ruby-on-rails - Chef 模板变量@node 似乎抛出错误

Question

我正在阅读 peepcode 的 Chef 教程，到目前为止还不错。由于某种原因，使用模板变量时会失败。该示例适用于 nginx。

在 nginx/attributes/nginx.rb 我有:

default[:nginx][:worker_processes] = 4

在 nginx.conf.erb 模板中我指的是:

worker_processes  <%= @node[:nginx][:worker_processes] %>;

以下是我在运行 Chef-solo 时遇到的错误:

Template Context:
-----------------
on line #2
  1: user www-data;
  2: worker_processes  <%= @node[:nginx][:worker_processes] %>;
  3: 
  4: error_log  /var/log/nginx/error.log;
  5: pid        /var/run/nginx.pid;


[2013-07-14T19:46:36+02:00] ERROR: Running exception handlers
[2013-07-14T19:46:36+02:00] ERROR: Exception handlers complete
Chef Client failed. 0 resources updated
[2013-07-14T19:46:36+02:00] FATAL: Stacktrace dumped to /var/chef/cache/chef-stacktrace.out
[2013-07-14T19:46:36+02:00] FATAL: Chef::Mixin::Template::TemplateError: undefined method `[]' for nil:NilClass

错误输出的其他部分:

Starting Chef Client, version 11.4.4
Compiling Cookbooks...
Converging 3 resources
Recipe: nginx::default
  * package[nginx] action install (up to date)
  * service[nginx] action enable (up to date)
  * service[nginx] action start (up to date)
  * template[/etc/nginx/nginx.conf] action create
================================================================================
Error executing action `create` on resource 'template[/etc/nginx/nginx.conf]'
================================================================================


Chef::Mixin::Template::TemplateError
------------------------------------
undefined method `[]' for nil:NilClass


Resource Declaration:
---------------------
# In /cookbooks/nginx/recipes/default.rb

  8: template "/etc/nginx/nginx.conf" do
  9:    notifies :reload, "service[nginx]"
 10: end



Compiled Resource:
------------------
# Declared in /cookbooks/nginx/recipes/default.rb:8:in `from_file'

template("/etc/nginx/nginx.conf") do
  provider Chef::Provider::Template
  action "create"
  retries 0
  retry_delay 2
  path "/etc/nginx/nginx.conf"
  backup 5
  source "nginx.conf.erb"
  cookbook_name :nginx
  recipe_name "default"
end

Answer 1

您可以访问模板中的对象变量(以@ 开头的变量)，前提是您通过 variables 传递它们。这样的模板方法:

template("/etc/nginx/nginx.conf") do
  [...]
  variables( :my_var => node )
  [...]
end

那么您将拥有 @my_var在模板中可用。但您不必通过 node ，因为它已经在模板中可用。您只需要访问它而不是作为对象变量。模板中的以下代码应该可以工作。

<%= node[:nginx][:worker_processes] %>

只需删除 @从前面 node .