add inventory caching & use in virtualbox inventory plugin (#34510)

* Inventory caching

* Add inventory caching for virtualbox

* Don't populate cache for virtualbox with stdout, use a dict of inventory instead

* Fix error creating the cache dir if it doesn't exist

* Keep cache default False and set to True in VariableManager __init__

* Check all groups before determining if a host is ungrouped.

lib/ansible/plugins/cache/__init__.py

@@ -79,12 +79,24 @@ class BaseFileCacheModule(BaseCacheModule):
         self.plugin_name = self.__module__.split('.')[-1]
         self._timeout = float(C.CACHE_PLUGIN_TIMEOUT)
         self._cache = {}
-        self._cache_dir = None
+        self._cache_dir = self._get_cache_connection(C.CACHE_PLUGIN_CONNECTION)
+        self._set_inventory_cache_override(**kwargs)
+        self.validate_cache_connection()
 
-        if C.CACHE_PLUGIN_CONNECTION:
-            # expects a dir path
-            self._cache_dir = os.path.expanduser(os.path.expandvars(C.CACHE_PLUGIN_CONNECTION))
+    def _get_cache_connection(self, source):
+        if source:
+            try:
+                return os.path.expanduser(os.path.expandvars(source))
+            except TypeError:
+                pass
 
+    def _set_inventory_cache_override(self, **kwargs):
+        if kwargs.get('cache_timeout'):
+            self._timeout = kwargs.get('cache_timeout')
+        if kwargs.get('cache_connection'):
+            self._cache_dir = self._get_cache_connection(kwargs.get('cache_connection'))
+
+    def validate_cache_connection(self):
         if not self._cache_dir:
             raise AnsibleError("error, '%s' cache plugin requires the 'fact_caching_connection' config option "
                                "to be set (to a writeable directory path)" % self.plugin_name)
@@ -141,7 +153,7 @@ class BaseFileCacheModule(BaseCacheModule):
     def has_expired(self, key):
 
         if self._timeout == 0:
-            return False
+            return True
 
         cachefile = "%s/%s" % (self._cache_dir, key)
         try:
@@ -284,3 +296,52 @@ class FactCache(MutableMapping):
         host_cache = self._plugin.get(key)
         host_cache.update(value)
         self._plugin.set(key, host_cache)
+
+
+class InventoryFileCacheModule(BaseFileCacheModule):
+    """
+    A caching module backed by file based storage.
+    """
+    def __init__(self, plugin_name, timeout, cache_dir):
+
+        self.plugin_name = plugin_name
+        self._timeout = timeout
+        self._cache = {}
+        self._cache_dir = self._get_cache_connection(cache_dir)
+        self.validate_cache_connection()
+        self._plugin = self.get_plugin(plugin_name)
+
+    def validate_cache_connection(self):
+        try:
+            super(InventoryFileCacheModule, self).validate_cache_connection()
+        except AnsibleError as e:
+            cache_connection_set = False
+        else:
+            cache_connection_set = True
+
+        if not cache_connection_set:
+            raise AnsibleError("error, '%s' inventory cache plugin requires the one of the following to be set:\n"
+                               "ansible.cfg:\n[default]: fact_caching_connection,\n[inventory]: cache_connection;\n"
+                               "Environment:\nANSIBLE_INVENTORY_CACHE_CONNECTION,\nANSIBLE_CACHE_PLUGIN_CONNECTION."
+                               "to be set to a writeable directory path" % self.plugin_name)
+
+    def get(self, cache_key):
+
+        if not self.contains(cache_key):
+            # Check if cache file exists
+            raise KeyError
+
+        return super(InventoryFileCacheModule, self).get(cache_key)
+
+    def get_plugin(self, plugin_name):
+        plugin = cache_loader.get(plugin_name, cache_connection=self._cache_dir, cache_timeout=self._timeout)
+        if not plugin:
+            raise AnsibleError('Unable to load the facts cache plugin (%s).' % (plugin_name))
+        self._cache = {}
+        return plugin
+
+    def _load(self, path):
+        return self._plugin._load(path)
+
+    def _dump(self, value, path):
+        return self._plugin._dump(value, path)