Question

我有一个奇怪的情况，突然面临编译前的失败，老实说，由于某些原因，我无法看到这个问题。

我在这里添加了一个带有日志和参考文件的要点 https://gist.github.com/malagodia/8506722

令我困惑的是，我阅读了有关数据库连接的Heroku建议，并明确确保application.rb包含

config.assets.initialize_on_precompile = false

这是日志输出错误，完整登录要点

Running: rake assets:precompile
       rake aborted!
       undefined method `[]=' for nil:NilClass
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/config/initializers/database_connection.rb:7:in `block (2 levels) in <top (required)>'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/lazy_load_hooks.rb:38:in `instance_eval'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/lazy_load_hooks.rb:38:in `execute_hook'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/lazy_load_hooks.rb:28:in `block in on_load'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/lazy_load_hooks.rb:27:in `each'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/lazy_load_hooks.rb:27:in `on_load'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/config/initializers/database_connection.rb:5:in `block in <top (required)>'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/lazy_load_hooks.rb:36:in `call'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/lazy_load_hooks.rb:36:in `execute_hook'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/lazy_load_hooks.rb:45:in `block in run_load_hooks'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/lazy_load_hooks.rb:44:in `each'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/lazy_load_hooks.rb:44:in `run_load_hooks'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/railties-4.0.2/lib/rails/application/finisher.rb:62:in `block in <module:Finisher>'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/railties-4.0.2/lib/rails/initializable.rb:30:in `instance_exec'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/railties-4.0.2/lib/rails/initializable.rb:30:in `run'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/railties-4.0.2/lib/rails/initializable.rb:55:in `block in run_initializers'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/railties-4.0.2/lib/rails/initializable.rb:54:in `run_initializers'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/railties-4.0.2/lib/rails/application.rb:215:in `initialize!'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/railties-4.0.2/lib/rails/railtie/configurable.rb:30:in `method_missing'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/config/environment.rb:5:in `<top (required)>'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/dependencies.rb:229:in `require'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/dependencies.rb:229:in `block in require'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/dependencies.rb:214:in `load_dependency'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/dependencies.rb:229:in `require'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/railties-4.0.2/lib/rails/application.rb:189:in `require_environment!'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/railties-4.0.2/lib/rails/application.rb:250:in `block in run_tasks_blocks'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/sprockets-rails-2.0.1/lib/sprockets/rails/task.rb:54:in `block (2 levels) in define'
       Tasks: TOP => environment
       (See full trace by running task with --trace)  !  !     Precompiling assets failed.  !

 !     Push rejected, failed to compile Ruby app

追踪追踪heroku指出     〜$ rake assets：precompile --trace
    **调用资产：预编译（first_time）
    **调用资产：环境（first_time）
    **执行资产：环境
    **调用环境（first_time）
    **执行环境
    **执行资产：预编译

Answer 1

从Rails 4升级到4.1时，我最近遇到了这个问题。

为了解决这个问题，我刚删除了文件database_connection.rb。我有这个文件是因为Heroku的文章是Concurrency and Database Connections in Ruby with ActiveRecord。

我希望它有所帮助！

Answer 2

我相信您的config值为nil，因为您预编译资产时数据库（或环境中的任何其他内容）不可用，因此您应该尽力避免任何事情与该阶段的数据库相关。情况描述为here。

他们描述的解决方案只是“不要那样做”：

“一旦隔离了错误，就必须通过不依赖于环境变量和数据库在预编译时出现来修复错误。”

Answer 3

我的情况，我忘了更新application.css的扩展名以包含.scss。所以，我猜测，sprockets试图编译一个不存在的.scss文件;因此没有错误。

我通过运行＆＃34; RAILS_ENV =生产包exec rake资产来识别错误：预编译＆＃34;在本地但在生产环境中编译我的资产（根据Heroku文档：https://devcenter.heroku.com/articles/rails-asset-pipeline）并查看最后几行输出（输出比将整个应用程序推送到Heroku更清洁，更快）：

NoMethodError：未定义的方法`[]＆＃39;为零：NilClass （在/other_stuff/my_app/app/assets/stylesheets/application.css中）

我注意到了.css扩展名并添加了.scss来修复错误。

Rails 4 Heroku资产：预编译失败

3 个答案: