ruby on rails - Heroku upload-Precompiling assets failed

Question

I need help. When trying to upload my app to heroku, I get this error, anyone know why? A few was wrong. thanks

       Using rake (10.1.0)
       ...
       Using tlsmail (0.0.1)
       Using uglifier (2.1.2)
       Your bundle is complete! It was installed into ./vendor/bundle
-----> Writing config/database.yml to read from DATABASE_URL
-----> Preparing app for Rails asset pipeline
       Running: rake assets:precompile
       /tmp/build_e8889be5-168c-49ed-81e7-b71061fc82ee/vendor/bundle/ruby/1.9.1/gems/tlsmail-0.0.1/lib/net/smtp.rb:806: warning: already initialized constant SMTPSession
       ...
       /tmp/build_e8889be5-168c-49ed-81e7-b71061fc82ee/vendor/bundle/ruby/1.9.1/gems/tlsmail-0.0.1/lib/net/pop.rb:702: warning: already initialized constant APOPSession
       DEPRECATION WARNING: You have Rails 2.3-style plugins in vendor/plugins! Support for these plugins will be removed in Rails 4.0. Move them out and bundle them in your Gemfile, or fold them in to your app as lib/myplugin/* and config/initializers/myplugin.rb. See the release notes for more on this: http://weblog.rubyonrails.org/2012/1/4/rails-3-2-0-rc2-has-been-released. (called from <top (required)> at /tmp/build_e8889be5-168c-49ed-81e7-b71061fc82ee/Rakefile:7)
       ...
       rake aborted!
       could not connect to server: Connection refused
       Is the server running on host "127.0.0.1" and accepting
       TCP/IP connections on port 5432?
       /tmp/build_e8889be5-168c-49ed-81e7-b71061fc82ee/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.12/lib/active_record/connection_adapters/postgresql_adapter.rb:1208:in `initialize'
       /tmp/build_e8889be5-168c-49ed-81e7-b71061fc82ee/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.12/lib/active_record/connection_adapters/postgresql_adapter.rb:1208:in `new'
       ...
       /tmp/build_e8889be5-168c-49ed-81e7-b71061fc82ee/vendor/bundle/ruby/1.9.1/gems/actionpack-3.2.12/lib/sprockets/assets.rake:29:in `block (2 levels) in <top (required)>'
       Tasks: TOP => environment
       (See full trace by running task with --trace)
 !
 !     Precompiling assets failed.

Answer 1

From the Heroku docs:

This means that your app is attempting to connect to the database as part of rake assets:precompile. Because the config vars are not present in the environment, we use a placeholder DATABASE_URL to satisfy Rails.

To resolve this issue, ensure that the following line appears in your config/application.rb:

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

Once added, commit your change and redeploy to Heroku – your assets should compile without your app attempting to connect to the database, which should resolve the error you're witnessing.

UPDATE:

Line 46 of your stacktrace includes the following message: Devise.secret_key was not set.

According to the author of Devise, José Valim, this issue can be resolved in the following manner:

Please add the following to your Devise initializer:

config.secret_key = '-- secret key --'

Alternatively, the following solution seems to have worked for a number of users:

I went to my routes.rb file and commented out the line devise_for :installs

Then I went back and reran rails generate devise:install. If that doesn't work, use the previous version of devise by editing your Gemfile's reference to Devise like this: gem 'devise', '3.0.3' and then follow the steps i mentioned above.