class MCollective::Facts::Base - mcollective version 2.12.5

# 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