LWRP 领导者 "undefined method 'checkname' for nil:NilClass"

Question

我正在尝试为 Chef 食谱编写 LWRP，但我运行遇到了一个奇怪的问题，其中属性似乎在一行中完全有效，并且 nil下一个。

来自提供商代码，source 行错误：

def create_check
  cookbook_file get_check_filename(@current_resource.checkname) do
    source  "checks/#{@current_resource.checkname}" # undefined method `checkname' for nil:NilClass
    mode    '0644'
    action  :create
  end
end

和 load_current_resource 方法只是为了表明它是初始化的：

def load_current_resource
  @current_resource = Chef::Resource::OmdCheck.new(@new_resource_name)
  @current_resource.checkname(@new_resource.checkname) # right here!
  @current_resource.sitename(@new_resource.sitename)
  @current_resource.sitecfgroot(sprintf(CMK_CFGROOT_FRM, @new_resource.sitename))
  @current_resource.perfometer(@new_resource.perfometer)
  @current_resource.pnptemplate(@new_resource.pnptemplate)

  @current_resource.exists = check_exists?(@current_resource.checkname)
end

非常感谢任何帮助。

Answer 1

所以我在#chef 上得到了答案：

<@coderanger> Sammitch: Use current_resource, not @current_resource
< Sammitch> it's passed in as an instance var?
<@coderanger> Sammitch: No, its actually a method on Provider
<@coderanger> as is new_resource
<@coderanger> the issue is that the block on a resource is evaluated against the resource object
<@coderanger> So in there, @foo is looking at an ivar on the new resource object
<@coderanger> _but_ there is some magic
<@coderanger> Chef::Resource has a method_missing to forward unknown method calls to the enclosing provider
<@coderanger> So #current_resource gets forwarded up for you
<@coderanger> Basically never use the ivar form
<@coderanger> Always new_resource and current_resource instead
<@coderanger> and it will mostly JFW

就 Ruby 和 Chef 而言，我还很新手，所以只有 20% 对我有意义，但我修改了我的代码到下面并且有效：

def create_check
  cookbook_file get_check_filename(@current_resource.checkname) do
    source  "checks/#{current_resource.checkname}" # removed the @
    mode    '0644'
    action  :create
  end
end

Answer 2

您通常必须将方法放在 () 中的“#{}”中
示例：

"#{method}"        # does not work
"#{(method)}"      # works
a = method; "#{a}" # works too

LWRP 领导者 "undefined method 'checkname' for nil:NilClass"

Chef LWRP "undefined method 'checkname' for nil:NilClass"

ruby

chef-infra

lwrp