如何关闭 Rack 应用程序中的异常？

Question

I'm ready to deploy a RackServerPages application but can't seem to find a way to disable exceptions ie, the one rendered by Rack::ShowExceptions.

Thanks!

Answer 1

Set the RACK_ENV environment variable to deployment .

Technically, setting ENV['RACK_ENV'] to anything besides development will disable the exceptions. Rack::ShowExceptions middleware is included by default when rack is running in the default development environment .

For Rails apps, set ENV['RACK_ENV'] to deployment , making sure you also set ENV['RAILS_ENV'] to the correct value for your environment ( production , development , etc.). If ENV['RAILS_ENV'] is not set, the Rails app will fallback to ENV['RACK_ENV'] and Rails will complain about an unknown deployment environment.

If you use unicorn , you can alternatively use -E deployment to set ENV['RACK_ENV'] to deployment .

Answer 2

I have several hour unpleasant experience of unsuccessfully trying to disable Rack::ShowExceptions but in the end I discovered I don't need to do that.

In production this is turned off (when you try to curl -XINVALID -k https://my-production-app.com it will return just blank screen).

But this won't solve the issue if you need to disable this in custom (eg "staging") environment (still showing the rack trace code.)

tested on Rails 3.2.21

on Rails 4.0.12 this works for my production and custom "staging" environment

Answer 3

As ENV['RACK_ENV'] is the universal Rack solution, Rack-based framework often have higher level solutions.

Examples

Sinatra

In the config.rb it is possible to define :environment . It is also possible to use ENV['APP_ENV'] .

configure do
  set :environment, :production
end

Roda

There is an error handling plugin .

class App < Roda
  plugin :error_handler do |e|
    'Oh No!'
  end
end

And also an environment plugin.

class App < Roda
  plugin :environments

  self.environment = :production
end