Class: MCollective::Facts::Base

Inherits:
Object
  • Object
show all
Defined in:
lib/mcollective/facts/base.rb

Overview

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"}

Direct Known Subclasses

Yaml_facts

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Base

Returns a new instance of Base.



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# File 'lib/mcollective/facts/base.rb', line 10

def initialize
  @mutex = Mutex.new
  @facts = {}
  @last_good_facts = {}
  @last_facts_load = 0
end

Class Method Details

.inherited(klass) ⇒ Object

Registers new fact sources into the plugin manager



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# File 'lib/mcollective/facts/base.rb', line 18

def self.inherited(klass)
  PluginManager << {:type => "facts_plugin", :class => klass.to_s}
end

Instance Method Details

#force_reload? ⇒ Boolean

Plugins can override this to provide forced fact invalidation

Returns:

  • (Boolean) 


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# File 'lib/mcollective/facts/base.rb', line 78

def force_reload?
  false
end

#get_fact(fact = nil) ⇒ Object

Returns the value of a single fact



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# File 'lib/mcollective/facts/base.rb', line 23

def get_fact(fact=nil)
  config = Config.instance

  cache_time = config.fact_cache_time || 300

  @mutex.synchronize 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 = normalize_facts(tfacts)

        @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 ⇒ Object

Returns all facts



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# File 'lib/mcollective/facts/base.rb', line 68

def get_facts
  get_fact(nil)
end

#has_fact?(fact) ⇒ Boolean

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

Returns:

  • (Boolean) 


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# File 'lib/mcollective/facts/base.rb', line 73

def has_fact?(fact)
  get_fact(nil).include?(fact)
end