Class: Facter::Util::Resolution

Inherits:
Object
  • Object
show all
Extended by:
Core::Execution
Includes:
Core::Resolvable, Core::Suitable
Defined in:
lib/facter/util/resolution.rb

Overview

This represents a fact resolution. A resolution is a concrete implementation of a fact. A single fact can have many resolutions and the correct resolution will be chosen at runtime. Each time Facter.add is called, a new resolution is created and added to the set of resolutions for the fact named in the call. Each resolution has a weight, which defines its priority over other resolutions, and a set of _confinements, which defines the conditions under which it will be chosen. All confinements must be satisfied for a fact to be considered suitable.

Instance Attribute Summary collapse

Attributes included from Core::Suitable

#weight

Attributes included from Core::Resolvable

#timeout

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Core::Execution

absolute_path?, exec, execute, execute, expand_command, impl, search_paths, which, with_env

Methods included from Core::Suitable

#confine, #has_weight, #suitable?

Methods included from Core::Resolvable

#flush, #limit, #on_flush, #qualified_name, #value, #with_timing

Constructor Details

#initialize(name, fact) ⇒ void

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Create a new resolution mechanism.

Parameters:

  • name (String)

    The name of the resolution.



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# File 'lib/facter/util/resolution.rb', line 56

def initialize(name, fact)
  @name = name
  @fact = fact
  @confines = []
  @value = nil
  @timeout = 0
  @weight = nil
end

Instance Attribute Details

#codeObject

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.



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# File 'lib/facter/util/resolution.rb', line 21

def code
  @code
end

#factFacter::Util::Fact (readonly)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns:



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# File 'lib/facter/util/resolution.rb', line 48

def fact
  @fact
end

#nameString

The name of this resolution. The resolution name should be unique with respect to the given fact.

Returns:

  • (String)


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# File 'lib/facter/util/resolution.rb', line 43

def name
  @name
end

#value=(value) ⇒ Object (writeonly)

Sets the attribute value

Parameters:

  • value

    the value to set the attribute value to.



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# File 'lib/facter/util/resolution.rb', line 22

def value=(value)
  @value = value
end

Class Method Details

.absolute_path?Object

.execObject

.expand_commandObject

.search_pathsObject

.whichObject

.with_envObject

Instance Method Details

#evaluate(&block) ⇒ void

This method returns an undefined value.

Evaluate the given block in the context of this resolution. If a block has already been evaluated emit a warning to that effect.



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# File 'lib/facter/util/resolution.rb', line 73

def evaluate(&block)
  if @last_evaluated
    msg = "Already evaluated #{@name}"
    msg << " at #{@last_evaluated}" if msg.is_a? String
    msg << ", reevaluating anyways"
    Facter.warn msg
  end

  instance_eval(&block)

  # Ruby 1.9+ provides the source location of procs which can provide useful
  # debugging information if a resolution is being evaluated twice. Since 1.8
  # doesn't support this we opportunistically provide this information.
  if block.respond_to? :source_location
    @last_evaluated = block.source_location.join(':')
  else
    @last_evaluated = true
  end
end

#resolution_typeObject



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# File 'lib/facter/util/resolution.rb', line 65

def resolution_type
  :simple
end

#resolve_valueObject (private)



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# File 'lib/facter/util/resolution.rb', line 151

def resolve_value
  if @value
    @value
  elsif @code.nil?
    nil
  elsif @code
    @code.call()
  end
end

#set_options(options) ⇒ Object



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# File 'lib/facter/util/resolution.rb', line 93

def set_options(options)
  if options[:name]
    @name = options.delete(:name)
  end

  if options.has_key?(:value)
    @value = options.delete(:value)
  end

  if options.has_key?(:timeout)
    @timeout = options.delete(:timeout)
  end

  if options.has_key?(:weight)
    @weight = options.delete(:weight)
  end

  if not options.keys.empty?
    raise ArgumentError, "Invalid resolution options #{options.keys.inspect}"
  end
end

#setcode(string) ⇒ void #setcode(&block) ⇒ void

This method returns an undefined value.

Sets the code block or external program that will be evaluated to get the value of the fact.

Overloads:

  • #setcode(string) ⇒ void

    Sets an external program to call to get the value of the resolution

    Parameters:

    • string (String)

      the external program to run to get the value

  • #setcode(&block) ⇒ void

    Sets the resolution's value by evaluating a block at runtime

    Parameters:

    • block (Proc)

      The block to determine the resolution's value. This block is run when the fact is evaluated. Errors raised from inside the block are rescued and printed to stderr.



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# File 'lib/facter/util/resolution.rb', line 132

def setcode(string = nil, &block)
  if string
    @code = Proc.new do
      output = Facter::Core::Execution.execute(string, :on_fail => nil)
      if output.nil? or output.empty?
        nil
      else
        output
      end
    end
  elsif block_given?
    @code = block
  else
    raise ArgumentError, "You must pass either code or a block"
  end
end