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, line 17
def self.inherited(klass)
  PluginManager << {:type => "facts_plugin", :class => klass.to_s}
end
new() click to toggle source
# File lib/mcollective/facts/base.rb, line 10
def initialize
  @facts = {}
  @last_good_facts = {}
  @last_facts_load = 0
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, line 81
def force_reload?
  false
end
get_fact(fact=nil) click to toggle source

Returns the value of a single fact

# File lib/mcollective/facts/base.rb, line 22
def get_fact(fact=nil)
  config = Config.instance

  cache_time = config.fact_cache_time || 300

  Thread.exclusive do
    begin
      if (Time.now.to_i - @last_facts_load > cache_time.to_i ) || force_reload?
        Log.debug("Resetting facter cache, now: #{Time.now.to_i} last-known-good: #{@last_facts_load}")

        tfacts = load_facts_from_source

        # Force reset to last known good state on empty facts
        raise "Got empty facts" if tfacts.empty?

        @facts.clear

        tfacts.each_pair do |key,value|
          @facts[key.to_s] = value.to_s
        end

        @last_good_facts = @facts.clone
        @last_facts_load = Time.now.to_i
      else
        Log.debug("Using cached facts now: #{Time.now.to_i} last-known-good: #{@last_facts_load}")
      end
    rescue Exception => e
      Log.error("Failed to load facts: #{e.class}: #{e}")

      # Avoid loops where failing fact loads cause huge CPU
      # loops, this way it only retries once every cache_time
      # seconds
      @last_facts_load = Time.now.to_i

      # Revert to last known good state
      @facts = @last_good_facts.clone
    end
  end


  # If you do not supply a specific fact all facts will be returned
  if fact.nil?
    return @facts
  else
    @facts.include?(fact) ? @facts[fact] : nil
  end
end
get_facts() click to toggle source

Returns all facts

# File lib/mcollective/facts/base.rb, line 71
def get_facts
  get_fact(nil)
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, line 76
def has_fact?(fact)
  get_fact(nil).include?(fact)
end