Mongoid 3 + Heroku (MongoHQ) cause Moped::Errors::OperationFailure

Question

With Rails 3, after upgrading from Mongoid 2.x to Mongoid 3.x, my Heroku + MongoHQ setup stopped working. Funny thing is, that my development & test frameworks and my whole

Answer 1

You will need to use Ruby 1.9.3. See Mongoid documentation here and Heroku documentation here on how to use 1.9.3.

I was also getting similar errors, and I changed my gemfile to include ruby '1.9.3' and everything worked as expected again.

Edit: @herb pointed out that you need the latest version of bundler for this to work (gem install bundler --pre). Otherwise, ruby '1.9.3' in your Gemfile will not work.

Answer 2

As a workaround, hardcoding the uri from heroku config seems to do the trick.

ex:

production:
  sessions:
    default:
      uri: "mongodb://heroku:xxxx@domain.mongohq.com:000/appyyyy"
      options:
        skip_version_check: true
        safe: true

I'm guessing the nilclass error was because <%= ENV['MONGOHQ_URL'] %> was returning nil

Answer 3

Try adding an "options" area to the default session and add "skip_version_check: true" as one of the options.

Jason MongoHQ