Synnefo

#!/usr/bin/env python

#

# Copyright (c) 2010 Greek Research and Technology Network

#

"""Receive Ganeti events over 0mq, update VM state in DB.

This daemon receives job notifications from ganeti-0mqd

and updates VM state in the DB accordingly.

"""

from django.core.management import setup_environ

import sys

import os

path = os.path.normpath(os.path.join(os.getcwd(), '..'))

sys.path.append(path)

import synnefo.settings as settings

setup_environ(settings)

import zmq

import time

import json

import platform

import logging

import getpass

import traceback

from threading import Thread, Event, currentThread

from synnefo.db.models import VirtualMachine

from synnefo.settings import GANETI_ZMQ_PUBLISHER

from synnefo.logic import utils, backend

class StoppableThread(Thread):

    """Thread class with a stop() method.

    The thread needs to check regularly for the stopped() condition.

    When it does, it exits, so that another thread may .join() it.

    """

    def __init__(self, *args, **kwargs):

        super(StoppableThread, self).__init__(*args, **kwargs)

        self._stop = Event()

    def stop(self):

        self._stop.set()

    def stopped(self):

        return self._stop.isSet()

def zmq_sub_thread(subscriber):

    while True:

        logging.debug("Entering 0mq to wait for message on SUB socket.")

        data = subscriber.recv()

        logging.debug("Received message on 0mq SUB socket.")

        try:

            msg = json.loads(data)

            if currentThread().stopped():

                logging.debug("Thread has been stopped, leaving request loop.")

                return

            if msg["type"] != "ganeti-op-status":

                logging.debug("Ignoring message of uknown type %s." % (msg["type"],))

                continue

            vmid = utils.id_from_instance_name(msg["instance"])

            vm = VirtualMachine.objects.get(id=vmid)

            logging.debug("Processing msg: %s" % (msg,))

            backend.process_backend_msg(vm, msg["jobId"], msg["operation"], msg["status"], msg["logmsg"])

            logging.debug("Done processing msg for vm %s." % (msg["instance"]))

        except KeyError:

            logging.error("Malformed incoming JSON, missing attributes: " + data)

        except VirtualMachine.InvalidBackendIdError:

            logging.debug("Ignoring msg for unknown instance %s." % (msg["instance"],))

        except VirtualMachine.DoesNotExist:

            logging.error("VM for instance %s with id %d not found in DB." % (msg["instance"], vmid))

        except Exception as e:

            logging.error("Unexpected error:\n" + "".join(traceback.format_exception(*sys.exc_info())))

            continue

def main():

    # Create an inproc PUB socket, for inter-thread communication

    zmqc = zmq.Context()

    inproc = zmqc.socket(zmq.PUB)

    inproc.bind("inproc://threads")

    #

    # Create a SUB socket, connect to ganeti-0mqd and the inproc PUB socket

    #

    subscriber = zmqc.socket(zmq.SUB)

    # Combine the hostname, username and a constant string to get

    # a hopefully unique identity for this 0mq peer.

    # Reusing zmq.IDENTITY for two distinct peers triggers this 0mq bug:

    # https://github.com/zeromq/zeromq2/issues/30

    subscriber.setsockopt(zmq.IDENTITY, platform.node() + getpass.getuser() + "snf-db-controller")

    subscriber.setsockopt(zmq.SUBSCRIBE, "")

    subscriber.connect(GANETI_ZMQ_PUBLISHER)

    subscriber.connect("inproc://threads")

    # Use a separate thread to process incoming messages,

    # needed because the Python runtime interacts badly with 0mq's blocking semantics.

    zmqt = StoppableThread(target = zmq_sub_thread, args = (subscriber,))

    zmqt.start()

    try:

        logging.info("in main thread.");

        while True:

            logging.info("When I grow up, I'll be syncing with Ganeti at this point.")

            time.sleep(600)

    except:

        logging.error("Caught exception:\n" + "".join(traceback.format_exception(*sys.exc_info())))

        #

        # Cleanup.

        #

        # Cancel the suscriber thread, wake it up, then join it.

        zmqt.stop()

        inproc.send_json({"type":"null"})

        zmqt.join()

        return 1

if __name__ == "__main__":

    logging.basicConfig(level=logging.DEBUG)

    sys.exit(main())

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