我正在尝试为我在 Ubuntu 服务器上运行的 Rails 3.1 应用程序设置守护进程。就像这样简单的事情:
require File.expand_path('../../config/environment', __FILE__)
require 'rubygems'
require 'daemons'
Daemons.run_proc('my_script') do
loop do
puts BlogPost.count
sleep(5)
end
end
但是当我到达 BlogPost.count
时,出现以下错误:
/usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/connection_adapters/mysql2_adapter.rb:283:in `query': Mysql2::Error: MySQL server has gone away: SHOW FIELDS FROM `blog_posts` (ActiveRecord::StatementInvalid)
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/connection_adapters/mysql2_adapter.rb:283:in `execute'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract_adapter.rb:244:in `log'
from /usr/lib/ruby/gems/1.8/gems/activesupport-3.1.0/lib/active_support/notifications/instrumenter.rb:21:in `instrument'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract_adapter.rb:239:in `log'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/connection_adapters/mysql2_adapter.rb:283:in `execute'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/connection_adapters/mysql2_adapter.rb:473:in `columns'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:95:in `initialize'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:185:in `with_connection'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:92:in `initialize'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/base.rb:706:in `call'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/base.rb:706:in `default'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/base.rb:706:in `[]'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/base.rb:706:in `columns'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/base.rb:722:in `column_names'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/relation/calculations.rb:192:in `aggregate_column'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/relation/calculations.rb:213:in `execute_simple_calculation'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/relation/calculations.rb:187:in `perform_calculation'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/relation/calculations.rb:155:in `calculate'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/relation/calculations.rb:58:in `count'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/base.rb:445:in `__send__'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.1.0/lib/active_record/base.rb:445:in `count'
from script/background_job_processor_control.rb:22
知道为什么我的脚本无法连接到 MySQL 吗?如果我将 BlogPost.count
代码放在 Daemons.run_proc
之前,我就可以很好地连接到 MySQL。
------------ 编辑:已解决! --------------
对于任何对解决方案感到好奇的人,我必须做三件事才能让它发挥作用:
- 在启动/停止我的守护程序时包含
bundle exec
:RAILS_ENV=production bundle exec myscript.rb start
。 - 此时我不再收到 MySQL2 错误,但开始收到记录器错误。解决方案是在
run_proc
block 中添加以下代码:ActiveRecord::Base.logger = ActiveSupport::BufferedLogger.new('/path/to/log/file.log')
- 然后我遇到了第三个错误,解决方案是在
run_proc
block 中而不是在脚本的前面要求 Rails 环境。
我的最终脚本如下所示:
require 'rubygems'
require 'daemons'
Daemons.run_proc('my_script') do
require File.expand_path('../../config/environment', __FILE__)
ActiveRecord::Base.logger = ActiveSupport::BufferedLogger.new('/path/to/log/file.log')
loop do
puts BlogPost.count
sleep(5)
end
end
最佳答案
要为脚本正确预加载 Rails 环境(依赖项),请按如下方式启动它:
bundle exec my_script_ctl start
关于mysql - Rails 3.1 + Daemons gem 不允许我访问我的数据库,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/9749449/