我尝试使用Capistrano部署我的Rails应用程序，并收到以下错误：
NoMethodError: undefined method `to_h' for nil:NilClass
这是堆栈跟踪，看起来它可能是一个Sprockets问题，但我无法弄清楚原因：
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-es6-0.9.0/lib/sprockets/es6.rb:14:in `configuration_hash'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-es6-0.9.0/lib/sprockets/es6.rb:40:in `configuration_hash'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-es6-0.9.0/lib/sprockets/es6.rb:44:in `initialize'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-es6-0.9.0/lib/sprockets/es6.rb:21:in `new'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-es6-0.9.0/lib/sprockets/es6.rb:21:in `instance'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-es6-0.9.0/lib/sprockets/es6.rb:34:in `call'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/processor_utils.rb:75:in `call_processor'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/processor_utils.rb:57:in `block in call_processors'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/processor_utils.rb:56:in `reverse_each'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/processor_utils.rb:56:in `call_processors'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/loader.rb:134:in `load_from_unloaded'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/loader.rb:60:in `block in load'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/loader.rb:318:in `fetch_asset_from_dependency_cache'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/loader.rb:44:in `load'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/cached_environment.rb:20:in `block in initialize'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/cached_environment.rb:47:in `yield'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/cached_environment.rb:47:in `default'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/cached_environment.rb:47:in `load'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/bundle.rb:23:in `block in call'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/utils.rb:183:in `dfs'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/bundle.rb:24:in `call'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/processor_utils.rb:75:in `call_processor'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/processor_utils.rb:57:in `block in call_processors'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/processor_utils.rb:56:in `reverse_each'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/processor_utils.rb:56:in `call_processors'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/loader.rb:134:in `load_from_unloaded'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/loader.rb:60:in `block in load'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/loader.rb:318:in `fetch_asset_from_dependency_cache'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/loader.rb:44:in `load'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/cached_environment.rb:20:in `block in initialize'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/cached_environment.rb:47:in `yield'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/cached_environment.rb:47:in `default'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/cached_environment.rb:47:in `load'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/base.rb:66:in `find_asset'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/base.rb:73:in `find_all_linked_assets'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/manifest.rb:142:in `block in find'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/legacy.rb:114:in `block (2 levels) in logical_paths'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/path_utils.rb:225:in `block in stat_tree'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/path_utils.rb:209:in `block in stat_directory'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/path_utils.rb:206:in `each'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/path_utils.rb:206:in `stat_directory'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/path_utils.rb:224:in `stat_tree'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/legacy.rb:105:in `each'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/legacy.rb:105:in `block in logical_paths'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/legacy.rb:104:in `each'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/legacy.rb:104:in `logical_paths'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/manifest.rb:140:in `find'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/sprockets/manifest.rb:168:in `compile'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-rails-2.3.3/lib/sprockets/rails/task.rb:70:in `block (3 levels) in define'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-3.5.2/lib/rake/sprocketstask.rb:147:in `with_logger'
/var/www/paperless_office/shared/bundle/ruby/1.9.1/gems/sprockets-rails-2.3.3/lib/sprockets/rails/task.rb:69:in `block (2 levels) in define'
Tasks: TOP => assets:precompile
这是我的本地环境：
OSX 10.11.3
Ruby 2.1.3p242
Rails 4.1.0
Rake 10.3.2
Sprockets-Rails 2.3.3
Capistrano 3.4.0
这是我的生产环境：
Centos 5
ruby 2.1.3p242 (managed by rbenv)
我目前安装的宝石是：
bigdecimal (1.2.4)
bundler (1.11.2)
io-console (0.4.2)
json (1.8.1)
minitest (4.7.5)
psych (2.0.5)
rake (10.1.0)
rdoc (4.1.0)
test-unit (2.1.3.0)
我能够跑：
gem install bundler
但是，如果我跑：
gem install rails
我明白了：
ERROR: While executing gem ... (Gem::RemoteFetcher::FetchError)
bad response Service Unavailable 503 (https://api.rubygems.org/api/v1/dependencies?gems=rack)
这与我最初的问题有关吗？
答案 0 :(得分：0)
对于遇到这种情况的人来说，由于@ DavidK-J发布的链接指向了正确的方向，问题得以解决。我需要使用rbenv的设置更新cap文件，如下所示：
Capfile
require 'capistrano/rbenv'
deploy.rb
set :rbenv_type, :system
set :rbenv_path, '~/.rbenv'
set :rbenv_ruby, "2.1.3"
set :rbenv_prefix, "RBENV_ROOT=#{fetch(:rbenv_path)} RBENV_VERSION=#{fetch(:rbenv_ruby)} #{fetch(:rbenv_path)}/bin/rbenv exec"
set :rbenv_map_bins, %w{rake gem bundle ruby rails}
set :rbenv_roles, :all
然后，我必须使用rbenv的路径更新乘客的配置，在我的情况下是：
~/.rbenv
HTH别人。
保