如何让Rails.cache（内存缓存）与Puma一起使用？

I'm using Rails 5.1. I have application-wide memory_store caching happening with Rails. This is set up in my config/environments/development.rb file

我正在使用Rails 5.1。我在Rails中发生了应用程序范围的memory_store缓存。这是在我的config / environments / development.rb文件中设置的

  £ Enable/disable caching. By default caching is disabled.
  if Rails.root.join('tmp/caching-dev.txt').exist?
    config.action_controller.perform_caching = true

    config.cache_store = :memory_store
    config.public_file_server.headers = {
      'Cache-Control' => 'public, max-age=172800'
    }
  else
    config.action_controller.perform_caching = true
    config.cache_store = :memory_store
  end

This allows me to do things like

这让我可以做的事情

      Rails.cache.fetch(cache_key) do
        msg_data
      end

in one part of my application (a web socket) and access that data in another part of my application (a controller). However, what I'm noticing is that if I start my Rails server with puma running (e.g. include the below file at config/puma.rb) ...

在我的应用程序的一部分(Web套接字)并访问我的应用程序的另一部分(控制器)中的数据。但是,我注意到的是,如果我用puma运行启动我的Rails服务器(例如在config / puma.rb中包含以下文件)...

threads_count = ENV.fetch("RAILS_MAX_THREADS") { 5 }.to_i
threads threads_count, threads_count

£ Specifies the `port` that Puma will listen on to receive requests, default is 3000.
£
port        ENV.fetch("PORT") { 3000 }

£ Specifies the number of `workers` to boot in clustered mode.
£ Workers are forked webserver processes. If using threads and workers together
£ the concurrency of the application would be max `threads` * `workers`.
£ Workers do not work on JRuby or Windows (both of which do not support
£ processes).
£
workers ENV.fetch("WEB_CONCURRENCY") { 4 }

app_dir = File.expand_path("../..", __FILE__)
shared_dir = "£{app_dir}/shared"

£ Default to production
rails_env = ENV['RAILS_ENV'] || "production"
environment rails_env

£ Set up socket location
bind "unix://£{shared_dir}/sockets/puma.sock"

£ Logging
stdout_redirect "£{shared_dir}/log/puma.stdout.log", "£{shared_dir}/log/puma.stderr.log", true

£ Set master PID and state locations
pidfile "£{shared_dir}/pids/puma.pid"
state_path "£{shared_dir}/pids/puma.state"
activate_control_app





£ Use the `preload_app!` method when specifying a `workers` number.
£ This directive tells Puma to first boot the application and load code
£ before forking the application. This takes advantage of Copy On Write
£ process behavior so workers use less memory. If you use this option
£ you need to make sure to reconnect any threads in the `on_worker_boot`
£ block.
£
£ preload_app!

£ The code in the `on_worker_boot` will be called if you are using
£ clustered mode by specifying a number of `workers`. After each worker
£ process is booted this block will be run, if you are using `preload_app!`
£ option you will want to use this block to reconnect to any threads
£ or connections that may have been created at application boot, Ruby
£ cannot share connections between processes.
£
on_worker_boot do
  require "active_record"
  ActiveRecord::Base.connection.disconnect! rescue ActiveRecord::ConnectionNotEstablished
  ActiveRecord::Base.establish_connection(YAML.load_file("£{app_dir}/config/database.yml")[rails_env])
end

£ Allow puma to be restarted by `rails restart` command.
plugin :tmp_restart

In memory caching no longer works. In other words

内存缓存不再有效。换一种说法

Rails.cache.fetch(cache_key)

always returns nothing. I would like to have a multi-threaded puma environment (eventually) to gracefully handle many requests. However I'd also like my cache to work. How can I get them to both play together?

永远不会回报。我想有一个多线程的puma环境(最终)优雅地处理许多请求。但是我也喜欢我的缓存工作。我怎样才能让他们一起玩?

2 个解决方案

#1

You can't use memory_store with puma running in clustered mode (i.e. with multiple workers). It says so right here in the Rails guide. You can't share memory between separate processes, so this clearly stands to reason.

你不能使用memma在集群模式下运行的memory_store(即有多个worker)。它在Rails指南中就这么说了。你不能在不同的进程之间共享内存,所以这显然是有道理的。

If reducing puma workers down to 1 is not an option, then consider using Redis or Memcached instead. The documentation in the Rails guide is quite complete in this regard - you'll need to add a gem or two to your Gemfile, and update config.cache_store. You will need to install the relevant service on the box, or alternatively there are plenty of hosted service providers that will manage it for you (Heroku Redis, Redis To Go, Memcachier etc)

如果将puma worker减少到1不是一个选项,那么请考虑使用Redis或Memcached。在这方面,Rails指南中的文档非常完整 - 您需要在Gemfile中添加一个或两个gem,并更新config.cache_store。您需要在盒子上安装相关服务,或者有很多托管服务提供商将为您管理它(Heroku Redis,Redis To Go,Memcachier等)

#2

I don't know if you can - but don't do that in any case. Use a real cache service. memcached, for example.

我不知道你是否可以 - 但在任何情况下都不要这样做。使用真正的缓存服务。例如,memcached。

http://guides.rubyonrails.org/caching_with_rails.html

config.cache_store = :mem_cache_store, "localhost" # assuming you run memcached on localhost

And... That's about it.

而且......就是这样。

#1