adding caching to script plugin

lib/ansible/plugins/inventory/script.py

@@ -82,7 +82,12 @@ class InventoryModule(BaseInventoryPlugin):
         # directory when '.' is not in PATH.
         path = os.path.abspath(path)
         cmd = [ path, "--list" ]
+
         try:
+            cache_key = self.get_cache_prefix(path)
+            if cache and cache_key in inventory.cache:
+                data = inventory.cache[cache_key]
+            else:
                 try:
                     sp = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
                 except OSError as e:
@@ -103,6 +108,9 @@ class InventoryModule(BaseInventoryPlugin):
                 except Exception as e:
                     raise AnsibleError("Inventory {0} contained characters that cannot be interpreted as UTF-8: {1}".format(path, to_native(e)))
 
+                if cache:
+                    inventory.cache[cache_key] = data
+
             try:
                 processed = self.loader.load(data)
             except Exception as e: