6057 - Yaml fact plugin should check mtime of files

Create a new hook for fact plugins to override fact cache
aging.  A fact plugin can define force_reload? which should
return true or false.

lib/mcollective/facts/base.rb

@@ -26,8 +26,8 @@ def get_fact(fact=nil)
 
                 Thread.exclusive do
                     begin
-                        if (Time.now.to_i - @last_facts_load > cache_time.to_i )
-                            Log.debug("Resetting facter cache after #{cache_time} seconds, now: #{Time.now.to_i} last-known-good: #{@last_facts_load}")
+                        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
 
@@ -76,6 +76,11 @@ def get_facts
             def has_fact?(fact)
                 get_fact(nil).include?(fact)
             end
+
+            # Plugins can override this to provide forced fact invalidation
+            def force_reload?
+                false
+            end
         end
     end
 end

plugins/mcollective/facts/yaml_facts.rb

@@ -8,6 +8,12 @@ module Facts
         # config file, they will be merged with later files overriding
         # earlier ones in the list.
         class Yaml_facts<Base
+            def initialize
+                @yaml_file_mtimes = {}
+
+                super
+            end
+
             def load_facts_from_source
                 config = Config.instance
 
@@ -28,6 +34,28 @@ def load_facts_from_source
 
                 facts
             end
+
+            # force fact reloads when the mtime on the yaml file change
+            def force_reload?
+                config = Config.instance
+
+                fact_files = config.pluginconf["yaml"].split(":")
+
+                fact_files.each do |file|
+                    @yaml_file_mtimes[file] ||= File.stat(file).mtime
+                    mtime = File.stat(file).mtime
+
+                    if mtime > @yaml_file_mtimes[file]
+                        @yaml_file_mtimes[file] = mtme
+
+                        Log.debug("Forcing fact reload due to age of #{file}")
+
+                        return true
+                    end
+                end
+
+                false
+            end
         end
     end
 end

website/changelog.md

@@ -11,6 +11,8 @@ title: Changelog
 
 |Date|Description|Ticket|
 |----|-----------|------|
+|2011/01/30|Let the YAML file force fact reloads when the files update|6057|
+|2011/01/30|Add the ability for fact plugins to force fact invalidation|6057|
 |2011/01/30|Document an approach to disable type validation in the DDL|6066|
 |2011/01/19|Add basic filters to the mc-ping command|5933|
 |2011/01/19|Add a ping action to the rpcutil agent|5937|

website/reference/plugins/facts.md

@@ -67,7 +67,9 @@ end
 {% endhighlight %}
 
 If using the newer format in newer releases of mcollective you do not need to worry about caching or
-thread safety as the base class does this for you.
+thread safety as the base class does this for you.  You can force reloading of facts by creating a
+*force_reload?* method that should return *true* or *false*.  Returning *true* will force the cache
+to be rebuilt.
 
 You can see that all you have to do is provide *self.get_facts* which should return a Hash as described above.