Rails 4 - NO manifest.json after assets precompile on production server

Question

Here is the app/assets/ for a Rails 4.2 app.

There are 3 bootstraps js and css files. After deploying to production (ubuntu 12.1), assets precompile was done on server (deployed under suburi):

RAILS_ENV=production bundle exec rake assets:precompile RAILS_RELATIVE_URL_ROOT=/mysuburi

Here is the production.rb:

  config.cache_classes = true
  config.eager_load = true
  config.consider_all_requests_local       = false
  config.action_controller.perform_caching = true
  config.serve_static_files = false #ENV['RAILS_SERVE_STATIC_FILES'].present?
  config.assets.compress = true
  config.assets.js_compressor = :uglifier
  config.assets.compile = false
  config.assets.digest = true
  config.log_level = :debug
  config.i18n.fallbacks = true
  config.active_support.deprecation = :notify
  config.log_formatter = ::Logger::Formatter.new
  config.active_record.dump_schema_after_migration = false

Here is the head of application.css.scss:

@import "bootstrap.min.css";
@import "bootstrap-theme.min.css";

@import "simple_form.css.scss";
@import "user_menus.css.scss";

In application.js, it has:

//= require bootstrap.min

Here is the output of ls for public/assets/ on production server:

application-05cf37813d76c2bd659271403789374cc118f1a4e616ec220969577b79ff6514.css
application-375b4b5d8fc285716f4fdca966aa960912efe8292242df8f1a60b99d5caa4b02.js
authentify
banquet_coursex
banquetx
biz_workflowx
commonx
glyphicons-halflings-regular-5d234508037dc13a419ef6ce48f3fc73dbb477f1a162c052b872182b494e626e.svg
glyphicons-halflings-regular-bd18efd3efd70fec8ad09611a20cdbf99440b2c1d40085c29be036f891d65358.ttf
glyphicons-halflings-regular-f495f34e4f177cf0115af995bbbfeb3fcabc88502876e76fc51a4ab439bc8431.eot
glyphicons-halflings-regular-fc969dc1c6ff531abcf368089dcbaf5775133b0626ff56b52301a059fc0f9e1e.woff
jquery-ui
searchx
state_machine_logx
user_manualx
user_menus-7c46e17f4172c2a954eeaf85e80b4e030d1ed0fb3927288bbe07eeb4fb8cbfc5.css

By comparing with other Rails app, it is missing manifest.json under /assets. We tried various config options in config/environment/production.rb with no avail. The only option works on production server is live compilation of config.assets.compile = true (not recommended). What is wrong with our code to cause assets precompile failing?

UPDATE: we have re-built the Rails app from ground up and the assets problem remains the same. This assets precompile issue may have nothing to do with setup in config/production.rb' and 'config/initializers/aseets.rb as we suspect. Rolling back version of bundler and rake did not help. The same bootstrap css and js files have been used in another Rails 4.2 app running on the same production server without the problem.

Answer 1

If you're using sprockets 3.x, the manifest file is now named .sprockets-manifest-md5hash.json, it is stated in the Upgrading Guide