Environments

1. There are three predefined environments: development , production and test .

2. Environments can be set through the RACK_ENV environment variable.

3. The default value is development
4. In the development environment all templates are reloaded between requests, and special not_found and error handlers display stack traces in your browser
5. In the production and test environments, templates are cached by default
6. To run different environments, set the RACK_ENV environment variable:

   RACK_ENV=production ruby my_app.rb
   

7. You can use predefined methods: development?, test? and production? to check the current environment setting:

   get '/' do
     if settings.development?
       "development!"
     else
       "not development!"
     end
   end