views.py

#!/usr/bin/python3
"""
// © University of Southampton IT Innovation Centre, 2018
//
// Copyright in this software belongs to University of Southampton
// IT Innovation Centre of Gamma House, Enterprise Road,
// Chilworth Science Park, Southampton, SO16 7NS, UK.
//
// This software may not be used, sold, licensed, transferred, copied
// or reproduced in whole or in part in any manner or form or in or
// on any media by any person other than in accordance with the terms
// of the Licence Agreement supplied with the software, or otherwise
// without the prior written consent of the copyright owners.
//
// This software is distributed WITHOUT ANY WARRANTY, without even the
// implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
// PURPOSE, except where stated in the Licence Agreement supplied with
// the software.
//
//      Created By :            Nikolay Stanchev
//      Created Date :          04-07-2018
//      Created for Project :   FLAME
"""


from clmcservice.graphapi.utilities import validate_json_queries_body, validate_graph_url_params, build_temporal_graph, delete_temporal_subgraph, validate_graph_rtt_params, RTT_CYPHER_QUERY_TEMPLATE
from uuid import uuid4
from influxdb import InfluxDBClient
from py2neo import Graph
from pyramid.httpexceptions import HTTPBadRequest, HTTPNotFound
from pyramid.view import view_defaults, view_config
import logging


log = logging.getLogger('service_logger')


@view_defaults(renderer='json')
class GraphAPI(object):
    """
    A class-based view for  building temporal graphs and running graph queries.
    """

    def __init__(self, request):
        """
        Initialises the instance of the view with the request argument.

        :param request: client's call request
        """

        self.request = request

    @view_config(route_name='graph_build', request_method='POST')
    def build_temporal_graph(self):
        """
        An API endpoint to build a temporal graph and store it in neo4j based on the posted JSON query document.
        The request parameters must also include URL query parameters defining the time range for which the graph must be generated.

        :raises HTTPBadRequest: if request body is not a valid JSON with the queries per service function or if request URL doesn't contain the required URL query parameters
        :return: A JSON document containing the posted request body, along with meta data about the built graph (time range and uuid, which can then be reused for other API calls)
        """

        try:
            body = self.request.body.decode(self.request.charset)
            json_queries = validate_json_queries_body(body)  # validate the content and receive a json dictionary object
        except AssertionError as e:
            raise HTTPBadRequest("Bad request content: {0}".format(e.args))

        try:
            params = validate_graph_url_params(self.request.params)
        except AssertionError as e:
            raise HTTPBadRequest("Request URL format is incorrect: {0}".format(e.args))

        graph = Graph(host=self.request.registry.settings['neo4j_host'], password=self.request.registry.settings['neo4j_password'])
        influx_client = InfluxDBClient(host=self.request.registry.settings['influx_host'], port=self.request.registry.settings['influx_port'], timeout=10)

        database_name = json_queries["service_function_chain"]
        if database_name not in [db["name"] for db in influx_client.get_list_database()]:
            raise HTTPBadRequest("Database for service function chain {0} not found.".format(database_name))

        from_timestamp = params['from'] * 10**9
        to_timestamp = params['to'] * 10**9

        request_id = str(uuid4())

        build_temporal_graph(request_id, from_timestamp, to_timestamp, json_queries, graph, influx_client)
        json_queries['graph'] = {"uuid": request_id, "time_range": {"from": from_timestamp, "to": to_timestamp}}
        return json_queries

    @view_config(route_name='graph_manage', request_method='DELETE')
    def delete_temporal_graph(self):
        """
        An API endpoint to delete a temporal graph associated with a uuid generated by the CLMC service.

        :return: A JSON document containing the UUID of the deleted subgraph
        :raises HTTPNotFound: if the request is not associated with any subgraph
        """

        graph_id = self.request.matchdict['graph_id']  # get the UUID of the subgraph from the URL
        graph = Graph(host=self.request.registry.settings['neo4j_host'], password=self.request.registry.settings['neo4j_password'])  # connect to the neo4j graph db

        if graph.nodes.match("Reference", uuid=graph_id).first() is None:
            raise HTTPNotFound("No subgraph found associated with the request ID {0}".format(graph_id))

        number_of_deleted_nodes = delete_temporal_subgraph(graph, graph_id)
        return {"uuid": graph_id, "deleted": number_of_deleted_nodes}

    @view_config(route_name='graph_algorithms_rtt', request_method='GET')
    def run_rtt_query(self):
        """
        An API endpoint to run the round trip time cypher query over the graph associated with a given request ID.

        :return: A JSON response with a list of forward latencies, reverse latencies and SF endpoint response time.
        :raises HTTPBadRequest: if the request URL doesn't contain the required URL query parameters
        :raises HTTPNotFound: if the request is not associated with any subgraph or the compute node / endpoint node doesn't exist
        """

        graph_id = self.request.matchdict['graph_id']  # get the UUID of the subgraph from the URL

        try:
            params = validate_graph_rtt_params(self.request.params)
        except AssertionError as e:
            raise HTTPBadRequest("Request URL format is incorrect: {0}".format(e.args))

        compute_node_label = params["compute_node"]
        endpoint_node_label = params["endpoint"]

        graph = Graph(host=self.request.registry.settings['neo4j_host'], password=self.request.registry.settings['neo4j_password'])  # connect to the neo4j graph db

        all_nodes = graph.nodes

        reference_node = all_nodes.match("Reference", uuid=graph_id).first()
        if reference_node is None:
            raise HTTPNotFound("No subgraph found associated with the request ID {0}".format(graph_id))

        compute_node = all_nodes.match("ComputeNode", name=compute_node_label).first()
        if compute_node is None:
            raise HTTPNotFound("Compute node {0} doesn't exist.".format(compute_node_label))

        endpoint_node = all_nodes.match("Endpoint", name=endpoint_node_label, uuid=graph_id).first()
        if endpoint_node is None:
            raise HTTPNotFound("Endpoint node {0} doesn't exist.".format(endpoint_node_label))

        # check if the endpoint is hosted by the compute node before running the RTT cypher query
        hosted_by_node = graph.relationships.match(nodes=(endpoint_node, None), r_type="hostedBy").first().end_node
        if hosted_by_node["name"] == compute_node["name"]:
            result = {"forward_latencies": [], "reverse_latencies": [], "response_time": endpoint_node["response_time"],
                      "request_size": endpoint_node["request_size"], "response_size": endpoint_node["response_size"]}
        else:
            query_to_execute = RTT_CYPHER_QUERY_TEMPLATE.format(compute_node_label, endpoint_node_label, graph_id)
            log.info("Executing cypher query: {0}".format(query_to_execute))
            data = graph.run(query_to_execute).data()  # returns a list of dictionaries, each dictionary represents a row in the result
            result = data[0]

        sf_node = graph.match(nodes=(None, endpoint_node), r_type="realisedBy").first().start_node
        if sf_node is None:
            msg = "No service function found associated with endpoint {0}".format(endpoint_node["name"])
            log.error("Unexpected error: {0}".format(msg))
            raise HTTPBadRequest(msg)

        sf_package_node = graph.match(nodes=(sf_node, None), r_type="instanceOf").first().end_node
        if sf_package_node is None:
            msg = "No service function package found associated with service function {0}".format(sf_node["name"])
            log.error("Unexpected error: {0}".format(msg))
            raise HTTPBadRequest(msg)

        result["global_tags"] = {"sfe": endpoint_node["name"], "server": hosted_by_node["name"], "location": hosted_by_node["name"],
                                 "sfc": reference_node["sfc"], "sfci": reference_node["sfci"], "sfp": sf_package_node["name"], "sf": sf_node["name"]}

        # calculate the Round-Trip-Time
        total_forward_latency = sum(result["forward_latencies"])
        result["total_forward_latency"] = total_forward_latency
        total_reverse_latency = sum(result["reverse_latencies"])
        result["total_reverse_latency"] = total_reverse_latency
        bandwidth = self.request.registry.settings["network_bandwidth"]
        result["bandwidth"] = bandwidth
        service_delay = result["response_time"]
        request_size = result["request_size"]
        response_size = result["response_size"]

        round_trip_time = self.calculate_round_trip_time(total_forward_latency, total_reverse_latency, service_delay, request_size, response_size, bandwidth)
        result["round_trip_time"] = round_trip_time

        return result

    @staticmethod
    def calculate_round_trip_time(forward_latency, reverse_latency, service_delay, request_size, response_size, bandwidth, packet_size=1500, packet_header_size=50):
        """
        Calculates the round trip time given the list of arguments.

        :param forward_latency: network latency in forward direction (s)
        :param reverse_latency: network latency in reverse direction (s)
        :param service_delay: media service delay (s)
        :param request_size: request size (bytes)
        :param response_size: response size (bytes)
        :param bandwidth: network bandwidth (Mb/s)
        :param packet_size: size of packet (bytes)
        :param packet_header_size: size of the header of the packet (bytes)
        :return: the calculated round trip time
        """

        if forward_latency > 0 and reverse_latency > 0:
            forward_data_delay = (8/10**6) * (request_size / bandwidth) * (packet_size / (packet_size - packet_header_size))
            reverse_data_delay = (8/10**6) * (response_size / bandwidth) * (packet_size / (packet_size - packet_header_size))
        else:
            forward_data_delay, reverse_data_delay = 0, 0

        return forward_latency + forward_data_delay + service_delay + reverse_latency + reverse_data_delay