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