如何清除我的 Rails 文件缓存？答案

【问题标题】：How do I clear my Rails file cache?如何清除我的 Rails 文件缓存？
【发布时间】：2017-03-18 22:57:54
【问题描述】：

我在 Ubuntu 14.04 上运行 Rails 4.2.7。我编写了以下方法来帮助缓存一些数据（防止命中我的 PostGres 9.5 数据库）……

class Country < ActiveRecord::Base
  has_many :states

  def self.cached_find_by_iso(iso)
    Rails.cache.fetch("#{iso}") do
      find_by_iso(iso)
    end
  end

end

但是，即使在运行 rake tmp:cache:clear 并重新启动我的服务器后，我在尝试调用上述内容时仍会收到此错误……

Error during processing: Not a directory @ rb_file_s_rename - (/home/rails/myproject/tmp/cache/00020161104-1093-67j634, /home/rails/myproject/tmp/cache/001/000/)
/usr/local/rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/fileutils.rb:528:in `rename'
/usr/local/rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/fileutils.rb:528:in `block in mv'
/usr/local/rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/fileutils.rb:1571:in `block in fu_each_src_dest'
/usr/local/rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/fileutils.rb:1587:in `fu_each_src_dest0'
/usr/local/rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/fileutils.rb:1569:in `fu_each_src_dest'
/usr/local/rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/fileutils.rb:517:in `mv'
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-4.2.7.1/lib/active_support/core_ext/file/atomic.rb:36:in `atomic_write'
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-4.2.7.1/lib/active_support/cache/file_store.rb:83:in `write_entry'
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-4.2.7.1/lib/active_support/cache/strategy/local_cache.rb:115:in `write_entry'
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-4.2.7.1/lib/active_support/cache.rb:391:in `block in write'
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-4.2.7.1/lib/active_support/cache.rb:547:in `block in instrument'
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-4.2.7.1/lib/active_support/notifications.rb:166:in `instrument'
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-4.2.7.1/lib/active_support/cache.rb:547:in `instrument'
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-4.2.7.1/lib/active_support/cache.rb:389:in `write'
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-4.2.7.1/lib/active_support/cache.rb:588:in `save_block_result_to_cache'
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-4.2.7.1/lib/active_support/cache.rb:299:in `fetch'
/home/rails/myproject/app/models/country.rb:5:in `cached_find_by_iso'
/home/rails/myproject/app/services/all_events_guide_service.rb:84:in `block in process_page_data'
/usr/local/rvm/gems/ruby-2.3.0/gems/nokogiri-1.6.8.1/lib/nokogiri/xml/node_set.rb:187:in `block in each'
/usr/local/rvm/gems/ruby-2.3.0/gems/nokogiri-1.6.8.1/lib/nokogiri/xml/node_set.rb:186:in `upto'
/usr/local/rvm/gems/ruby-2.3.0/gems/nokogiri-1.6.8.1/lib/nokogiri/xml/node_set.rb:186:in `each'
/home/rails/myproject/app/services/all_events_guide_service.rb:45:in `process_page_data'
/home/rails/myproject/app/services/abstract_import_service.rb:83:in `process_my_object_data'
/home/rails/myproject/app/services/all_events_guide_my_object_finder_service.rb:103:in `block in process_my_object_link'
/usr/local/rvm/gems/ruby-2.3.0/gems/nokogiri-1.6.8.1/lib/nokogiri/xml/node_set.rb:187:in `block in each'
/usr/local/rvm/gems/ruby-2.3.0/gems/nokogiri-1.6.8.1/lib/nokogiri/xml/node_set.rb:186:in `upto'
/usr/local/rvm/gems/ruby-2.3.0/gems/nokogiri-1.6.8.1/lib/nokogiri/xml/node_set.rb:186:in `each'
/home/rails/myproject/app/services/all_events_guide_my_object_finder_service.rb:82:in `process_my_object_link'
/home/rails/myproject/app/services/abstract_my_object_finder_service.rb:29:in `block in process_data'
/home/rails/myproject/app/services/abstract_my_object_finder_service.rb:28:in `each'
/home/rails/myproject/app/services/abstract_my_object_finder_service.rb:28:in `process_data'
/home/rails/myproject/app/services/run_crawlers_service.rb:18:in `block in run_all_crawlers'
/usr/local/rvm/gems/ruby-2.3.0/gems/activerecord-4.2.7.1/lib/active_record/relation/delegation.rb:46:in `each'
/usr/local/rvm/gems/ruby-2.3.0/gems/activerecord-4.2.7.1/lib/active_record/relation/delegation.rb:46:in `each'
/home/rails/myproject/app/services/run_crawlers_service.rb:5:in `run_all_crawlers'
/home/rails/myproject/app/controllers/my_objects_controller.rb:170:in `block in import'

清除我的缓存并让我的缓存方法正常启动的正确方法是什么？

编辑：我得到了与 Deepak 的建议相同的上述错误，但这是他的回答的输出......

rails@mymachine:~/myproject$ rails console
Loading development environment (Rails 4.2.7.1)
2.3.0 :001 > Rails.cache.clear
 => ["/home/rails/myproject/tmp/cache/assets"] 
2.3.0 :002 > quit

编辑 2： 这是我的 config/environments.production.rb 文件。这是一个生产环境……

Rails.application.configure do
  # Settings specified here will take precedence over those in config/application.rb.

  # Code is not reloaded between requests.
  config.cache_classes = true

  # Eager load code on boot. This eager loads most of Rails and
  # your application in memory, allowing both threaded web servers
  # and those relying on copy on write to perform better.
  # Rake tasks automatically ignore this option for performance.
  config.eager_load = true

  # Full error reports are disabled and caching is turned on.
  config.consider_all_requests_local       = false
  config.action_controller.perform_caching = true

  # Enable Rack::Cache to put a simple HTTP cache in front of your application
  # Add `rack-cache` to your Gemfile before enabling this.
  # For large-scale production use, consider using a caching reverse proxy like
  # NGINX, varnish or squid.
  # config.action_dispatch.rack_cache = true

  # Disable serving static files from the `/public` folder by default since
  # Apache or NGINX already handles this.
  config.serve_static_files = ENV['RAILS_SERVE_STATIC_FILES'].present?

  # Compress JavaScripts and CSS.
  config.assets.js_compressor = :uglifier
  # config.assets.css_compressor = :sass

  # Do not fallback to assets pipeline if a precompiled asset is missed.
  config.assets.compile = false

  # Asset digests allow you to set far-future HTTP expiration dates on all assets,
  # yet still be able to expire them through the digest params.
  config.assets.digest = true

  # `config.assets.precompile` and `config.assets.version` have moved to config/initializers/assets.rb

  # Specifies the header that your server uses for sending files.
  # config.action_dispatch.x_sendfile_header = 'X-Sendfile' # for Apache
  # config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect' # for NGINX

  # Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies.
  # config.force_ssl = true

  # Use the lowest log level to ensure availability of diagnostic information
  # when problems arise.
  config.log_level = :debug

  # Prepend all log lines with the following tags.
  # config.log_tags = [ :subdomain, :uuid ]

  # Use a different logger for distributed setups.
  # config.logger = ActiveSupport::TaggedLogging.new(SyslogLogger.new)

  # Use a different cache store in production.
  # config.cache_store = :mem_cache_store

  # Enable serving of images, stylesheets, and JavaScripts from an asset server.
  # config.action_controller.asset_host = 'http://assets.example.com'

  # Enable locale fallbacks for I18n (makes lookups for any locale fall back to
  # the I18n.default_locale when a translation cannot be found).
  config.i18n.fallbacks = true

  # Send deprecation notices to registered listeners.
  config.active_support.deprecation = :notify

  # Use default logging formatter so that PID and timestamp are not suppressed.
  config.log_formatter = ::Logger::Formatter.new

  # Do not dump schema after migrations.
  config.active_record.dump_schema_after_migration = false

  config.serve_static_assets = true
  config.assets.compile = true
end

【问题讨论】：

一切都取决于您存储缓存的位置。检查配置文件并找到：config.cache_store，然后根据您的设置进行清理
我的应用程序中没有这样的设置。在我的 config/environments/proudtion.rb 文件中，该行被注释掉了，“# config.cache_store = :mem_cache_store”
Deepak 已回答您的问题
您可以尝试将iso 变量设置为integer 值吗？
你在说什么iso变量？

标签： ruby-on-rails ruby-on-rails-4 caching tmp

【解决方案1】：

在控制台中运行以下命令，而不是 rake tmp:cache:clear

Rails.cache.clear

这将从您正在使用的任何缓存存储中清除缓存

config.cache_store = :file_store
# or
config.cache_store = :mem_cache_store

【讨论】：

根据我对 numBar 的评论，我没有“config.cache_store”文件设置。但是，我编辑了我的问题以显示您的建议。运行编辑中详述的命令后，我仍然得到“不是目录@rb_file_s_rename”。
能否请您也从您的 development.rb 或 production.rb 中发布设置
当然，编辑我的问题以包含 config/enviornmetns/produciton.rb 文件（这是一个生产环境）
!!!!警告：Rails.cache.clear 不只是清除 RAILS 缓存键。如果你的缓存是 redis 并且你也在运行 sidekiq，那就告别所有计划的作业、作业历史记录等。

【解决方案2】：

您的应用程序似乎需要路径 tmp/cache/001/000/ 存在。而且，如您所见： https://github.com/rails/rails/blob/4-2-stable/railties/lib/rails/tasks/tmp.rake#L25-L30，任务rake tmp:cache:clear 删除了tmp/cache 的所有内容，包括001/000。我想一个快速的解决方案是在清除缓存后通过mkdir -p tmp/cache/001/000/ 在项目根目录中手动创建该路径。

您可以通过rails g task cache 将自定义任务添加到您的应用程序以自动执行此操作并编写如下内容：

namespace :cache do
  task :clear do
    FileUtils.rm_rf(Dir['tmp/cache/[^.]*'])
    `mkdir -p tmp/cache/001/000/`
  end
end

然后您可以调用您的自定义 rake cache:clear 并确保所需的路径存在。

【讨论】：