def __init__(self, auth_service, logger=None):
        self.__compute_nodes = {}
        self.__vm_instances = {}
        self.__services = {}
        self.__auth_service = auth_service
        self.__migrate_service = MigrateService(auth_service=auth_service, logger=logger)

        #   Filteri koji sluze za racunanje opterecenja
        self.__filters = {
            "ram": ram_filter.RamFilter(logger=logger),
            "vcpu": core_filter.CoreFilter(logger=logger),
            "disk": disk_filter.DiskFilter(logger=logger),
        }

        #   Fleg koji govori da li je potrebno izvrsiti algoritam za detekciju opterecenja
        self.__check_overload = False
        self.__task = None
        self.__lock = Lock()
        # objekat za upis u log fajl
        self.logger = logger or logging.getLogger(__name__)
class RabbitMQMessageService(object):
    """ Klasa zaduzena za parsiranje poruka, cuvanje informacija i detekciju opterecenja cvorova.
        Cuvaju se informacije o compute cvorovima, instancama i servisima.

    """

    def __init__(self, auth_service, logger=None):
        self.__compute_nodes = {}
        self.__vm_instances = {}
        self.__services = {}
        self.__auth_service = auth_service
        self.__migrate_service = MigrateService(auth_service=auth_service, logger=logger)

        #   Filteri koji sluze za racunanje opterecenja
        self.__filters = {
            "ram": ram_filter.RamFilter(logger=logger),
            "vcpu": core_filter.CoreFilter(logger=logger),
            "disk": disk_filter.DiskFilter(logger=logger),
        }

        #   Fleg koji govori da li je potrebno izvrsiti algoritam za detekciju opterecenja
        self.__check_overload = False
        self.__task = None
        self.__lock = Lock()
        # objekat za upis u log fajl
        self.logger = logger or logging.getLogger(__name__)

    def stop_periodic_check(self):
        """ Zaustavlja periodicno prikupljane informacija slanjem zahtjeva API serveru """
        if self.__task != None:
            self.logger.info("Periodic collectiong of data canceled")
            self.__task.cancel()
            self.__task = None

    def start_periodic_check(self):
        """ Pokrece periodicno prikupljane informacija slanjem zahtjeva API serveru """
        self.stop_periodic_check()
        self.__task = Timer(config.periodic_check_interval, self.__periodic_check)
        self.__task.setDaemon(True)
        self.__task.start()
        self.logger.info("Scheduled periodic check for %d sec" % config.periodic_check_interval)

    def initialize(self):
        """ Metoda za prikupljanje informacija slanjem zahtjeav API serveru """
        self.__lock.acquire()
        try:
            self.logger.sys_info("Initializing RabbitMQMessageService")
            novaclient = client.Client(
                self.__auth_service.get_nova_api_version(), session=self.__auth_service.get_session()
            )
            self.logger.info("Collecting information about compute nodes")
            hypervisors = novaclient.hypervisors.list(detailed=True)
            self.logger.info("Collecting information about services")
            services = novaclient.services.list()
            self.logger.info("Collecting information about VMs")
            servers = novaclient.servers.list(detailed=True)
            self.logger.info("Processing collected data")

            init_services = {}
            init_compute_nodes = {}
            init_vm_instances = {}

            for service in services:
                service = service.to_dict()
                service_node = Service()
                service_node.id = service["id"]
                service_node.binary = service["binary"]
                service_node.created_at = service["updated_at"]
                service_node.disabled = service["status"]
                service_node.host = service["host"]
                service_node.topic = service["binary"]

                init_services[service_node.id] = service_node

            for hypervisor in hypervisors:
                hypervisor = hypervisor.to_dict()
                node = ComputeNode()
                node.id = hypervisor["id"]
                node.free_disk_gb = hypervisor["free_disk_gb"]
                node.free_ram_mb = hypervisor["free_ram_mb"]
                node.host_ip = hypervisor["host_ip"]
                node.hypervisor_hostname = hypervisor["hypervisor_hostname"]
                node.hypervisor_type = hypervisor["hypervisor_type"]
                node.local_gb = hypervisor["local_gb"]
                node.local_gb_used = hypervisor["local_gb_used"]
                node.memory_mb = hypervisor["memory_mb"]
                node.memory_mb_used = hypervisor["memory_mb_used"]
                node.running_vms = hypervisor["running_vms"]
                node.service_id = hypervisor["service"]["id"]
                node.host = hypervisor["service"]["host"]
                node.vcpus = hypervisor["vcpus"]
                node.vcpus_used = hypervisor["vcpus_used"]

                node.state = hypervisor["state"]
                node.status = hypervisor["status"]

                self.__calculate_node_overload_and_weight(node)
                init_compute_nodes[node.id] = node

            for server in servers:
                server = server.to_dict()
                vm_id = server["id"]
                if vm_id in self.__vm_instances.keys():
                    vm_instance = self.__vm_instances[vm_id]
                    vm_instance.hostname = server["name"]
                    vm_instance.availability_zone = server["OS-EXT-AZ:availability_zone"]
                    vm_instance.new_task_state = server["OS-EXT-STS:task_state"]
                    vm_instance.state = server["OS-EXT-STS:vm_state"]
                    vm_instance.host = server["OS-EXT-SRV-ATTR:host"]
                else:
                    vm_instance = VMInstance()
                    vm_instance.id = vm_id
                    vm_instance.availability_zone = server["OS-EXT-AZ:availability_zone"]
                    vm_instance.created_at = server["OS-SRV-USG:launched_at"]
                    vm_instance.display_name = server["name"]
                    vm_instance.host = server["OS-EXT-SRV-ATTR:host"]
                    vm_instance.hostname = server["name"]
                    vm_instance.new_task_state = server["OS-EXT-STS:task_state"]
                    vm_instance.state = server["OS-EXT-STS:vm_state"]
                    vm_instance.tenant_id = server["tenant_id"]
                    vm_instance.user_id = server["user_id"]

                    vm_instance.instance_flavor_id = server["flavor"]["id"]
                    flavor = novaclient.flavors.get(flavor=vm_instance.instance_flavor_id)
                    flavor = flavor.to_dict()
                    vm_instance.instance_flavor = flavor["name"]
                    vm_instance.disk_gb = flavor["disk"]
                    vm_instance.ephemeral_gb = flavor["OS-FLV-EXT-DATA:ephemeral"]
                    vm_instance.vcpus = flavor["vcpus"]
                    vm_instance.memory_mb = flavor["ram"]

                    image_meta = novaclient.images.get(image=server["image"]["id"])
                    image_meta = image_meta.to_dict()
                    vm_instance.image_meta.min_disk = image_meta["minDisk"]
                    vm_instance.image_meta.min_ram = image_meta["minRam"]

                init_vm_instances[vm_instance.id] = vm_instance

            self.__services = init_services
            self.__compute_nodes = init_compute_nodes
            self.__vm_instances = init_vm_instances
            for instance in self.__vm_instances.values():
                self.__process_vm_instance(vm_instance=instance)

            self.print_short_info()

            self.__check_overload = True
            self.__lock.release()
            return True

        except from_response as e:
            self.logger.error(e)
            self.logger.exception(e)
            self.__lock.release()
            return False
        except Exception as e:
            self.logger.error(e)
            self.logger.exception(e)
            self.__lock.release()
            return False

    def parse_message(self, routing_key, message):
        """ Metoda za parsiranje poruka """
        self.__lock.acquire()
        # uklanja wrapper oslo.message in json
        message = json.loads(message)
        while "oslo.message" in message:
            message = json.loads(message["oslo.message"])
        if routing_key == "conductor":
            self.__parse_conductor_message(message)
        elif routing_key == "notifications.info":
            self.__parse_notification_info_message(message)

        self.__lock.release()

    def find_service_by_host(self, host):
        for service in self.__services.values():
            if service.host == host:
                return service
        return None

    def find_node_by_service_id(self, service_id):
        for node in self.__compute_nodes.values():
            if node.service_id == service_id:
                return node
        return None

    def find_node_by_hostname(self, hostname):
        for node in self.__compute_nodes.values():
            if node.hypervisor_hostname == hostname:
                return node
        return None

    def add_vm_instance_to_node(self, vm_instance):
        """ Pronalazi cvor i dodaje instancu u njegovu listu instanci """
        service = self.find_service_by_host(vm_instance.host)
        if service is not None:
            node = self.find_node_by_service_id(service.id)
            if node is not None:
                vm_instance.compute_node = node
                node.vm_instances[vm_instance.id] = vm_instance
                return True
        return False

    def check_overload(self):
        """ Metoda za detekciju opterecenja """
        self.__lock.acquire()
        if self.__check_overload == False or len(self.__compute_nodes) == 0:
            self.__lock.release()
            return
        else:
            self.logger.debug("Sorting hosts overload")
            values = self.__get_hosts_ordered()
            overloaded = values[0]
            underloaded = values[1]
            node = None
            self.logger.debug("Searching for the most overloaded host")
            for host in overloaded:
                if host.is_free_to_migrate_instances():
                    node = host
                    self.logger.debug("Found host %s" % (host.hypervisor_hostname))
                    break
                self.logger.debug("Skipping host %s , it has migrating instances" % host.hypervisor_hostname)
            if node == None:
                self.logger.info("Not available host")
                self.__check_overload = False
                self.__lock.release()
                return

            vms = node.vm_instances.values()
            vms.sort(key=operator.attrgetter("memory_mb"))

            overloaded_weight = node.metrics_weight

            for vm in vms:
                mig_time = vm.last_migrate_time
                if vm.is_ready_for_migrating() and (mig_time == None or ((time() - mig_time) > ALLOW_MIGRATE_TIME)):
                    self.logger.debug("Found instance to migrate %s" % vm.display_name)
                    for migrate_node in underloaded:
                        vm_weight_on_migrate = 0
                        vm_weight_on_overloaded = 0
                        passes = True
                        for filt in self.__filters.values():
                            vm_weight_on_migrate += filt.weight_instance_on_host(migrate_node, vm)
                            vm_weight_on_overloaded += filt.weight_instance_on_host(node, vm)
                            passes = passes and filt.filter_one(migrate_node, vm)
                        if passes == True:
                            total_weight = float(
                                "{0:.2f}".format(migrate_node.metrics_with_migrating_vms + vm_weight_on_migrate)
                            )
                            check_weight = float("{0:.2f}".format(overloaded_weight - vm_weight_on_overloaded))
                            self.logger.sys_info("WW: %s WO: %s" % (total_weight, check_weight))
                            if total_weight <= check_weight:
                                scheduled = self.__migrate_service.schedule_live_migration(vm.id, migrate_node)
                                if scheduled == True:
                                    self.logger.sys_info("Migrate scheduling passed ")
                                    migrate_node.metrics_with_migrating_vms = total_weight
                                    self.__check_overload = False
                                    self.__lock.release()
                                    return

            self.__check_overload = False
            self.__lock.release()

    def __get_hosts_ordered(self):
        """ Racuna srednju vrijednost opterecenja i sortira hostove u odgovarajucim listama """
        hosts = []
        average_weight = 0
        for node in self.__compute_nodes.values():
            if node.is_running():
                hosts.append(node)
                average_weight += node.metrics_weight
        if len(hosts) == 0:
            return ([], [])
        average_weight = (average_weight * 1.0) / len(hosts)
        overloaded = []
        underloaded = []
        for host in hosts:
            if host.are_data_synced():
                if host.metrics_weight > average_weight:
                    overloaded.append(host)
                else:
                    self.__calculate_node_overload_and_weight(host)
                    underloaded.append(host)
        overloaded.sort(key=operator.attrgetter("metrics_weight"), reverse=True)
        underloaded.sort(key=operator.attrgetter("metrics_with_migrating_vms"))

        return (overloaded, underloaded)

    @property
    def migrate_service(self):
        return self.__migrate_service

    @migrate_service.setter
    def migrate_service(self, service):
        self.__migrate_service = service

    @property
    def compute_nodes_list(self):
        return self.__compute_nodes.values()

    @property
    def vm_instances_list(self):
        return self.__vm_instances.values()

    @property
    def services_list(self):
        return self.__services.values()

    def print_all_info(self):
        for node in self.__compute_nodes.values():
            node.print_info()

        for vm_instance in self.__vm_instances.values():
            vm_instance.print_info()
            vm_instance.image_meta.print_info()

        for service in self.__services.values():
            service.print_info()

    def print_short_info(self):
        self.logger.total_info("Total: %d vms" % len(self.__vm_instances))
        for node in self.__compute_nodes.values():
            self.logger.node_info(
                "%s: %d State: %s %s" % (node.hypervisor_hostname, len(node.vm_instances), node.state, node.status)
            )

    def __calculate_node_overload_and_weight(self, node):
        """ Racuna opterecenje na compute cvorovima """
        weight = 0
        overloaded = False
        for filt in self.__filters.values():
            weight += filt.weight_host(host=node)
            overloaded = overloaded or filt.overloaded(host=node)
        node.metrics_weight = weight
        node.overloaded = overloaded
        node.metrics_with_migrating_vms = node.metrics_weight
        # vraca ID-ove instacni koje se trenutno migriraju na hosta i racuna opterenja
        migrating_vm_ids = self.__migrate_service.get_migrating_vms_to_host(node.id)
        for vm_id in migrating_vm_ids:
            vm = self.__vm_instances[vm_id]
            vm_weight = 0
            for filt in self.__filters.values():
                vm_weight += filt.weight_instance_on_host(host=node, vm=vm)
            node.metrics_with_migrating_vms += vm_weight
        self.logger.sys_info(
            "%s MW: %s MWMI: %s" % (node.hypervisor_hostname, node.metrics_weight, node.metrics_with_migrating_vms)
        )

    def __parse_conductor_message(self, message):
        """ Pomocna metoda za parsiranje poruka sa 'conductor' kljucem za rutiranje
            Postoji vise formata ove poruke. Format poruke se moze razlikovati na osnovu 'method' parametra u poruci.
        """
        parsed_json = message
        method = parsed_json["method"]
        if method == "compute_node_update":
            node_id = parsed_json["args"]["node"]["id"]
            if node_id in self.__compute_nodes.keys():
                node = self.__compute_nodes[node_id]
            else:
                node = ComputeNode()
            node.project_name = parsed_json.get("_context_project_name", "")
            node.id = node_id
            values = parsed_json.get("args", {}).get("values", {})
            node.created_at = values.get("created_at", "")
            node.free_disk_gb = values.get("free_disk_gb", -1)
            node.free_ram_mb = values.get("free_ram_mb", -1)
            node.host_ip = values.get("host_ip", "")
            node.hypervisor_hostname = values.get("hypervisor_hostname", "")
            node.hypervisor_type = values.get("hypervisor_type", "")
            node.local_gb = values.get("local_gb", -1)
            node.local_gb_used = values.get("local_gb_used", -1)
            node.memory_mb = values.get("memory_mb", -1)
            node.memory_mb_used = values.get("memory_mb_used", -1)
            node.running_vms = values.get("running_vms", -1)
            node.service_id = values.get("service_id", node.service_id)
            node.vcpus = values.get("vcpus", -1)
            node.vcpus_used = values.get("vcpus_used", -1)

            self.__calculate_node_overload_and_weight(node=node)
            self.__compute_nodes[node.id] = node

            self.__check_overload = True

            self.print_short_info()

        elif method == "service_update":
            parsed_json = message
            service_dict = parsed_json.get("args", {}).get("service", {})
            service_id = service_dict["id"]
            if service_id in self.__services.keys():
                service_obj = self.__services[service_id]
            else:
                service_obj = Service()
            service_obj.id = service_id
            service_obj.binary = service_dict["binary"]
            service_obj.created_at = service_dict["created_at"]
            service_obj.disabled = service_dict["disabled"]
            service_obj.host = service_dict["host"]
            service_obj.topic = service_dict["topic"]

            self.__services[service_id] = service_obj

    def __parse_notification_info_message(self, message):
        """ Pomocna metoda za parsiranje poruka sa 'notification.info' kljucem za rutiranje """
        parsed_json = message
        event_type = parsed_json["event_type"]
        if event_type == "compute.instance.update":
            payload = parsed_json["payload"]
            vm_id = payload["instance_id"]
            if vm_id in self.__vm_instances.keys():
                vm_instance = self.__vm_instances[vm_id]
            else:
                vm_instance = VMInstance()

            vm_instance.project_name = parsed_json["_context_project_name"]
            vm_instance.id = vm_id
            vm_instance.availability_zone = payload.get("availability_zone", "")
            vm_instance.created_at = payload.get("created_at", "")
            vm_instance.disk_gb = payload.get("disk_gb", -1)
            vm_instance.display_name = payload.get("display_name", -1)
            vm_instance.ephemeral_gb = payload.get("ephemeral_gb", -1)
            vm_instance.host = payload.get("host", "")
            vm_instance.hostname = payload.get("hostname", "")
            vm_instance.vcpus = payload.get("vcpus", -1)
            vm_instance.instance_flavor = payload.get("instance_type", "")
            vm_instance.instance_flavor_id = payload.get("instance_flavor_id", -1)

            image_meta = payload.get("image_meta", {})
            vm_instance.image_meta.base_image_ref = image_meta.get("base_image_ref", "")
            vm_instance.image_meta.container_format = image_meta.get("container_format", "")
            vm_instance.image_meta.disk_format = image_meta.get("disk_format", "")
            vm_instance.image_meta.min_disk = image_meta.get("min_disk", -1)
            vm_instance.image_meta.min_ram = image_meta.get("min_ram", -1)

            vm_instance.hypervisor_hostname = payload.get("node", "")
            vm_instance.memory_mb = payload.get("memory_mb", -1)
            vm_instance.os_type = payload.get("os_type", -1)
            vm_instance.state = payload.get("state", "")
            vm_instance.old_state = payload.get("old_state", "")
            vm_instance.new_task_state = payload.get("new_task_state", "")
            vm_instance.old_task_state = payload.get("old_task_state", "")
            vm_instance.tenant_id = payload.get("tenant_id", -1)
            vm_instance.user_id = payload.get("user_id", -1)

            self.__vm_instances[vm_id] = vm_instance

            self.__process_vm_instance(vm_instance)

            self.print_short_info()

    def __process_vm_instance(self, vm_instance):
        """ Metoda koja izvrsava odgovarajuce akcije u zavisnosti od toga u kakvom je stanju instanca.
            Poziva se poslije obrade poruke o instanci
        """
        self.logger.vm_info(
            "Host: %s Name: %s State: %s New_task: %s"
            % (vm_instance.host, vm_instance.display_name, vm_instance.state, vm_instance.new_task_state)
        )

        if vm_instance.is_active():
            if vm_instance.has_started_to_migrate():
                self.logger.migration_started("Host: %s Instance: %s" % (vm_instance.host, vm_instance.display_name))
                vm_instance.last_migrate_time = time()

        elif vm_instance.is_deleted():
            if vm_instance.id in self.__vm_instances.keys():
                del self.__vm_instances[vm_instance.id]
            if vm_instance.compute_node is not None:
                vm_instance.compute_node.remove_from_vm_instances(vm_instance.id)

        elif vm_instance.is_in_error_state():
            self.logger.warning("Instance %s is in error state" % (vm_instance.display_name))
            if vm_instance.compute_node is None:
                self.logger.warning("Instance %s is not spawned on any node" % (vm_instance.display_name))

        if vm_instance.compute_node is not None:
            vm_instance.compute_node.remove_from_vm_instances(vm_instance.id)

        if not vm_instance.is_deleted():
            self.add_vm_instance_to_node(vm_instance)

        if vm_instance.has_migrated():
            self.__migrate_service.task_done(vm_instance.id)

    def __periodic_check(self):
        """ Pomocna metoda koju pokrece tajmer za periodicno prikupljanje informacija  """
        self.initialize()
        self.__task = Timer(config.periodic_check_interval, self.__periodic_check)
        self.__task.setDaemon(True)
        self.__task.start()
        self.logger.info("Scheduled periodic check for %d sec" % config.periodic_check_interval)