我尝试了几种方法来使用Capistrano v3部署到我的服务器，但失败了，并出现以下错误；我尝试过在本地预编译，但失败了。
DEBUG [4ec78ee3] Command: cd /var/www/html/webapp/releases/20140101221937 && bundle exec rake assets:precompile RAILS_ENV=production
DEBUG [4ec78ee3] /usr/local/bin/ruby /var/www/html/webapp/shared/bundle/ruby/1.9.1/bin/rake assets:precompile:all RAILS_ENV=production RAILS_GROUPS=assets
DEBUG [4ec78ee3] rake aborted!
DEBUG [4ec78ee3] undefined method `fetch' for false:FalseClass
我的部署文件如下所示；
SSHKit.config.command_map[:rake] = "bundle exec rake"
namespace :deploy do
desc 'Restart application'
task :restart do
on roles(:app), in: :sequence, wait: 5 do
# Your restart mechanism here, for example:
execute :touch, release_path.join('tmp/restart.txt')
end
end
after :restart, :clear_cache do
on roles(:web), in: :groups, limit: 3, wait: 10 do
# Here we can do anything such as:
within release_path do
execute :rake, 'cache:clear'
end
end
end
after :finishing, 'deploy:cleanup'
end
这是一个详细的痕迹；
INFO [4ec78ee3] Running bundle exec rake assets:precompile RAILS_ENV=production on 208.68.39.56
DEBUG [4ec78ee3] Command: cd /var/www/html/webapp/releases/20140101221937 && bundle exec rake assets:precompile RAILS_ENV=production
DEBUG [4ec78ee3] /usr/local/bin/ruby /var/www/html/webapp/shared/bundle/ruby/1.9.1/bin/rake assets:precompile:all RAILS_ENV=production RAILS_GROUPS=assets
DEBUG [4ec78ee3] rake aborted!
DEBUG [4ec78ee3] undefined method `fetch' for false:FalseClass
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_specification.rb:35:in `resolve_string_connection'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_specification.rb:25:in `spec'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_specification.rb:130:in `establish_connection'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/activerecord-3.2.13/lib/active_record/railtie.rb:82:in `block (2 levels) in <class:Railtie>'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.13/lib/active_support/lazy_load_hooks.rb:36:in `instance_eval'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.13/lib/active_support/lazy_load_hooks.rb:36:in `execute_hook'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.13/lib/active_support/lazy_load_hooks.rb:26:in `block in on_load'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.13/lib/active_support/lazy_load_hooks.rb:25:in `each'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.13/lib/active_support/lazy_load_hooks.rb:25:in `on_load'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/activerecord-3.2.13/lib/active_record/railtie.rb:74:in `block in <class:Railtie>'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/railties-3.2.13/lib/rails/initializable.rb:30:in `instance_exec'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/railties-3.2.13/lib/rails/initializable.rb:30:in `run'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/railties-3.2.13/lib/rails/initializable.rb:55:in `block in run_initializers'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/railties-3.2.13/lib/rails/initializable.rb:54:in `each'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/railties-3.2.13/lib/rails/initializable.rb:54:in `run_initializers'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/railties-3.2.13/lib/rails/application.rb:136:in `initialize!'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/railties-3.2.13/lib/rails/railtie/configurable.rb:30:in `method_missing'
DEBUG [4ec78ee3] /var/www/html/webapp/releases/20140101221937/config/environment.rb:5:in `<top (required)>'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:251:in `require'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:251:in `block in require'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:236:in `load_dependency'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:251:in `require'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/railties-3.2.13/lib/rails/application.rb:103:in `require_environment!'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/railties-3.2.13/lib/rails/application.rb:297:in `block (2 levels) in initialize_tasks'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/actionpack-3.2.13/lib/sprockets/assets.rake:93:in `block (2 levels) in <top (required)>'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/actionpack-3.2.13/lib/sprockets/assets.rake:60:in `block (3 levels) in <top (required)>'
DEBUG [4ec78ee3] Tasks: TOP => environment
DEBUG [4ec78ee3] (See full trace by running task with --trace)
DEBUG [4ec78ee3] rake aborted!
DEBUG [4ec78ee3] Command failed with status (1): [/usr/local/bin/ruby /var/www/html/webapp/s...]
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/actionpack-3.2.13/lib/sprockets/assets.rake:12:in `ruby_rake_task'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/actionpack-3.2.13/lib/sprockets/assets.rake:21:in `invoke_or_reboot_rake_task'
DEBUG [4ec78ee3] /var/www/html/webapp/shared/bundle/ruby/1.9.1/gems/actionpack-3.2.13/lib/sprockets/assets.rake:29:in `block (2 levels) in <top (required)>'
DEBUG [4ec78ee3] Tasks: TOP => assets:precompile
DEBUG [4ec78ee3] (See full trace by running task with --trace)
我已经运行了cap production deploy:compile_assets
得到了这个；上限中止！
if test ! -d /var/www/html/webapp/current; then echo "Directory does not exist '/var/www/html/webapp/current'" 1>&2; false; fi stdout: Nothing written
if test ! -d /var/www/html/webapp/current; then echo "Directory does not exist '/var/www/html/webapp/current'" 1>&2; false; fi stderr: Nothing written
记住，它仍然是一个空文件。
这不是一个完整的答案，但却是故障排除的第一步。
首先，转到服务器，运行与Capistrano运行的命令完全相同的命令，以确保您可以重现完全相同的错误。这就把Capistrano排除在外了，现在这个bug变成了Rails和它的配置
以下是引发错误的行：
https://github.com/rails/rails/blob/v3.2.13/activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb#L35
错误消息告诉我们configurations是false，但代码希望它是响应fetch的某个对象(可能是一个散列)。问题是该ActiveRecord::Base::ConnectionSpecification::Resolver中的@configurations实例变量被错误地设置为false。你知道为什么会发生这种事吗？我会检查所有与数据库连接有关的配置文件，并确保它们看起来正常
如果这没有帮助，下一步是找出为什么该变量被设置为false。好吧，如果我们在堆栈跟踪的下面看两行，我们可以看到这个Resolver对象是如何创建和使用的：
https://github.com/rails/rails/blob/v3.2.13/activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb#L129-130
该方法只是调用ActiveRecord::Base.configurations并将其传递给Resolver对象。所以现在的问题变成了ActiveRecord::Base.configurations是如何被设置为false的？
编辑1:
以下是ActiveRecord::Base.configurations:的文档和代码
https://github.com/rails/rails/blob/v3.2.13/activerecord/lib/active_record/base.rb#L341-369
听起来ActiveRecord::Base.configurations应该来自您的database.yml文件。您应该转到服务器，仔细查看database.yml文件，看看它是否以某种方式被读取为false。你应该把那个文件张贴在这里。