commit: c7b86d60b7c32f5bc858a428547e175eab579967
Author: Devan Franchini <twitch153 <AT> gentoo <DOT> org>
AuthorDate: Tue Jul 29 00:05:59 2014 +0000
Commit: Devan Franchini <twitch153 <AT> gentoo <DOT> org>
CommitDate: Fri Aug 15 21:42:41 2014 +0000
URL:
http://git.overlays.gentoo.org/gitweb/?p=proj/layman.git;a=commit;h=c7b86d60
module.py: Adds modular plugin system
---
layman/module.py | 211 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 211 insertions(+)
diff --git a/layman/module.py b/layman/module.py
new file mode 100644
index 0000000..6d7a40b
--- /dev/null
+++ b/layman/module.py
@@ -0,0 +1,211 @@
+# Copyright 2014 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+from __future__ import print_function
+
+import os
+
+from layman.output import Message
+
+class InvalidModuleName(Exception):
+ '''An invalid or unknown module name.'''
+
+class Module(object):
+ '''
+ Class to define and hold our plugin-module
+
+ @type name: string
+ @param name: The module name
+ @type namepath: string
+ @param namepath: The path to the new module
+ @param output: The output for any information
+ '''
+ def __init__(self, name, namepath, output):
+ self.name = name
+ self._namepath = namepath
+ self.kids_names = []
+ self.kids = {}
+ self.output = output
+ self.initialized = self._initialize()
+
+
+ def _initialize(self):
+ '''
+ Initializes the plug-in module
+
+ @rtype bool: reflects success or failure to initialize the module
+ '''
+ self.valid = False
+ try:
+ mod_name = '.'.join([self._namepath, self.name])
+ self._module = __import__(mod_name, [], [], ['not empty'])
+ self.valid = True
+ except ImportError as e:
+ self.output.error('Module._initialize(); failed to import %(mod) '\
+ 'error was: %(err)' % ({'err': e, 'mod': mod_name}))
+ return False
+ self.module_spec = self._module.module_spec
+ for submodule in self.module_spec['provides']:
+ kid = self.module_spec['provides'][submodule]
+ kidname = kid['name']
+ kid['module_name'] = '.'.join([mod_name, self.name])
+ kid['is_imported'] = False
+ self.kids[kidname] = kid
+ self.kids_names.append(kidname)
+ return True
+
+
+ def get_class(self, name):
+ '''
+ Retrieves a module class desired
+
+ @type name: string
+ @param name: the plug-in module's name
+ @rtype mod_class: instance of plug-in module's class
+ '''
+ if not name or name not in self.kids_names:
+ raise InvalidModuleName('Module name "%(name)" was invalid or not'\
+ 'part of the module "%(mod_name)"' ({'mod_name':self.name,
+ 'name': name}))
+ kid = self.kids[name]
+ if kid['is_imported']:
+ module = kid['instance']
+ else:
+ try:
+ module = __import__(kid['module_name'], [], [], ["not empty"])
+ kid['instance'] = module
+ kid['is_imported'] = True
+ except ImportError:
+ raise
+ mod_class = getattr(module, kid['class'])
+ return mod_class
+
+
+class Modules(object):
+ '''
+ Dynamic module system for loading and retrieving any of the
+ installed layman modules and/or provided class'
+
+ @param path: Optional path to the "modules" directory or defaults to
+ the directory of this file + "/modules"
+ @param namepath: Optional python import path to the "modules" directory or
+ defaults to the directory name of this file + ".modules"
+ @param output: Optional output, defaults to layman.output.Message object
+ '''
+ def __init__(self, path=None, namepath=None, output=None):
+ if path:
+ self._module_path = path
+ else:
+ self._module_path = os.path.join(
+ (os.path.dirname(os.path.realpath(__file__))), 'modules')
+ if namepath:
+ self._namepath = namepath
+ else:
+ self._namepath = '.'.join(os.path.dirname(
+ os.path.realpath(__file__)), 'modules')
+ if output:
+ self.output = output
+ else:
+ self.output = Message()
+ self._modules = self._get_all_modules()
+ self.module_names = sorted(self._modules)
+
+
+ def _get_all_modules(self):
+ '''
+ Scans the overlay modules dir for loadable modules
+
+ @rtype dict of module_plugins
+ '''
+ module_dir = self._module_path
+ importables = []
+ names = os.listdir(module_dir)
+ for entry in names:
+ if entry.startswith('__'):
+ continue
+ try:
+ os.lstat(os.path.join(module_dir, entry, '__init__.py'))
+ importables.append(entry)
+ except EnvironmentError:
+ pass
+
+ kids = {}
+ for entry in importables:
+ new_module = Module(entry, self._namepath, self.output)
+ for module_name in new_module.kids:
+ kid = new_module.kids[module_name]
+ kid['parent'] = new_module
+ kids[kid['name']] = kid
+ return kids
+
+
+ def get_module_names(self):
+ '''
+ Retrieves all available module names
+
+ @rtype: list of installed module names available
+ '''
+ return self.module_names
+
+
+ def get_class(self, modname):
+ '''
+ Retrieves a module class desired
+
+ @type modname: string
+ @param modname: the module class name
+ '''
+ if modname and modname in self.module_names:
+ mod = self._modules[modname]['parent'].get_class(modname)
+ else:
+ raise InvalidModuleName('Module name "%(name)s" was invalid or'\
+ ' not found.' % ({'name': modname}))
+ return mod
+
+
+ def get_description(self, modname):
+ '''
+ Retrieves the module class decription
+
+ @type modname: string
+ @param modname: the module class name
+ @rtype: string of modules class decription
+ '''
+ if modname and modname in self.module_names:
+ mod = self._modules[modname]['description']
+ else:
+ raise InvalidModuleName('Module name "%(name)s" was invalid or'\
+ ' not found.' % ({'name': modname}))
+ return mod
+
+
+ def get_functions(self, modname):
+ '''
+ Retrieves the module class exported function names
+
+ @type modname: string
+ @param modname: the module class name
+ @rtype: list of the modules class exported function names
+ '''
+ if modname and modname in self.module_names:
+ mod = self._modules[modname]['functions']
+ else:
+ raise InvalidModuleName('Module name "%(name)s" was invalid or'\
+ ' not found.' % ({'name': modname}))
+ return mod
+
+
+ def get_func_descriptions(self, modname):
+ '''
+ Retrieves the module class exported functions descriptions
+
+ @type modname: string
+ @param modname: the module class name
+ @rtype: dict of the modules class exported functions descriptions
+ '''
+ if modname and modname in self.module_names:
+ desc = self._modules[modname]['func_desc']
+ else:
+ raise InvalidModuleName('Module name "%(name)s" was invalid or'\
+ ' not found.' % ({'name': modname}))
+ return desc
