Mongoid fails on ruby 1.9.3

Question

So I'm playing around with mongo stuffs. Created a new heroku app, added a mongolab option to it, but every mongoid method fails.

I googled around, and it looks like this issue was common with ruby prior to 1.9.3, but I'm running 1.9.3.

Here's the simplest failing sample:

require 'sinatra'
require 'mongoid'
require 'json'
require "sinatra/reloader" if development?

Mongoid.load!("mongoid.yml")

class Company
    include Mongoid::Document

    field :code, type: String
    field :sector, type: String
    field :share_id, type: Integer
    field :jse_code, type: Integer
end

get '/' do
    "Hello" 
end

get '/company' do
    Company.exists?
end

Wether I run this locally (against the mongolab db) or on heroku, I get the same kind of error:

12:22:33 web.1  | NoMethodError - undefined method `match' for nil:NilClass:
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/mongoid-3.0.13/lib/mongoid/sessions/mongo_uri.rb:49:in `initialize'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/mongoid-3.0.13/lib/mongoid/sessions/factory.rb:103:in `new'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/mongoid-3.0.13/lib/mongoid/sessions/factory.rb:103:in `parse'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/mongoid-3.0.13/lib/mongoid/sessions/factory.rb:62:in `create_session'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/mongoid-3.0.13/lib/mongoid/sessions/factory.rb:43:in `default'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/mongoid-3.0.13/lib/mongoid/sessions.rb:109:in `default'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/mongoid-3.0.13/lib/mongoid/sessions.rb:378:in `__session__'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/mongoid-3.0.13/lib/mongoid/sessions.rb:213:in `mongo_session'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/mongoid-3.0.13/lib/mongoid/sessions.rb:157:in `collection'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/mongoid-3.0.13/lib/mongoid/contextual/mongo.rb:216:in `initialize'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/mongoid-3.0.13/lib/mongoid/contextual.rb:47:in `new'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/mongoid-3.0.13/lib/mongoid/contextual.rb:47:in `create_context'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/mongoid-3.0.13/lib/mongoid/contextual.rb:30:in `context'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/mongoid-3.0.13/lib/mongoid/contextual.rb:20:in `rescue in exists?'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/mongoid-3.0.13/lib/mongoid/contextual.rb:18:in `exists?'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/mongoid-3.0.13/lib/mongoid/finders.rb:43:in `exists?'
12:22:33 web.1  |   app.rb:22:in `block in <main>'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:1265:in `call'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:1265:in `block in compile!'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:835:in `[]'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:835:in `block (3 levels) in route!'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:851:in `route_eval'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:835:in `block (2 levels) in route!'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:872:in `block in process_route'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:870:in `catch'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:870:in `process_route'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:834:in `block in route!'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:833:in `each'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:833:in `route!'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:936:in `dispatch!'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:769:in `block in call!'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:921:in `block in invoke'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:921:in `catch'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:921:in `invoke'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:769:in `call!'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:755:in `call'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/rack-protection-1.2.0/lib/rack/protection/xss_header.rb:22:in `call'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/rack-protection-1.2.0/lib/rack/protection/path_traversal.rb:16:in `call'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/rack-protection-1.2.0/lib/rack/protection/json_csrf.rb:17:in `call'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/rack-protection-1.2.0/lib/rack/protection/base.rb:47:in `call'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/rack-protection-1.2.0/lib/rack/protection/xss_header.rb:22:in `call'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/rack-1.4.1/lib/rack/logger.rb:15:in `call'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/rack-1.4.1/lib/rack/commonlogger.rb:20:in `call'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:136:in `call'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:129:in `call'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/rack-1.4.1/lib/rack/head.rb:9:in `call'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/rack-1.4.1/lib/rack/methodoverride.rb:21:in `call'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/showexceptions.rb:21:in `call'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:99:in `call'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:1389:in `block in call'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:1471:in `synchronize'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/sinatra-1.3.3/lib/sinatra/base.rb:1389:in `call'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/thin-1.5.0/lib/thin/connection.rb:81:in `block in pre_process'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/thin-1.5.0/lib/thin/connection.rb:79:in `catch'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/thin-1.5.0/lib/thin/connection.rb:79:in `pre_process'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/eventmachine-1.0.0/lib/eventmachine.rb:1037:in `call'
12:22:33 web.1  |   /Users/sdx/.rvm/gems/ruby-1.9.3-p327/gems/eventmachine-1.0.0/lib/eventmachine.rb:1037:in `block in spawn_threadpool'
12:22:33 web.1  | 127.0.0.1 - - [21/Nov/2012 12:22:33] "GET /__sinatra__/500.png HTTP/1.1" 200 31056 0.0062

What am I doing wrong ?

UPDATED here's my mongoid.yml:

production:
    sessions:
        default:
            uri: <%= ENV['MONGOLAB_URI'] %>
            options:
                skip_version_check: true
                safe: true
development:
    sessions:
        default:
            uri: <%= ENV['MONGOLAB_URI'] %>

Answer 1

Based on the stack trace it looks like the constructor for mongo_uri is being passed a null value. I'd check the following in your mongoid.yml:

• it's in the right place / the argument to load! points to the right place
• it's configured correctly
• if it refers to any environment variables (e.g. MONGOLAB_URI for the MongoLab Heroku add-on) that they're set in your environment

The relevant lines from mongo_uri.rb:49, where the exception is being thrown:

  # Create the new uri from the provided string.
  #
  # @example Create the new uri.
  #   MongoUri.new(uri)
  #
  # @param [ String ] string The uri string.
  #
  # @since 3.0.0
  def initialize(string)
    @match = string.match(URI)
  end

Answer 2

It has something to do with heroku not using environment variables when compiling assets.

Use this labs feature from heroku will help on this issue: https://devcenter.heroku.com/articles/labs-user-env-compile