add some feature')
Push to the branch (git push origin my-new-feature)
Create a new Pull Request

minirails

Development

Runtime