服务器处理请求后,无法使用control-Z挂起webrick

Question

在开发Rails 4.1.6项目时,我可以使用以下命令启动Webrick服务器:

rails s

在服务器处理任何请求之前,我可以:

• 用control-C停止它
• 用control-Z暂停它

在服务器处理完一个请求之后,我仍然可以用control-C来阻止它,但我不能再用control-Z暂停它.键入control-Z将"^ Z"回显到终端,但服务器继续运行并将处理它收到的任何请求.

为什么一旦服务器处理完请求,control-Z就无法挂起服务器？

细节

启动服务器:

$ rails s
Warning: NLS_LANG is not set. fallback to US7ASCII.
=> Booting WEBrick
=> Rails 4.1.6 application starting in development on http://0.0.0.0:3000
=> Run `rails server -h` for more startup options
=> Notice: server is listening on all interfaces (0.0.0.0). Consider using 127.0.0.1 (--binding option)
=> Ctrl-C to shutdown server
[2014-10-28 15:16:09] INFO  WEBrick 1.3.1
[2014-10-28 15:16:09] INFO  ruby 2.1.2 (2014-05-08) [i686-linux]
[2014-10-28 15:16:09] INFO  WEBrick::HTTPServer#start: pid=29538 port=3000

服务器处理任何请求之前的Control-Z:

$ rails s
Warning: NLS_LANG is not set. fallback to US7ASCII.
=> Booting WEBrick
=> Rails 4.1.6 application starting in development on http://0.0.0.0:3000
=> Run `rails server -h` for more startup options
=> Notice: server is listening on all interfaces (0.0.0.0). Consider using 127.0.0.1 (--binding option)
=> Ctrl-C to shutdown server
^Z
[1]+  Stopped                 rails s

处理请求:

Started GET "/" for 127.0.0.1 at 2014-10-28 15:18:24 -0700
  ActiveRecord::SchemaMigration Load (4.2ms)  SELECT "SCHEMA_MIGRATIONS".* FROM "SCHEMA_MIGRATIONS"
   (69.1ms)  SELECT column_name AS name, data_type AS sql_type, data_default, nullable, virtual_column, hidden_column, data_type_owner AS sql_type_owner, DECODE(data_type, 'NUMBER', data_precision, 'FLOAT', data_precision, 'VARCHAR2', DECODE(char_used, 'C', char_length, data_length), 'RAW', DECODE(char_used, 'C', char_length, data_length), 'CHAR', DECODE(char_used, 'C', char_length, data_length), NULL) AS limit, DECODE(data_type, 'NUMBER', data_scale, NULL) AS scale FROM all_tab_cols WHERE owner = 'DOCUMENT_DIRECTOR_DEVELOPMENT' AND table_name = 'SCHEMA_MIGRATIONS' AND hidden_column = 'NO' ORDER BY column_id
Processing by IndexController#index as JSON
  Rendered index/index.json.jbuilder (3.1ms)
Completed 200 OK in 10ms (Views: 9.9ms | ActiveRecord: 0.0ms)

处理请求后控制-Z,多次按下,因为我指的是业务:

^Z^Z^Z^Z^Z^Z

的Gemfile:

source 'https://rubygems.org'
source 'http://gems:9292'

gem 'activerecord-oracle_enhanced-adapter',
  git: 'https://github.com/wconrad/oracle-enhanced.git',
  branch: 'better-system-password-entry'
gem 'apipie-rails'
gem 'capistrano-rails', group: :development
gem 'capistrano-rvm'
gem 'cucumber-rails', :require => false, group: [:test]
gem 'cute_print'
gem 'database_cleaner', group: [:development, :test]
gem 'factory_girl_rails', group: [:development, :test]
gem 'jbuilder'
gem 'jsonpath', group: :test
gem 'maruku'
gem 'newrelic_rpm'
gem 'opacs_billing'
gem 'opacs_db'
gem 'rails'
gem 'rails-erd', group: :development
gem 'retryable'
gem 'rspec-rails', group: [:development, :test]
gem 'ruby-oci8'
gem 'sass-rails'
gem 'sdoc', group: :doc
gem 'simplecov', require: false, group: :test
gem 'spring', group: :development
gem 'versionist'
gem 'yard'

版本:

• MRI 2.1.2
• Rails 4.1.6
• bash 4.2.37
• Debian GNU/Linux"wheezy"

Answer 1

在您在问题评论部分写的评论之一中，您说：

用例是：control-Z，然后“bg”在后台恢复服务器，然后尾部日志。

我认为问题在于将服务器放在后台而不是前台（使用 command fg）。如果您将服务器置于后台，控制台将无法再停止它，直到您将其置于前台，因此 CTRL-Z 将不起作用。所以，我会尝试以下顺序：

1. rails s
2. CONTROL-Z（程序暂停）
3. fg（节目继续）
4. CONTROL-Z（程序是否再次停止？）

如果您想继续将服务器置于后台，那么您可以向其发送停止信号，不是通过键入 CONTROL-Z，而是通过使用以下命令发送信号kill：

kill -STOP <SERVER_PID> 

或者

kill -s STOP <SERVER_PID>

（取决于您的系统）。

要恢复该过程：

kill -CONT <SERVER_PID>

或者

kill -s CONT <SERVER_PID>