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

Instance Method Summary collapse

Methods included from Core::Execution

absolute_path?, exec, 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, #value

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.



56
57
58
59
60
61
62
63
 
# 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

#code ⇒ Object

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. 



21
22
23
 
# File 'lib/facter/util/resolution.rb', line 21

def code
  @code
end

#fact ⇒ Facter::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:



48
49
50
 
# File 'lib/facter/util/resolution.rb', line 48

def fact
  @fact
end

#name ⇒ String

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

Returns:

  • (String) 


43
44
45
 
# File 'lib/facter/util/resolution.rb', line 43

def name
  @name
end

#value=(value) ⇒ Object (writeonly) 



22
23
24
 
# File 'lib/facter/util/resolution.rb', line 22

def value=(value)
  @value = value
end

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.



69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
 
# File 'lib/facter/util/resolution.rb', line 69

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

#set_options(options) ⇒ Object 



89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
 
# File 'lib/facter/util/resolution.rb', line 89

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.



128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
 
# File 'lib/facter/util/resolution.rb', line 128

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