Question

Where does the concept of ‘development mode’ come from when using ruby + webrick + sinatra?

require 'sinatra'
require 'sinatra/reloader'

get '/test' do
  development?.to_s
end

When I run the above app by ‘ruby test.rb -p 3000’ http://localhost:3000/test returns “true” … but why does it return true? Is development mode a ruby, webrick, rack or sinatra concept? Also, is this functionality documented anywhere in particular in a non-rails specific manner? I’m finding many people reference the concept of development mode, but I’ve been surprised by how hard it has been to find relevant information … maybe I’m just not google-ing the right keywords …

Answer 1

Sinatra’s source code (base.rb) shows these 3 definitions:

def development?; environment == :development end
def production?;  environment == :production  end
def test?;        environment == :test        end

So those true/false methods are based on the set environment. Sinatra defaults to run in development mode unless you tell it otherwise (when you start a Sinatra app, you’ll see something like

== Sinatra/1.2.6 has taken the stage on 4567 for **development** with backup from WEBrick".

To tell it to run in production, you would do this:

ruby test.rb -p 3000 -e production