Can't start Mongoid with Sinatra - ruby

Question

I'm trying to get started with Mongoid in a Sinatra app, but it looks like I'm running into dependency issues. If it helps, I'm on a Macbook Pro using RVM and running Ruby 1.9.3.
Here are the errors I'm getting after running $ ruby config.ru:
/Users/duncanmalashock/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1/rubygems/specification.rb:1637:in `raise_if_conflicts': Unable to activate mongoid-3.0.23, because activemodel-4.0.0 conflicts with activemodel (~> 3.1) (Gem::LoadError)
from /Users/duncanmalashock/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1/rubygems/specification.rb:746:in `activate'
from /Users/duncanmalashock/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1/rubygems.rb:212:in `rescue in try_activate'
from /Users/duncanmalashock/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1/rubygems.rb:209:in `try_activate'
from /Users/duncanmalashock/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1/rubygems/custom_require.rb:59:in `rescue in require'
from /Users/duncanmalashock/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1/rubygems/custom_require.rb:35:in `require'
from /Users/duncanmalashock/Penumbra/penumbra.rb:4:in `<top (required)>'
from /Users/duncanmalashock/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
from /Users/duncanmalashock/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
from config.ru:2:in `<main>'
Can anyone help?
Here are the files involved:
mongoid.yml:
development:
sessions:
default:
database: mongoid
hosts:
- localhost:27017
config.ru:
require 'sinatra'
require './penumbra'
run Sinatra::Application
Gemfile:
source :rubygems
source :rubyforge
# Thin Server
gem 'thin'
# Sinatra
gem 'sinatra'
gem 'sinatra-contrib', :require => 'sinatra/multi_route'
gem 'sinatra-partial', :require => 'sinatra/partial'
gem 'sinatra-reloader'
# MongoDB
gem "mongoid"
# Shopify
gem 'shopify_api'
penumbra.rb:
require 'sinatra'
require 'shopify_api'
require 'mongo'
require 'mongoid'
require 'json'
require "sinatra/reloader" if development?
Mongoid.load!("./mongoid.yml", :production)
def isactivepage(link_name)
if (link_name == #page_name)
return ' activelink'
else return ''
end
end
get '/' do
#page_name = "Home"
erb :"pages/index"
end
get '/about' do
#page_name = "About"
erb :"pages/about"
end
After running $ bundle exec rackup:
/Users/duncanmalashock/.rvm/gems/ruby-1.9.3-p448/gems/mongoid-1.0.6/lib/mongoid.rb:68:in `method_missing': undefined method `load!' for #<Mongoid::Config:0x007fc0838cb1d0> (NoMethodError)
from /Users/duncanmalashock/Penumbra/penumbra.rb:9:in `<top (required)>'
from /Users/duncanmalashock/Penumbra/config.ru:2:in `require'
from /Users/duncanmalashock/Penumbra/config.ru:2:in `block in <main>'
from /Users/duncanmalashock/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.5.2/lib/rack/builder.rb:55:in `instance_eval'
from /Users/duncanmalashock/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.5.2/lib/rack/builder.rb:55:in `initialize'
from /Users/duncanmalashock/Penumbra/config.ru:in `new'
from /Users/duncanmalashock/Penumbra/config.ru:in `<main>'
from /Users/duncanmalashock/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.5.2/lib/rack/builder.rb:49:in `eval'
from /Users/duncanmalashock/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.5.2/lib/rack/builder.rb:49:in `new_from_string'
from /Users/duncanmalashock/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.5.2/lib/rack/builder.rb:40:in `parse_file'
from /Users/duncanmalashock/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.5.2/lib/rack/server.rb:277:in `build_app_and_options_from_config'
from /Users/duncanmalashock/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.5.2/lib/rack/server.rb:199:in `app'
from /Users/duncanmalashock/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.5.2/lib/rack/server.rb:314:in `wrapped_app'
from /Users/duncanmalashock/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.5.2/lib/rack/server.rb:250:in `start'
from /Users/duncanmalashock/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.5.2/lib/rack/server.rb:141:in `start'
from /Users/duncanmalashock/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.5.2/bin/rackup:4:in `<top (required)>'
from /Users/duncanmalashock/.rvm/gems/ruby-1.9.3-p448/bin/rackup:23:in `load'
from /Users/duncanmalashock/.rvm/gems/ruby-1.9.3-p448/bin/rackup:23:in `<main>'

Answer 1

You have a Gemfile, but you’re not starting your app using Bundler, and that’s why you have the conflict.
The current version of shopify_api (3.0.3) has a dependency on activemodel via activeresource with the version requirements set to >=3.0.0. On your system you have Rails 4 installed, so activemodel 4.0 is loaded.
The current version of mongoid also has a dependency on activemodel, but this time the version requirement is ~> 3.2.
These two version requirements are not compatible, so you get the error activemodel-4.0.0 conflicts with activemodel (~> 3.1).
To fix it, simply use Bundler to start your app. You say you are running with $ ruby config.ru but this isn’t the correct way to use a config.ru (you would get errors later even if you fixed your dependency issues). You should use rackup. In this case you should run:
$ bundle exec rackup