Class: Chef::Node::Attribute

Inherits:
Mash show all
Includes:
Immutablize, Enumerable
Defined in:
lib/chef/node/attribute.rb

Overview

Attribute

Attribute implements a nested key-value (Hash) and flat collection (Array) data structure supporting multiple levels of precedence, such that a given key may have multiple values internally, but will only return the highest precedence value when reading.

Constant Summary collapse

COMPONENTS =

List of the component attribute hashes, in order of precedence, low to high.

[
  :@default,
  :@env_default,
  :@role_default,
  :@force_default,
  :@normal,
  :@override,
  :@role_override,
  :@env_override,
  :@force_override,
  :@automatic
].freeze
DEFAULT_COMPONENTS = 
[
  :@default,
  :@env_default,
  :@role_default,
  :@force_default
]
OVERRIDE_COMPONENTS = 
[
  :@override,
  :@role_override,
  :@env_override,
  :@force_override
]

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Immutablize

#immutablize

Methods inherited from Mash

#delete, #except, #fetch, from_hash, #initialize_copy, #merge, #regular_update, #regular_writer, #stringify_keys!, #symbolize_keys, #to_hash, #update, #values_at

Constructor Details

#initialize(normal, default, override, automatic) ⇒ Attribute

Returns a new instance of Attribute.



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# File 'lib/chef/node/attribute.rb', line 190

def initialize(normal, default, override, automatic)
  @set_unless_present = false

  @default = VividMash.new(self, default)
  @env_default = VividMash.new(self, {})
  @role_default = VividMash.new(self, {})
  @force_default = VividMash.new(self, {})

  @normal = VividMash.new(self, normal)

  @override = VividMash.new(self, override)
  @role_override = VividMash.new(self, {})
  @env_override = VividMash.new(self, {})
  @force_override = VividMash.new(self, {})

  @automatic = VividMash.new(self, automatic)

  @merged_attributes = nil
  @combined_override = nil
  @combined_default = nil
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(symbol, *args) ⇒ Object 



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# File 'lib/chef/node/attribute.rb', line 353

def method_missing(symbol, *args)
  if args.empty?
    if key?(symbol)
      self[symbol]
    else
      raise NoMethodError, "Undefined method or attribute `#{symbol}' on `node'"
    end
  elsif symbol.to_s =~ /=$/
    key_to_set = symbol.to_s[/^(.+)=$/, 1]
    self[key_to_set] = (args.length == 1 ? args[0] : args)
  else
    raise NoMethodError, "Undefined node attribute or method `#{symbol}' on `node'"
  end
end

Instance Attribute Details

#automatic ⇒ Object

return the automatic level attribute component



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# File 'lib/chef/node/attribute.rb', line 188

def automatic
  @automatic
end

#default ⇒ Object

return the cookbook level default attribute component



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# File 'lib/chef/node/attribute.rb', line 151

def default
  @default
end

#env_default ⇒ Object

return the environment level default attribute component



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# File 'lib/chef/node/attribute.rb', line 157

def env_default
  @env_default
end

#env_override ⇒ Object

return the enviroment level override attribute component



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# File 'lib/chef/node/attribute.rb', line 177

def env_override
  @env_override
end

#force_default ⇒ Object Also known as: default!

return the force_default level attribute component



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# File 'lib/chef/node/attribute.rb', line 160

def force_default
  @force_default
end

#force_override ⇒ Object Also known as: override!

return the force override level attribute component



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# File 'lib/chef/node/attribute.rb', line 180

def force_override
  @force_override
end

#normal ⇒ Object

return the “normal” level attribute component



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# File 'lib/chef/node/attribute.rb', line 168

def normal
  @normal
end

#override ⇒ Object

return the cookbook level override attribute component



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# File 'lib/chef/node/attribute.rb', line 171

def override
  @override
end

#role_default ⇒ Object

return the role level default attribute component



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# File 'lib/chef/node/attribute.rb', line 154

def role_default
  @role_default
end

#role_override ⇒ Object

return the role level override attribute component



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# File 'lib/chef/node/attribute.rb', line 174

def role_override
  @role_override
end

Instance Method Details

#[](key) ⇒ Object 



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# File 'lib/chef/node/attribute.rb', line 332

def [](key)
  merged_attributes[key]
end

#[]=(key, value) ⇒ Object 



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# File 'lib/chef/node/attribute.rb', line 336

def []=(key, value)
  merged_attributes[key] = value
end

#combined_default ⇒ Object 



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# File 'lib/chef/node/attribute.rb', line 328

def combined_default
  @combined_default ||= immutablize(merge_defaults)
end

#combined_override ⇒ Object 



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# File 'lib/chef/node/attribute.rb', line 324

def combined_override
  @combined_override ||= immutablize(merge_overrides)
end

#debug_value(*args) ⇒ Object

Debug what’s going on with an attribute. args is a path spec to the attribute you’re interested in. For example, to debug where the value of ‘node[:default_interface]` is coming from, use:

debug_value(:network, :default_interface).

The return value is an Array of Arrays. The first element is ‘[“set_unless_enabled?”, Boolean]`, which describes whether the attribute collection is in “set_unless” mode. The rest of the Arrays are pairs of `[“precedence_level”, value]`, where precedence level is the component, such as role default, normal, etc. and value is the attribute value set at that precedence level. If there is no value at that precedence level, value will be the symbol :not_present.



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# File 'lib/chef/node/attribute.rb', line 223

def debug_value(*args)
  components = COMPONENTS.map do |component|
    ivar = instance_variable_get(component)
    value = args.inject(ivar) do |so_far, key|
      if so_far == :not_present
        :not_present
      elsif so_far.has_key?(key)
        so_far[key]
      else
        :not_present
      end
    end
    [component.to_s.sub(/^@/,""), value]
  end
  [["set_unless_enabled?", @set_unless_present]] + components
end

#has_key?(key) ⇒ Boolean Also known as: attribute?, member?, include?, key?

Returns:

  • (Boolean) 


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# File 'lib/chef/node/attribute.rb', line 340

def has_key?(key)
  COMPONENTS.any? do |component_ivar|
    instance_variable_get(component_ivar).has_key?(key)
  end
end

#inspect ⇒ Object 



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# File 'lib/chef/node/attribute.rb', line 368

def inspect
  "#<#{self.class} " << (COMPONENTS + [:@merged_attributes, :@properties]).map{|iv|
    "#{iv}=#{instance_variable_get(iv).inspect}"
  }.join(', ') << ">"
end

#merged_attributes ⇒ Object 



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# File 'lib/chef/node/attribute.rb', line 314

def merged_attributes
  @merged_attributes ||= begin
                           components = [merge_defaults, @normal, merge_overrides, @automatic]
                           resolved_attrs = components.inject(Mash.new) do |merged, component|
                             Chef::Mixin::DeepMerge.hash_only_merge(merged, component)
                           end
                           immutablize(resolved_attrs)
                         end
end

#reset_cache ⇒ Object Also known as: reset

Clears merged_attributes, which will cause it to be recomputed on the next access.



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# File 'lib/chef/node/attribute.rb', line 247

def reset_cache
  @merged_attributes = nil
  @combined_default  = nil
  @combined_override = nil
  @set_unless_present = false
end

#set_unless? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/chef/node/attribute.rb', line 374

def set_unless?
  @set_unless_present
end

#set_unless_value_present=(setting) ⇒ Object

Enables or disables ‘||=`-like attribute setting. See, e.g., Node#set_unless



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# File 'lib/chef/node/attribute.rb', line 241

def set_unless_value_present=(setting)
  @set_unless_present = setting
end