Unicorn triggers mongoid error during assets precompile

Question

I have a rails app using Mongoid 3 running on Heroku. I\'ve just updated it to use Unicorn. When I try to deploy it to Heroku I get the following error :

Run         


        

Answer 1

As I recently had this problem with Rails 4.0 and config.assets.initialize_on_precompile = false no longer has any effect with Rails 4.0 I spoke with Heroku support and was told to use this labs feature:

heroku labs:enable user-env-compile

I wasn't able to get an answer as to why the user environment is necessary only with Unicorn but it seems to be a Unicorn specific problem of some sort or Thin does something that prevents the entire app from booting.

The whole thing seems odd to me and smells of a problem with the way assets are pre-compiled.

Answer 2

Rails 3:

Try to turn off app initialization when pre-compiling assets:

# config/application.rb
config.assets.initialize_on_precompile = false

The line should already be there commented out.