Make plugin loader path operations more efficient.

bin/ansible-doc

@@ -170,13 +170,23 @@ def main():
 
     if len(args) == 0:
         p.print_help()
-    
+   
+    def print_paths(finder):
+        ''' Returns a string suitable for printing of the search path '''
+
+        # Uses a list to get the order right
+        ret = []
+        for i in finder._get_paths():
+            if i not in ret:
+                ret.append(i)
+        return os.pathsep.join(ret)
+ 
     for module in args:
 
         filename = utils.plugins.module_finder.find_plugin(module)
         if filename is None:
             sys.stderr.write("module %s not found in %s\n" % (module,
-                    utils.plugins.module_finder.print_paths()))
+                    print_paths(utils.plugins.module_finder)))
             continue
 
         if any(filename.endswith(x) for x in BLACKLIST_EXTS):

lib/ansible/utils/plugins.py

@@ -23,34 +23,47 @@ import ansible.constants as C
 from ansible import errors
 
 MODULE_CACHE = {}
+PATH_CACHE = {}
+PLUGIN_PATH_CACHE = {}
 _basedirs = []
 
 def push_basedir(basedir):
     _basedirs.insert(0, basedir)
 
 class PluginLoader(object):
-    """PluginLoader loads plugins from the best source
+
+    '''
+    PluginLoader loads plugins from the configured plugin directories.
 
     It searches for plugins by iterating through the combined list of
-    play basedirs, configured paths, and the installed package directory.
+    play basedirs, configured paths, and the python path.
     The first match is used.
-    """
+    '''
+
     def __init__(self, class_name, package, config, subdir, aliases={}):
-        """Create a new PluginLoader"""
-        self.class_name = class_name
-        self.package = package
-        self.config = config
-        self.subdir = subdir
-        self.aliases = aliases
- 
+
+        self.class_name         = class_name
+        self.package            = package
+        self.config             = config
+        self.subdir             = subdir
+        self.aliases            = aliases
+
         if not class_name in MODULE_CACHE:
             MODULE_CACHE[class_name] = {}
+        if not class_name in PATH_CACHE:
+            PATH_CACHE[class_name] = None
+        if not class_name in PLUGIN_PATH_CACHE:
+            PLUGIN_PATH_CACHE[class_name] = {}
+
+        self._module_cache      = MODULE_CACHE[class_name]
+        self._paths             = PATH_CACHE[class_name]
+        self._plugin_path_cache = PLUGIN_PATH_CACHE[class_name]
 
-        self._module_cache = MODULE_CACHE[class_name]
         self._extra_dirs = []
 
     def _get_package_path(self):
-        """Gets the path of a Python package"""
+        ''' Gets the path of a Python package '''
+
         if not self.package:
             return []
         if not hasattr(self, 'package_path'):
@@ -60,9 +73,11 @@ class PluginLoader(object):
         return [self.package_path]
 
     def _get_paths(self):
-        """Return a list of paths to search for plugins in
+        ''' Return a list of paths to search for plugins in '''
+
+        if self._paths is not None:
+            return self._paths
 
-        The list is searched in order."""
         ret = []
         ret += self._extra_dirs
         for basedir in _basedirs:
@@ -71,41 +86,51 @@ class PluginLoader(object):
                 ret.append(fullpath)
         ret += self.config.split(os.pathsep)
         ret += self._get_package_path()
+
+        self._paths = ret
+
         return ret
 
+
     def add_directory(self, directory, with_subdir=False):
-        """Adds an additional directory to the search path"""
+        ''' Adds an additional directory to the search path '''
+
+        self._paths = None
+
         if directory is not None:
             if with_subdir:
                 directory = os.path.join(directory, self.subdir)
             self._extra_dirs.append(directory)
 
-    def print_paths(self):
-        """Returns a string suitable for printing of the search path"""
-        # Uses a list to get the order right
-        ret = []
-        for i in self._get_paths():
-            if i not in ret:
-                ret.append(i)
-        return os.pathsep.join(ret)
-
     def find_plugin(self, name):
-        """Find a plugin named name"""
+        ''' Find a plugin named name '''
+
+        if 'name' in self._plugin_path_cache:
+            return self._plugin_path_cache[name]
+
         suffix = ".py"
         if not self.class_name:
             suffix = ""
+        paths = self._get_paths()
+
         for i in self._get_paths():
             path = os.path.join(i, "%s%s" % (name, suffix))
             if os.path.exists(path):
+                self._plugin_path_cache[name] = path
                 return path
+
         return None
 
     def has_plugin(self, name):
-        """Checks if a plugin named name exists"""
+        ''' Checks if a plugin named name exists '''
+
         return self.find_plugin(name) is not None
+
     __contains__ = has_plugin
 
     def get(self, name, *args, **kwargs):
+        ''' instantiates a plugin of the given name using arguments '''
+
         if name in self.aliases:
             name = self.aliases[name]
         path = self.find_plugin(name)
@@ -116,7 +141,8 @@ class PluginLoader(object):
         return getattr(self._module_cache[path], self.class_name)(*args, **kwargs)
 
     def all(self, *args, **kwargs):
-       
+        ''' instantiates all plugins with the same arguments '''       
+
         for i in self._get_paths():
             for path in glob.glob(os.path.join(i, "*.py")):
                 name, ext = os.path.splitext(os.path.basename(path))