mic/pluginmgr.py

   1 #!/usr/bin/python -t
   2 import os
   3 import sys
   4 import logging
   5
   6 DEFAULT_PLUGIN_LOCATION = "/usr/lib/mic/plugins"
   7 DEFINED_PLGUIN_TYPES = ["imager", "backend", "hook"]
   8 STRING_PLUGIN_MARK = "mic_plugin"
   9 STRING_PTYPE_MARK = "plugin_type"
  10
  11 class PluginMgr(object):
  12     def __init__(self, plugin_dirs=[]):
  13         self.plugin_locations = []
  14         self.plugin_sets = {}
  15         self.plugin_types = DEFINED_PLGUIN_TYPES
  16         # initial plugin directory
  17         self.addPluginDir(DEFAULT_PLUGIN_LOCATION)
  18         for directory in plugin_dirs:
  19             self.addPluginDir(os.path.expanduser(directory))
  20         # intial plugin sets
  21         for plugintype in self.plugin_types:
  22             self.plugin_sets[plugintype] = []
  23
  24     def addPluginDir(self, plugin_dir=None):
  25         if not os.path.exists(plugin_dir):
  26             logging.debug("Directory already exists: %s" % plugin_dir)
  27             return
  28         if not os.path.isdir(plugin_dir):
  29             logging.debug("Not a directory: %s" % plugin_dir)
  30             return
  31         if not (plugin_dir in self.plugin_locations):
  32             self.plugin_locations.append(plugin_dir)
  33
  34     def pluginCheck(self, pymod):
  35         if not hasattr(pymod, STRING_PLUGIN_MARK):
  36             logging.debug("Not a valid plugin: %s" % pymod.__file__)
  37             logging.debug("Please check whether %s given" % STRING_PLUGIN_MARK)
  38             return False
  39         plclass = getattr(pymod, STRING_PLUGIN_MARK)[1]
  40         if not hasattr(plclass, STRING_PTYPE_MARK):
  41             logging.debug("Not a valid plugin: %s" % pymod.__file__)
  42             logging.debug("Please check whether %s given" % STRING_PTYPE_MARK)
  43             return False
  44         pltype = getattr(plclass, STRING_PTYPE_MARK)
  45         if not (pltype in self.plugin_types):
  46             logging.debug("Unsupported plugin type in %s: %s" % (pymod.__file__, plugintype))
  47             return False
  48         return True
  49
  50     def importModule(self, dir_path, plugin_filename):
  51         if plugin_filename.endswith(".pyc"):
  52             return
  53         if not plugin_filename.endswith(".py"):
  54             logging.debug("Not a python file: %s" % os.path.join(dir_path, plugin_filename))
  55             return
  56         if plugin_filename == "__init__.py":
  57             logging.debug("Unsupported python file: %s" % os.path.join(dir_path, plugin_filename))
  58             return
  59         modname = os.path.splitext(plugin_filename)[0]
  60         if sys.modules.has_key(modname):
  61             pymod = sys.modules[modname]
  62             logging.debug("Module %s already exists: %s" % (modname, pymod.__file__))
  63         else:
  64             pymod = __import__(modname)
  65             pymod.__file__ = os.path.join(dir_path, plugin_filename)
  66         if not self.pluginCheck(pymod):
  67             logging.warn("Failed to check plugin: %s" % os.path.join(dir_path, plugin_filename))
  68             return
  69         (pname, pcls) = pymod.__dict__[STRING_PLUGIN_MARK]
  70         plugintype = getattr(pcls, STRING_PTYPE_MARK)
  71         self.plugin_sets[plugintype].append((pname, pcls))
  72
  73     def loadPlugins(self):
  74         for pdir in map(os.path.abspath, self.plugin_locations):
  75             for pitem in os.walk(pdir):
  76                 sys.path.insert(0, pitem[0])
  77                 for pf in pitem[2]:
  78                     self.importModule(pitem[0], pf)
  79                 del(sys.path[0])
  80
  81     def getPluginByCateg(self, categ = None):
  82         if not (categ in self.plugin_types):
  83             logging.warn("Failed to get plugin category: %s" % categ)
  84             return None
  85         else:
  86             return self.plugin_sets[categ]
  87
  88     def getImagerPlugins(self):
  89         return self.plugin_sets['imager']
  90
  91     def getBackendPlugins(self):
  92         return self.plugin_sets['backend']
  93
  94     def getHookPlugins(self):
  95         return self.plugin_sets['hook']
  96
  97     def listAllPlugins(self):
  98         for key in self.plugin_sets.keys():
  99             sys.stdout.write("plugin type (%s) :::\n" % key)
 100             for item in self.plugin_sets[key]:
 101                 sys.stdout.write("%-6s: %s\n" % (item[0], item[1]))
 102
 103     def getPluginType(self, plugin_str):
 104         pass
 105
 106 if __name__ == "__main__":
 107     logging.getLogger().setLevel(logging.DEBUG)
 108
 109     pluginmgr = PluginMgr()
 110     pluginmgr.loadPlugins()
 111     pluginmgr.listAllPlugins()
 112