如何从Chef Cookbook中的库访问当前节点？ [英] How can I access the current node from a library in a Chef cookbook?

问题描述

我正在尝试为厨师食谱编写一个图书馆，以简化一些常见搜索。

I'm attempting to write a library for a chef cookbook that simplifies some common searches.

例如，我希望能够做类似的事情在 cookbook / libraries / library.rb 中，然后从同一食谱中的食谱中使用它：

For example, I'd like to be able to do something like this in cookbook/libraries/library.rb and then use it from a recipe in the same cookbook:

module Example
    def self.search_attribute(attribute_name)
        return search(:nodes, node[attribute_name])
    end
end

问题在于，Chef库文件中的节点对象或 search 函数可用。

The problem is that, inside a Chef library file neither the node object or search function are available.

似乎可以使用 Chef进行搜索:: Search :: Query.new（）。search（...），但找不到任何可用来访问 node 的东西。由此产生的错误是：

Search seems to be possible by using Chef::Search::Query.new().search(...), but I can't find anything that works to access node. The resulting error from this is:

undefined local variable or method `node' for Example:Module

使用Chef 10.16.4。

Using Chef 10.16.4.

推荐答案

您可以做的是将模块包含在配方中。这样，您的模块函数就可以访问配方的方法，包括 node 。

What you can do is to include the module in your recipe. That way, your module functions get access to the methods of the recipe, including node.

我通常这样做对于我的库模块：

I normally do this for my library modules:

# my_cookbook/libraries/helpers.rb
module MyCookbook
  module Helpers
    def foo
      node["foo"]
    end
  end
end

然后，在配方中，我将该模块包含在配方的当前实例中：

Then, in the recipe, I include the module into the current instance of a recipe:

# my_cookbook/recipes/default.rb
extend MyCookbook::Helpers

或者，您可以将当前节点传递为函数的参数。这样，您就不需要包含模块（保留模块名称空间的好处），而具有更复杂的方法调用的缺点。

Alternatively, you could pass the current node as a parameter to the function. That way, you don't need to include the module (which has the upside of keeping the module namespaces) but has the downside of a more convoluted method call.

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