class MCollective::Facts::Base

A base class for fact providers, to make a new fully functional fact provider inherit from this and simply provide a self.get_facts method that returns a hash like:

{"foo" => "bar",
 "bar" => "baz"}

Public Class Methods

inherited(klass) click to toggle source

Registers new fact sources into the plugin manager

   # File lib/mcollective/facts/base.rb
18 def self.inherited(klass)
19   PluginManager << {:type => "facts_plugin", :class => klass.to_s}
20 end
new() click to toggle source
   # File lib/mcollective/facts/base.rb
10 def initialize
11   @mutex = Mutex.new
12   @facts = {}
13   @last_good_facts = {}
14   @last_facts_load = 0
15 end

Public Instance Methods

force_reload?() click to toggle source

Plugins can override this to provide forced fact invalidation

   # File lib/mcollective/facts/base.rb
78 def force_reload?
79   false
80 end
get_fact(fact=nil) click to toggle source

Returns the value of a single fact

   # File lib/mcollective/facts/base.rb
23 def get_fact(fact=nil)
24   config = Config.instance
25 
26   cache_time = config.fact_cache_time || 300
27 
28   @mutex.synchronize do
29     begin
30       if (Time.now.to_i - @last_facts_load > cache_time.to_i ) || force_reload?
31         Log.debug("Resetting facter cache, now: #{Time.now.to_i} last-known-good: #{@last_facts_load}")
32 
33         tfacts = load_facts_from_source
34 
35         # Force reset to last known good state on empty facts
36         raise "Got empty facts" if tfacts.empty?
37 
38         @facts = normalize_facts(tfacts)
39 
40         @last_good_facts = @facts.clone
41         @last_facts_load = Time.now.to_i
42       else
43         Log.debug("Using cached facts now: #{Time.now.to_i} last-known-good: #{@last_facts_load}")
44       end
45     rescue Exception => e
46       Log.error("Failed to load facts: #{e.class}: #{e}")
47 
48       # Avoid loops where failing fact loads cause huge CPU
49       # loops, this way it only retries once every cache_time
50       # seconds
51       @last_facts_load = Time.now.to_i
52 
53       # Revert to last known good state
54       @facts = @last_good_facts.clone
55     end
56   end
57 
58 
59   # If you do not supply a specific fact all facts will be returned
60   if fact.nil?
61     return @facts
62   else
63     @facts.include?(fact) ? @facts[fact] : nil
64   end
65 end
get_facts() click to toggle source

Returns all facts

   # File lib/mcollective/facts/base.rb
68 def get_facts
69   get_fact(nil)
70 end
has_fact?(fact) click to toggle source

Returns true if we know about a specific fact, false otherwise

   # File lib/mcollective/facts/base.rb
73 def has_fact?(fact)
74   get_fact(nil).include?(fact)
75 end