簡單使用EM :: Synchrony＃sync會導致“根光纖” FiberError —我的錯？

Question

這個程序

require 'em-synchrony' ## v1.0.0                                                                                                                               
require 'em-hiredis'   ## v0.1.0                                                                                                                               

module EventMachine
  module Hiredis
    class Client

      def self.connect(host = 'localhost', port = 6379)
        conn = new(host, port)
        EM::Synchrony.sync conn.connect
    conn
      end

      alias :old_method_missing :method_missing
      def method_missing(sym, *args)
        EM::Synchrony.sync old_method_missing(sym, *args)
      end
    end
  end
end

EventMachine.synchrony do
  redis = EM::Hiredis.connect

  redis.set('foo', 'bar')
  puts redis.get('foo')

  EM.stop
end

這樣死

$ ruby /tmp/reddy.rb 
/home/blt/.rvm/gems/ruby-1.9.3-p0/gems/em-synchrony-1.0.0/lib/em-synchrony.rb:58:in `yield': can't yield from root fiber (FiberError)
    from /home/blt/.rvm/gems/ruby-1.9.3-p0/gems/em-synchrony-1.0.0/lib/em-synchrony.rb:58:in `sync'
    from /tmp/reddy.rb:16:in `method_missing'
    from /home/blt/.rvm/gems/ruby-1.9.3-p0/gems/em-hiredis-0.1.0/lib/em-hiredis/client.rb:119:in `select'
    from /home/blt/.rvm/gems/ruby-1.9.3-p0/gems/em-hiredis-0.1.0/lib/em-hiredis/client.rb:38:in `block in connect'
    from /home/blt/.rvm/gems/ruby-1.9.3-p0/gems/em-hiredis-0.1.0/lib/em-hiredis/event_emitter.rb:8:in `call'
    from /home/blt/.rvm/gems/ruby-1.9.3-p0/gems/em-hiredis-0.1.0/lib/em-hiredis/event_emitter.rb:8:in `block in emit'
    from /home/blt/.rvm/gems/ruby-1.9.3-p0/gems/em-hiredis-0.1.0/lib/em-hiredis/event_emitter.rb:8:in `each'
    from /home/blt/.rvm/gems/ruby-1.9.3-p0/gems/em-hiredis-0.1.0/lib/em-hiredis/event_emitter.rb:8:in `emit'
    from /home/blt/.rvm/gems/ruby-1.9.3-p0/gems/em-hiredis-0.1.0/lib/em-hiredis/connection.rb:15:in `connection_completed'
    from /home/blt/.rvm/gems/ruby-1.9.3-p0/gems/eventmachine-1.0.0.beta.4/lib/eventmachine.rb:179:in `run_machine'
    from /home/blt/.rvm/gems/ruby-1.9.3-p0/gems/eventmachine-1.0.0.beta.4/lib/eventmachine.rb:179:in `run'
    from /home/blt/.rvm/gems/ruby-1.9.3-p0/gems/em-synchrony-1.0.0/lib/em-synchrony.rb:27:in `synchrony'
    from /tmp/reddy.rb:22:in `<main>'

我覺得這很令人困惑。 為什么它不起作用，我是否有錯？ 如果是這樣，我該怎么做？ 除非我掩蓋了某些內容，否則根據em-synchrony自述文件，這是潔凈的。

Answer 1

我認為，如果您找到正確的em-hiredis版本並嘗試猴子補丁，那么您的代碼就可以工作，這是依賴項松散的問題之一。

這是一個完全正常的代碼，但是基於em-synchrony的master分支：

的Gemfile：

source :rubygems

gem 'em-synchrony', :git => "git://github.com/igrigorik/em-synchrony.git"
gem 'em-hiredis', '~> 0.1.0'

test.rb：

require 'rubygems'
require 'bundler/setup'

require 'em-synchrony'
require 'em-synchrony/em-hiredis'

EventMachine.synchrony do
  redis = EM::Hiredis.connect

  redis.set('foo', 'bar')
  puts redis.get('foo')

  EM.stop
end

然后運行：

$ bundle
$ ruby test.rb

猴子修補是修補寶石的一種固有的有缺陷的方法，除非您確保使用了修補的寶石的確切版本，這是同步應該強制執行或至少要檢測到的。