Using Mongoid, MongoHQ, and Heroku

-

I recently tried to set up mongoid with a free mongohq account on heroku... This info is accurate as of 28 Feb, 2012.

For the impatient (I just want to make it work)

mongoid.yml

production:
  uri: <%= ENV['MONGOLAB_URI'] %>

Gemfile

gem 'bson', '1.3.1'
gem 'bson_ext', '1.3.1'
gem 'mongoid', '2.0.2'

For those who want more detail (I have a similar problem, how do I troubleshoot

To determine heroku environment variables, do this:

$ heroku config
and the results should contain a line like what follows: 
...
MONGOLAB_URI        => mongodb://heroku_app928349384:lkfjgoierheourhgoeurhgoeuh@ds031087.mongolab.com:31087/heroku_appapp928349384
...

The important thing to note is what the left hand line says. Around the internet (like here on SO they will incorrectly name the ENV as MONGOHQ_URI. So then update mongoid.yml like this:

Additionally, it appears that different versions of mongoid only work with certain versions of mongodb. I started by digging around on google to find versions that seemed to be compatible.

Stack trace with wrong URI: 
production:
  uri: <%= ENV['MONGOLAB_URI'] %>

Will yield something like

2012-02-28T12:49:46+00:00 app[web.1]: /app/.bundle/gems/ruby/1.9.1/gems/mongo-1.3.1/lib/mongo/connection.rb:518:in `connect': Failed to connect to a master node at localhost:27017 (Mongo::ConnectionFailure)
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/mongo-1.3.1/lib/mongo/connection.rb:656:in `setup'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/mongo-1.3.1/lib/mongo/connection.rb:101:in `initialize'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/mongo-1.3.1/lib/mongo/connection.rb:152:in `new'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/mongo-1.3.1/lib/mongo/connection.rb:152:in `from_uri'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/mongoid-2.0.2/lib/mongoid/config/database.rb:86:in `master'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/mongoid-2.0.2/lib/mongoid/config/database.rb:19:in `configure'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/mongoid-2.0.2/lib/mongoid/config.rb:114:in `from_hash'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/mongoid-2.0.2/lib/mongoid/config.rb:342:in `configure_databases'
2012-02-28T12:49:46+00:00 app[web.1]:  from (eval):2:in `from_hash'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/mongoid-2.0.2/lib/mongoid/railtie.rb:64:in `block in <class:Railtie>'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/initializable.rb:25:in `instance_exec'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/initializable.rb:25:in `run'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/initializable.rb:50:in `block in run_initializers'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/initializable.rb:49:in `run_initializers'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/initializable.rb:49:in `each'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/application.rb:134:in `initialize!'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/application.rb:77:in `method_missing'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/config/environment.rb:5:in `<top (required)>'
2012-02-28T12:49:46+00:00 app[web.1]:  from <internal:lib/rubygems/custom_require>:29:in `require'
2012-02-28T12:49:46+00:00 app[web.1]:  from <internal:lib/rubygems/custom_require>:29:in `require'
2012-02-28T12:49:46+00:00 app[web.1]:  from config.ru:3:in `block (3 levels) in <main>'
2012-02-28T12:49:46+00:00 app[web.1]:  from /home/heroku_rack/heroku.ru:23:in `eval'
2012-02-28T12:49:46+00:00 app[web.1]:  from /home/heroku_rack/heroku.ru:23:in `block (3 levels) in <main>'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/rack-1.2.5/lib/rack/builder.rb:46:in `instance_eval'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/rack-1.2.5/lib/rack/builder.rb:46:in `initialize'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/rack-1.2.5/lib/rack/builder.rb:63:in `new'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/rack-1.2.5/lib/rack/builder.rb:63:in `map'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/rack-1.2.5/lib/rack/builder.rb:46:in `initialize'
2012-02-28T12:49:46+00:00 app[web.1]:  from /home/heroku_rack/heroku.ru:18:in `block (2 levels) in <main>'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/rack-1.2.5/lib/rack/builder.rb:46:in `instance_eval'
2012-02-28T12:49:46+00:00 app[web.1]:  from /home/heroku_rack/heroku.ru:11:in `block in <main>'
2012-02-28T12:49:46+00:00 app[web.1]:  from /home/heroku_rack/heroku.ru:11:in `new'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/rack-1.2.5/lib/rack/builder.rb:46:in `instance_eval'
2012-02-28T12:49:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/rack-1.2.5/lib/rack/builder.rb:46:in `initialize'
2012-02-28T12:49:46+00:00 app[web.1]:  from /home/heroku_rack/heroku.ru:1:in `new'
2012-02-28T12:49:46+00:00 app[web.1]:  from /home/heroku_rack/heroku.ru:1:in `<main>'
2012-02-28T12:49:46+00:00 app[web.1]:  from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/thin-1.2.6/lib/rack/adapter/loader.rb:36:in `eval'
2012-02-28T12:49:46+00:00 app[web.1]:  from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/thin-1.2.6/lib/rack/adapter/loader.rb:36:in `load'
2012-02-28T12:49:46+00:00 app[web.1]:  from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/thin-1.2.6/lib/thin/controllers/controller.rb:175:in `load_rackup_config'
2012-02-28T12:49:46+00:00 app[web.1]:  from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/thin-1.2.6/lib/thin/controllers/controller.rb:65:in `start'
2012-02-28T12:49:46+00:00 app[web.1]:  from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/thin-1.2.6/lib/thin/runner.rb:177:in `run_command'
2012-02-28T12:49:46+00:00 app[web.1]:  from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/thin-1.2.6/lib/thin/runner.

2012-02-28T12:49:46+00:00 app[web.1]:  from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/thin-1.2.6/bin/thin:6:in `<top (required)>'
2012-02-28T12:49:46+00:00 app[web.1]:  from /usr/ruby1.9.2/bin/thin:19:in `load'
2012-02-28T12:49:46+00:00 app[web.1]:  from /usr/ruby1.9.2/bin/thin:19:in `<main>'
2012-02-28T12:49:47+00:00 heroku[web.1]: Process exited with status 1
2012-02-28T12:49:47+00:00 heroku[web.1]: State changed from starting to crashed

Stack trace with wrong version of mongo/mongoid/bson : 

Starting process with command `thin -p 4644 -e production -R /home/heroku_rack/heroku.ru start`
2012-02-27T22:50:46+00:00 app[web.1]: /app/app/models/expression.rb:2:in `<class:Expression>': uninitialized constant Expression::Mongoid (NameError)
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/app/models/expression.rb:1:in `<top (required)>'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/engine.rb:138:in `block (2 levels) in eager_load!'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/engine.rb:137:in `each'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/engine.rb:137:in `block in eager_load!'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/engine.rb:135:in `eager_load!'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/engine.rb:135:in `each'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/application.rb:108:in `eager_load!'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/application/finisher.rb:41:in `block in <module:Finisher>'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/initializable.rb:25:in `instance_exec'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/initializable.rb:25:in `run'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/initializable.rb:50:in `block in run_initializers'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/initializable.rb:49:in `each'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/initializable.rb:49:in `run_initializers'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/application.rb:134:in `initialize!'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/railties-3.0.8/lib/rails/application.rb:77:in `method_missing'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/config/environment.rb:5:in `<top (required)>'
2012-02-27T22:50:46+00:00 app[web.1]:  from <internal:lib/rubygems/custom_require>:29:in `require'
2012-02-27T22:50:46+00:00 app[web.1]:  from /home/heroku_rack/heroku.ru:23:in `eval'
2012-02-27T22:50:46+00:00 app[web.1]:  from <internal:lib/rubygems/custom_require>:29:in `require'
2012-02-27T22:50:46+00:00 app[web.1]:  from config.ru:3:in `block (3 levels) in <main>'
2012-02-27T22:50:46+00:00 app[web.1]:  from /home/heroku_rack/heroku.ru:23:in `block (3 levels) in <main>'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/rack-1.2.5/lib/rack/builder.rb:46:in `instance_eval'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/rack-1.2.5/lib/rack/builder.rb:46:in `initialize'
2012-02-27T22:50:46+00:00 app[web.1]:  from /home/heroku_rack/heroku.ru:18:in `block (2 levels) in <main>'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/rack-1.2.5/lib/rack/builder.rb:46:in `initialize'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/rack-1.2.5/lib/rack/builder.rb:63:in `new'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/rack-1.2.5/lib/rack/builder.rb:63:in `map'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/rack-1.2.5/lib/rack/builder.rb:46:in `instance_eval'
2012-02-27T22:50:46+00:00 app[web.1]:  from /home/heroku_rack/heroku.ru:11:in `new'
2012-02-27T22:50:46+00:00 app[web.1]:  from /home/heroku_rack/heroku.ru:11:in `block in <main>'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/rack-1.2.5/lib/rack/builder.rb:46:in `instance_eval'
2012-02-27T22:50:46+00:00 app[web.1]:  from /app/.bundle/gems/ruby/1.9.1/gems/rack-1.2.5/lib/rack/builder.rb:46:in `initialize'
2012-02-27T22:50:46+00:00 app[web.1]:  from /home/heroku_rack/heroku.ru:1:in `new'
2012-02-27T22:50:46+00:00 app[web.1]:  from /home/heroku_rack/heroku.ru:1:in `<main>'
2012-02-27T22:50:46+00:00 app[web.1]:  from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/thin-1.2.6/lib/rack/adapter/loader.rb:36:in `eval'
2012-02-27T22:50:46+00:00 app[web.1]:  from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/thin-1.2.6/lib/thin/controllers/controller.rb:175:in `load_rackup_config'
2012-02-27T22:50:46+00:00 app[web.1]:  from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/thin-1.2.6/lib/rack/adapter/loader.rb:36:in `load'
2012-02-27T22:50:46+00:00 app[web.1]:  from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/thin-1.2.6/lib/thin/controllers/controller.rb:65:in `start'
2012-02-27T22:50:46+00:00 app[web.1]:  from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/thin-1.2.6/lib/thin/runner.rb:177:in `run_command'
2012-02-27T22:50:46+00:00 app[web.1]:  from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/thin-1.2.6/bin/thin:6:in `<top (required)>'
2012-02-27T22:50:46+00:00 app[web.1]:  from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/thin-1.2.6/lib/thin/runner.rb:143:in `run!'
2012-02-27T22:50:46+00:00 app[web.1]:  from /usr/ruby1.9.2/bin/thin:19:in `load'
2012-02-27T22:50:46+00:00 app[web.1]:  from /usr/ruby1.9.2/bin/thin:19:in `<main>'
2012-02-27T22:50:47+00:00 heroku[web.1]: Process exited with status 1
2012-02-27T22:50:47+00:00 heroku[web.1]: State changed from starting to crashed
2012-02-27T22:50:48+00:00 heroku[router]: Error H10 (App crashed) -> POST newsfilter.heroku.com/_heroku/console dyno= queue= wait= service= status=503 bytes=

I apologize in advance for the poor formatting on this post...

Comments

Gosha Arinich said…
I have an app with the most recent mongoid, which uses MongoLab, and runs on heroku just okay. Haven't experienced what you said.
February 28, 2012 at 11:10 AM
Mike Mainguy said…
Interesting, which heroku stack are you using?
February 28, 2012 at 4:36 PM
Mike Mainguy said…
And could you post the relevant parts of your Gemfile.lock?
February 28, 2012 at 4:38 PM
Post a Comment

Popular posts from this blog

Please use ANSI-92 SQL Join Syntax

-
Image
Way back in 1992, a standard was published for SQL. In it, the syntax for specifying joins in SQL Database was finally standardized. This was a good thing because (for folks who've been doing this a while), trying to decode the vagaries of how various Databases handled outer joins could drive you bonkers yielding different results depending on the parse order of things in the from and where clauses. Unfortunately, some DBMS vendors took a while to adopt this standard (Oracle didn't support it until 2001), but at this point if you're using a major RDBMS and NOT using it, you're probably mired in a tradition or habit that bears changing. As an example of what I'm describing, here are some examples of what I mean. Old School (no standard syntax + implementation and evaluation of predicates varied by vendor [and query]): select * from customer, order where customer.customer = order.customerid ANSI way (agreed to standard, predicate evaluation has some rules
Read more

the myth of asynchronous JDBC

-
Image
I keep seeing people (especially in the scala/typesafe world) posting about async jdbc libraries. STOP IT! Under the current APIs, async JDBC belongs in a realm with Unicorns, Tiger Squirrels, and 8' spiders. While you might be able to move the blocking operations and queue requests and keep your "main" worker threads from blocking, jdbc is synchronous. At some point, somewhere, there's going to be a thread blocking waiting for a response. It's frustrating to see so many folks hyping this and muddying the waters. Unless you write your own client for a dbms and have a dbms that can multiplex calls over a single connection (or using some other strategy to enable this capability) db access is going to block. It's not impossible to make the calls completely async, but nobody's built it yet. Yes, I know ajdbc is taking a stab at this capability, but even IT uses a thread pool for the blocking calls (be default). Someday we'll have async databa
Read more

The difference between Scalability, Performance, Efficiency, and Concurrency explained

-
I thought I'd give some explanation of the difference between scalability, performance, Efficiency, and concurrency. To make things more accessible (and because I'm watching a cooking show on TV) I'm going to use a baking metaphor to help explain the differences. In our case, the system in question is baking cookies for consumers. Scalability, is how well something responds to adding more resources. If we can double our capacity by doubling the number of resources, we've got linear scalability. In our baking example, if we add more ingredients, we can scale to a larger number of cookies. To contrast with our other metrics, this doesn't actually increase the performance of creating a single cookie (they still take 10 minutes to bake), and the efficiency is the same (we just have more capacity). We also cannot bake more cookies in a fixed time period, but over a larger time period we can produce more cookies. Performance is how fast something can get done, u
Read more