mod_plugins.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import imp
import os
import re
import sys

import mod_logger
log = mod_logger.initlog(__name__)

RE_PLUGIN_FILE = re.compile("^([^\.]+)\.py$")

found    = dict()
quorum   = False
switcher = False
notifier = False

def search(plugin_dir):
    global found

    for subdir in os.listdir(plugin_dir):
        if not os.path.isdir(os.path.join(plugin_dir, subdir)):
            continue

        for filename in os.listdir(os.path.join(plugin_dir, subdir)):
            if not os.path.isfile(os.path.join(plugin_dir, subdir, filename)):
                continue

            match = RE_PLUGIN_FILE.match(filename)

            if match:
                plugin_type = subdir
                plugin_name = match.group(1)
                plugin_desc = imp.find_module(plugin_name, [os.path.join(plugin_dir, plugin_type)])

                if not found.has_key(plugin_type):
                    found[plugin_type] = dict()

                found[plugin_type][plugin_name] = plugin_desc

    return found

def load(plugin_type, plugin_name):
    global found

    if not found:
        log.fatal("Plugins detection has not been done, please call plugins.search(plugin_dir) first.\n")
        return False

    if found.has_key(plugin_type) and found[plugin_type].has_key(plugin_name):
        return imp.load_module("%s_%s" % (plugin_type, plugin_name), *found[plugin_type][plugin_name])

    return False

def loadQuorum(quorum_plugin):
    global quorum

    # load quorum plugin if any
    if quorum_plugin:
        quorum = load("quorum", quorum_plugin) or log.fatal("Failed to load quorum plugin '%s'" % (quorum_plugin))

def loadSwitcher(switcher_plugin):
    global switcher

    # load switcher plugin if any
    if switcher_plugin:
        switcher = load("switcher", switcher_plugin) or log.fatal("Failed to load switcher plugin '%s'" % (switcher_plugin))

def loadNotifier(notifier_plugin):
    global notifier

    # load notifier plugin if any
    if notifier_plugin:
        notifier = load("notifier", notifier_plugin) or log.fatal("Failed to load notifier plugin '%s'" % (notifier_plugin))

def show():
    global found

    if not found:
        sys.stderr.write("Plugins detection has not been done, please call plugins.search(plugin_dir) first.\n")
        return False

    print "Found plugins :"

    for plugin_type in found.keys():
        print "    %s :" % (plugin_type.title())
        for plugin_name in found[plugin_type].keys():
            print "        %s -- %s" % (plugin_name, found[plugin_type][plugin_name][1])
        print

    return True