Ruby on rails 不正确的deploy.rb-“部署错误”；命名错误：未定义的方法“tail'；对于nil:NilClass“；

下面是我的部署.rb的外观

set :application, 'myapp'

set :scm, :git

set :repo_url, 'git@bitbucket.org:me/myapp.git'
set :pty, true
set :deploy_to, "/home/deployer/apps/myapp-staging"

namespace :deploy do
  %w[start stop restart].each do |command|
    desc "#{command} unicorn server"
    task command, roles: :app, except: {no_release: true} do
      #run "/etc/init.d/unicorn_#{application} #{command}"
      run "/etc/init.d/unicorn_myapp-staging #{command}"
    end
  end

  task :setup_config, roles: :app do
    sudo "ln -nfs #{current_path}/config/nginx.conf /etc/nginx/sites-enabled/myapp"
    sudo "ln -nfs #{current_path}/config/unicorn_init.sh /etc/init.d/unicorn_myapp-staging"
    run "mkdir -p #{shared_path}/config"
    put File.read("config/database.example.yml"), "#{shared_path}/config/database.yml"
    puts "Now edit the config files in #{shared_path}."
  end
  after "deploy:setup", "deploy:setup_config"

  task :symlink_config, roles: :app do
    run "ln -nfs #{shared_path}/config/database.yml #{release_path}/config/database.yml"
  end
  after "deploy:finalize_update", "deploy:symlink_config"

  desc "Make sure local git is in sync with remote."
  task :check_revision, roles: :web do
    unless `git rev-parse HEAD` == `git rev-parse origin/master`
      puts "WARNING: HEAD is not the same as origin/master"
      puts "Run `git push` to sync changes."
      exit
    end
  end
  before "deploy", "deploy:check_revision"
end

部署代码时，会出现以下错误：

** Invoke staging (first_time)
** Execute staging
** Invoke load:defaults (first_time)
** Execute load:defaults
cap aborted!
NoMethodError: undefined method `tail' for nil:NilClass
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/task_manager.rb:212:in `ensure in in_namespace'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/task_manager.rb:212:in `in_namespace'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/dsl_definition.rb:146:in `namespace'
config/deploy.rb:75:in `<top (required)>'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/capistrano-3.2.1/lib/capistrano/setup.rb:14:in `load'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/capistrano-3.2.1/lib/capistrano/setup.rb:14:in `block (2 levels) in <top (required)>'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/task.rb:240:in `call'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/task.rb:240:in `block in execute'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/task.rb:235:in `each'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/task.rb:235:in `execute'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/task.rb:179:in `block in invoke_with_call_chain'
/Users/adam/.rvm/rubies/ruby-1.9.3-p385/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/task.rb:172:in `invoke_with_call_chain'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/task.rb:165:in `invoke'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/application.rb:150:in `invoke_task'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/application.rb:106:in `block (2 levels) in top_level'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/application.rb:106:in `each'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/application.rb:106:in `block in top_level'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/application.rb:115:in `run_with_threads'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/application.rb:100:in `top_level'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/application.rb:78:in `block in run'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/application.rb:176:in `standard_exception_handling'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/application.rb:75:in `run'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/capistrano-3.2.1/lib/capistrano/application.rb:15:in `run'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/capistrano-3.2.1/bin/cap:3:in `<top (required)>'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/bin/cap:19:in `load'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/bin/cap:19:in `<main>'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/bin/ruby_noexec_wrapper:14:in `eval'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/bin/ruby_noexec_wrapper:14:in `<main>'
Tasks: TOP => staging

**调用暂存（第一次）
**执行分段
**调用加载：默认值（第一次）
**执行加载：默认值
帽子流产了！
NoMethodError:nil:NilClass的未定义方法“tail”
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/task_manager.rb:212:“确保在名称空间中”
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/task_manager.rb:212:in`in_名称空间'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/dsl_definition.rb:146:在“名称空间”中
config/deploy.rb:75:in`'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/capistrano-3.2.1/lib/capistrano/setup.rb:14:in'load'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/capistrano-3.2.1/lib/capistrano/setup.rb:14:in“block（2层）in”
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/task.rb:240:in'call'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/task.rb:240:in'block in execute'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/task.rb:235:in'each'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/task.rb:235:in'execute'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/task.rb:179:in`block in invoke_with_call_chain'
/Users/adam/.rvm/rubies/ruby-1.9.3-p385/lib/ruby/1.9.1/monitor.rb:211:in'mon_synchronize'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/task.rb:172:在'invoke_with_call_chain'中
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/task.rb:165:in'invoke'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/application.rb:150:在“调用任务”中
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/application.rb:106:在“顶层的块（2层）”中
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/application.rb:106:in'each'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/application.rb:106:在“顶层块”中
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/application.rb:115:在“使用线程运行”中
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/application.rb:100:“顶级”
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/application.rb:78:in'block in run'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/application.rb:176:在“标准异常处理”中
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/rake-10.3.2/lib/rake/application.rb:75:in'run'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/capistrano-3.2.1/lib/capistrano/application.rb:15:在“运行”中
/Users/adam/.rvm/gems/ruby-1.9.3-p385/gems/capistrano-3.2.1/bin/cap:3:in`'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/bin/cap:19:in'load'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/bin/cap:19:in`'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/bin/ruby\u noexec\u包装：14:in'eval'
/Users/adam/.rvm/gems/ruby-1.9.3-p385/bin/ruby\u noexec\u包装：14:in`'
任务：TOP=>staging

如果删除名称空间块，错误就消失了，但我需要它。这个错误是什么原因造成的？我整个下午都在和它斗争，但仍然不知道如何摆脱它

---

提前感谢各位。

这是因为您正在使用Capistrano v2 DSL和Capistrano v3，这是不兼容的

您需要将选项

roles:：app

替换为一个块，例如：

task :my_task do    
  on roles(:app) do
    ...
  end
end

---

请参阅中的“更具表现力的命令语言”。

这是因为您使用的是Capistrano v2 DSL和Capistrano v3，这是不兼容的

您需要将选项

roles:：app

替换为一个块，例如：

task :my_task do    
  on roles(:app) do
    ...
  end
end

---

请参阅中的“更具表现力的命令语言”。

您是否使用capistrano的3.0.1/3.1.0版？本期在Capistrano 3.0.1/3.1.0上发布。事实上，我不知道如何解决这个问题，但有些人通过降级到Capistrano 2来解决这个问题。尽管如此，我还是尝试了Capistrano从3.0.1升级到最新版本。不能让我降级到2.x其他一些问题？你能解决这个问题吗？我也面临着完全相同的问题，您是否使用capistrano的3.0.1/3.1.0版？本期在Capistrano 3.0.1/3.1.0上发布。事实上，我不知道如何解决这个问题，但有些人通过降级到Capistrano 2来解决这个问题。尽管如此，我还是尝试了Capistrano从3.0.1升级到最新版本。不能让我降级到2.x其他一些问题？你能解决这个问题吗？我也面临着同样的问题