Synnefo

# Copyright 2011 GRNET S.A. All rights reserved.

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# those of the authors and should not be interpreted as representing official

# policies, either expressed or implied, of GRNET S.A.

# Callback functions used by the dispatcher to process incoming notifications

# from AMQP queues.

import logging

import json

from functools import wraps

from synnefo.db.models import Backend, VirtualMachine, Network, BackendNetwork

from synnefo.logic import utils, backend

from synnefo.lib.utils import merge_time

log = logging.getLogger()

def handle_message_delivery(func):

    """ Generic decorator for handling messages.

    This decorator is responsible for converting the message into json format,

    handling of common exceptions and acknowledment of message if needed.

    """

    @wraps(func)

    def wrapper(client, message, *args, **kwargs):

        try:

            msg = json.loads(message['body'])

            func(msg)

            client.basic_ack(message)

        except ValueError as e:

            log.error("Incoming message not in JSON format %s: %s", e, message)

            client.basic_ack(message)

        except KeyError as e:

            log.error("Malformed incoming JSON, missing attribute %s: %s",

                      e, message)

            client.basic_ack(message)

        except Exception as e:

            log.exception("Unexpected error: %s, msg: %s", e, msg)

    return wrapper

def instance_from_msg(func):

    """ Decorator for getting the VirtualMachine object of the msg.

    """

    @handle_message_delivery

    @wraps(func)

    def wrapper(msg):

        try:

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

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

            func(vm, msg)

        except VirtualMachine.InvalidBackendIdError:

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

        except VirtualMachine.DoesNotExist:

            log.error("VM for instance %s with id %d not found in DB.",

                      msg['instance'], vm_id)

        except Network.InvalidBackendIdError, Network.DoesNotExist:

            log.error("Invalid message", msg)

    return wrapper

def network_from_msg(func):

    """ Decorator for getting the BackendNetwork object of the msg.

    """

    @handle_message_delivery

    @wraps(func)

    def wrapper(msg):

        try:

            network_id = utils.id_from_network_name(msg["network"])

            network = Network.objects.select_for_update().get(id=network_id)

            backend = Backend.objects.get(clustername=msg['cluster'])

            backend_network = BackendNetwork.objects.get(network=network,

                                                         backend=backend)

            func(backend_network, msg)

        except Network.InvalidBackendIdError:

            log.debug("Ignoring msg for unknown network %s.", msg['network'])

        except Network.DoesNotExist:

            log.error("Network %s not found in DB.", msg['network'])

        except Backend.DoesNotExist:

            log.error("Backend %s not found in DB.", msg['cluster'])

        except BackendNetwork.DoesNotExist:

            log.error("Network %s on backend %s not found in DB.",

                      msg['network'], msg['cluster'])

    return wrapper

def if_update_required(func):

    """

    Decorator for checking if an incoming message needs to update the db.

    The database will not be updated in the following cases:

    - The message has been redelivered and the action has already been

      completed. In this case the event_time will be equal with the one

      in the database.

    - The message describes a previous state in the ganeti, from the one that

      is described in the db. In this case the event_time will be smaller from

      the one in the database.

    """

    @wraps(func)

    def wrapper(target, msg):

        try:

            event_time = merge_time(msg['event_time'])

        except:

            log.error("Received message with malformed time: %s",

                      msg['event_time'])

            raise KeyError

        db_time = target.backendtime

        if db_time and event_time <= db_time:

            format_ = "%d/%m/%y %H:%M:%S:%f"

            log.debug("Ignoring message %s.\nevent_timestamp: %s db_timestamp: %s",

                      msg,

                      event_time.strftime(format_),

                      db_time.strftime(format_))

            return

        # New message. Update the database!

        func(target, msg, event_time)

    return wrapper

@instance_from_msg

@if_update_required

def update_db(vm, msg, event_time):

    """Process a notification of type 'ganeti-op-status'"""

    log.debug("Processing ganeti-op-status msg: %s", msg)

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

        log.error("Message is of unknown type %s.", msg['type'])

        return

    backend.process_op_status(vm, event_time, msg['jobId'], msg['operation'],

                              msg['status'], msg['logmsg'])

    log.debug("Done processing ganeti-op-status msg for vm %s.",

              msg['instance'])

@instance_from_msg

@if_update_required

def update_net(vm, msg, event_time):

    """Process a notification of type 'ganeti-net-status'"""

    log.debug("Processing ganeti-net-status msg: %s", msg)

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

        log.error("Message is of unknown type %s", msg['type'])

        return

    backend.process_net_status(vm, event_time, msg['nics'])

    log.debug("Done processing ganeti-net-status msg for vm %s.",

              msg["instance"])

@network_from_msg

@if_update_required

def update_network(network, msg, event_time):

    """Process a notification of type 'ganeti-network-status'"""

    log.debug("Processing ganeti-network-status msg: %s", msg)

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

        log.error("Message is of unknown type %s.", msg['type'])

        return

    backend.process_network_status(network, event_time,

                                   msg['jobId'], msg['operation'],

                                   msg['status'], msg['logmsg'])

    log.debug("Done processing ganeti-network-status msg for network %s.",

              msg['network'])

@instance_from_msg

@if_update_required

def update_build_progress(vm, msg, event_time):

    """Process a create progress message"""

    log.debug("Processing ganeti-create-progress msg: %s", msg)

    if msg['type'] != "ganeti-create-progress":

        log.error("Message is of unknown type %s", msg['type'])

        return

    backend.process_create_progress(vm, event_time, msg['rprogress'], None)

    log.debug("Done processing ganeti-create-progress msg for vm %s.",

              msg['instance'])

def dummy_proc(client, message, *args, **kwargs):

    try:

        log.debug("Msg: %s", message['body'])

        client.basic_ack(message)

    except Exception as e:

        log.exception("Could not receive message %s" % e)