OpServ-Monitoring/opserv-backend

"""
    This module contains the queue manager which initalizes, handles and exposes 
    most of the communication functionality between server and gathering thread
"""

from queue import Queue

from misc.constants import QUEUEMANAGER_DEFAULT_TIMEOUT
from misc.opserv_helper import check_comp_args

request_data_queue = None
set_gathering_rate_queue = None

realtime_queues = None


def init():
    """
        Initializes the queue manager
    """
    global request_data_queue
    global set_gathering_rate_queue
    global realtime_queues

    request_data_queue = Queue()
    set_gathering_rate_queue = Queue()

    realtime_queues = {
        "cpu": {},
        "cpucore": {},
        "gpu": {},
        "memory": {},
        "disk": {},
        "partition": {},
        "process": {},
        "network": {},
        "system": {}
    }


def get_queue(component, metric, args=None):
    """ Returns either the requested queue or creates a new one """
    args = check_comp_args(realtime_queues, component, args)

    create_queue_if_not_exists(component, metric, args)

    if args is not None:
        return realtime_queues[component][args][metric]
    else:
        return realtime_queues[component][metric]


def remove_queue(component, metric, args=None):
    """Removes the specified queue from the dict"""
    args = check_comp_args(realtime_queues, component, args)

    if queue_exists(component, metric, args):
        if args:
            realtime_queues[component][args][metric] = None
        else:
            realtime_queues[component][metric] = None


def create_queue_if_not_exists(component, metric, args):
    """ Creates a new Queue if the specified one doesn't already exists """
    if not queue_exists(component, metric, args):
        if args is not None:
            realtime_queues[component][args][metric] = Queue()
        else:
            realtime_queues[component][metric] = Queue()


def queue_exists(component, metric, args):
    """ Checks whether the specified queue already exists """
    if component in realtime_queues:
        if args is not None:
            if args in realtime_queues[component] and metric in realtime_queues[component][args]:
                return True
        elif metric in realtime_queues[component]:
            return True

    return False


def put_measurement_into_queue(component, metric, measurement, args=None):
    """ Puts the given measurement into the specified queue """
    args = check_comp_args(realtime_queues, component, args)

    get_queue(component, metric, args).put(measurement)


def read_measurement_from_queue(component, metric, args=None, blocking=False,
                                timeout=QUEUEMANAGER_DEFAULT_TIMEOUT):
    """ Get a single measurement from the specified queue.
        Warning, could cause Timeout Errors"""
    args = check_comp_args(realtime_queues, component, args)

    if (not get_queue(component, metric, args).empty()) or blocking == True:
        return get_queue(component, metric, args).get(blocking, timeout)
    else:
        return None


def real_time_queue_empty(component, metric, args=None):
    return get_queue(component, metric, args).empty()


def set_gathering_rate(component, metric, delayms, args=None):
    """ Send a gathering rate update that will update the queue and realtime data directory
        in the interval specified with delayms """
    args = check_comp_args(realtime_queues, component, args)

    set_gathering_rate_queue.put({
        "component": component,
        "metric": metric,
        "args": args,
        "delayms": delayms
    })


def request_data(component, metric, args=None):
    """ Request a single data update that gets send into the queue and realtime data dictionary """
    args = check_comp_args(realtime_queues, component, args)

    request_data_queue.put({
        "component": component,
        "metric": metric,
        "args": args
    })