#TopoPerfNext
#
#Topology Performance test for ONOS-next
#
#andrew@onlab.us

import time
import sys
import os
import re

class TopoPerfNext:
    def __init__(self):
        self.default = ''

    def CASE1(self, main):
        '''
        ONOS startup sequence
        '''
        import time
    
        cell_name = main.params['ENV']['cellName']

        git_pull = main.params['GIT']['autoPull']
        checkout_branch = main.params['GIT']['checkout']

        ONOS1_ip = main.params['CTRL']['ip1']
        ONOS2_ip = main.params['CTRL']['ip2']
        ONOS3_ip = main.params['CTRL']['ip3']
        MN1_ip = main.params['MN']['ip1']
        BENCH_ip = main.params['BENCH']['ip']

        main.case("Setting up test environment")

        main.step("Creating cell file")
        cell_file_result = main.ONOSbench.create_cell_file(
                BENCH_ip, cell_name, MN1_ip, "onos-core",
                ONOS1_ip, ONOS2_ip, ONOS3_ip)

        main.step("Applying cell file to environment")
        cell_apply_result = main.ONOSbench.set_cell(cell_name)
        verify_cell_result = main.ONOSbench.verify_cell()
        
        main.step("Git checkout and pull "+checkout_branch)
        if git_pull == 'on':
            checkout_result = \
                    main.ONOSbench.git_checkout(checkout_branch)
            pull_result = main.ONOSbench.git_pull()
        else:
            checkout_result = main.TRUE
            pull_result = main.TRUE
            main.log.info("Skipped git checkout and pull")

        main.step("Using mvn clean & install")
        #mvn_result = main.ONOSbench.clean_install()
        mvn_result = main.TRUE

        main.step("Creating ONOS package")
        package_result = main.ONOSbench.onos_package()

        main.step("Installing ONOS package")
        install1_result = main.ONOSbench.onos_install(node=ONOS1_ip)
        install2_result = main.ONOSbench.onos_install(node=ONOS2_ip)
        install3_result = main.ONOSbench.onos_install(node=ONOS3_ip)

        #NOTE: This step may be unnecessary
        #main.step("Starting ONOS service")
        #start_result = main.ONOSbench.onos_start(ONOS1_ip)

        main.step("Set cell for ONOS cli env")
        main.ONOS1cli.set_cell(cell_name)
        main.ONOS2cli.set_cell(cell_name)
        main.ONOS3cli.set_cell(cell_name)

        time.sleep(10)

        main.step("Start onos cli")
        cli1 = main.ONOS1cli.start_onos_cli(ONOS1_ip)
        cli2 = main.ONOS2cli.start_onos_cli(ONOS2_ip)
        cli3 = main.ONOS3cli.start_onos_cli(ONOS3_ip)

        main.step("Enable metrics feature")
        main.ONOS1cli.feature_install("onos-app-metrics-topology")
        main.ONOS2cli.feature_install("onos-app-metrics-topology")
        main.ONOS3cli.feature_install("onos-app-metrics-topology")

        utilities.assert_equals(expect=main.TRUE,
                actual= cell_file_result and cell_apply_result and\
                        verify_cell_result and checkout_result and\
                        pull_result and mvn_result and\
                        install1_result and install2_result and\
                        install3_result,
                onpass="ONOS started successfully",
                onfail="Failed to start ONOS")

    def CASE2(self, main):
        '''
        Assign s1 to ONOS1 and measure latency
        
        There are 4 levels of latency measurements to this test:
        1) End-to-end measurement: Complete end-to-end measurement
           from TCP (SYN/ACK) handshake to Graph change
        2) OFP-to-graph measurement: 'ONOS processing' snippet of
           measurement from OFP Vendor message to Graph change
        3) OFP-to-device measurement: 'ONOS processing without 
           graph change' snippet of measurement from OFP vendor
           message to Device change timestamp
        4) T0-to-device measurement: Measurement that includes
           the switch handshake to devices timestamp without 
           the graph view change. (TCP handshake -> Device 
           change)
        '''
        import time
        import subprocess
        import json
        import requests
        import os

        ONOS1_ip = main.params['CTRL']['ip1']
        ONOS2_ip = main.params['CTRL']['ip2']
        ONOS3_ip = main.params['CTRL']['ip3']
        ONOS_user = main.params['CTRL']['user']

        default_sw_port = main.params['CTRL']['port1']
       
        #Number of iterations of case
        num_iter = main.params['TEST']['numIter']
       
        #Timestamp 'keys' for json metrics output.
        #These are subject to change, hence moved into params
        deviceTimestamp = main.params['JSON']['deviceTimestamp']
        graphTimestamp = main.params['JSON']['graphTimestamp']

        #List of switch add latency collected from
        #all iterations
        latency_end_to_end_list = []
        latency_ofp_to_graph_list = []
        latency_ofp_to_device_list = []
        latency_t0_to_device_list = []

        #Directory/file to store tshark results
        tshark_of_output = "/tmp/tshark_of_topo.txt"
        tshark_tcp_output = "/tmp/tshark_tcp_topo.txt"

        #String to grep in tshark output
        tshark_tcp_string = "TCP 74 "+default_sw_port
        tshark_of_string = "OFP 86 Vendor"
     
        #Initialize assertion to TRUE
        assertion = main.TRUE
        
        main.log.report("Latency of adding one switch")

        for i in range(0, int(num_iter)):
            main.log.info("Starting tshark capture")

            #* TCP [ACK, SYN] is used as t0_a, the
            #  very first "exchange" between ONOS and 
            #  the switch for end-to-end measurement
            #* OFP [Stats Reply] is used for t0_b
            #  the very last OFP message between ONOS
            #  and the switch for ONOS measurement
            main.ONOS1.tshark_grep(tshark_tcp_string,
                    tshark_tcp_output)
            main.ONOS1.tshark_grep(tshark_of_string,
                    tshark_of_output)

            #Wait and ensure tshark is started and 
            #capturing
            time.sleep(10)

            main.log.info("Assigning s1 to controller")

            main.Mininet1.assign_sw_controller(sw="1",
                    ip1=ONOS1_ip, port1=default_sw_port)

            #Wait and ensure switch is assigned
            #before stopping tshark
            time.sleep(30)
   
            main.log.info("Stopping all Tshark processes")
            main.ONOS1.stop_tshark()

            #tshark output is saved in ONOS. Use subprocess
            #to copy over files to TestON for parsing
            main.log.info("Copying over tshark files")
            
            #TCP CAPTURE ****
            #Copy the tshark output from ONOS machine to
            #TestON machine in tshark_tcp_output directory>file
            os.system("scp "+ONOS_user+"@"+ONOS1_ip+":"+
                    tshark_tcp_output+" /tmp/") 
            tcp_file = open(tshark_tcp_output, 'r')
            temp_text = tcp_file.readline()
            temp_text = temp_text.split(" ")

            main.log.info("Object read in from TCP capture: "+
                    str(temp_text))
            if len(temp_text) > 1:
                t0_tcp = float(temp_text[1])*1000.0
            else:
                main.log.error("Tshark output file for TCP"+
                        " returned unexpected results")
                t0_tcp = 0
                assertion = main.FALSE
            
            tcp_file.close()
            #****************

            #OF CAPTURE ****
            os.system("scp "+ONOS_user+"@"+ONOS1_ip+":"+
                    tshark_of_output+" /tmp/")
            of_file = open(tshark_of_output, 'r')
           
            line_ofp = ""
            #Read until last line of file
            while True:
                temp_text = of_file.readline()
                if temp_text !='':
                    line_ofp = temp_text
                else:
                    break 
            obj = line_ofp.split(" ")
            
            main.log.info("Object read in from OFP capture: "+
                    str(line_ofp))
    
            if len(line_ofp) > 1:
                t0_ofp = float(obj[1])*1000.0
            else:
                main.log.error("Tshark output file for OFP"+
                        " returned unexpected results")
                t0_ofp = 0
                assertion = main.FALSE
            
            of_file.close()
            #****************
           
            json_str_1 = main.ONOS1cli.topology_events_metrics()
            json_str_2 = main.ONOS2cli.topology_events_metrics()
            json_str_3 = main.ONOS3cli.topology_events_metrics()

            json_obj_1 = json.loads(json_str_1)
            json_obj_2 = json.loads(json_str_2)
            json_obj_3 = json.loads(json_str_3)

            #Obtain graph timestamp. This timestsamp captures
            #the epoch time at which the topology graph was updated.
            graph_timestamp_1 = \
                    json_obj_1[graphTimestamp]['value']
            graph_timestamp_2 = \
                    json_obj_2[graphTimestamp]['value']
            graph_timestamp_3 = \
                    json_obj_3[graphTimestamp]['value']

            #Obtain device timestamp. This timestamp captures
            #the epoch time at which the device event happened
            device_timestamp_1 = \
                    json_obj_1[deviceTimestamp]['value'] 
            device_timestamp_2 = \
                    json_obj_2[deviceTimestamp]['value'] 
            device_timestamp_3 = \
                    json_obj_3[deviceTimestamp]['value'] 

            #t0 to device processing latency 
            delta_device_1 = int(device_timestamp_1) - int(t0_tcp)
            delta_device_2 = int(device_timestamp_2) - int(t0_tcp)
            delta_device_3 = int(device_timestamp_3) - int(t0_tcp)
        
            #Get average of delta from all instances
            avg_delta_device = \
                    (int(delta_device_1)+\
                     int(delta_device_2)+\
                     int(delta_device_3)) / 3

            #Ensure avg delta meets the threshold before appending
            if avg_delta_device > 0.0 and avg_delta_device < 10000:
                latency_t0_to_device_list.append(avg_delta_device)
            else:
                main.log.info("Results for t0-to-device ignored"+\
                        "due to excess in threshold")

            #t0 to graph processing latency (end-to-end)
            delta_graph_1 = int(graph_timestamp_1) - int(t0_tcp)
            delta_graph_2 = int(graph_timestamp_2) - int(t0_tcp)
            delta_graph_3 = int(graph_timestamp_3) - int(t0_tcp)
        
            #Get average of delta from all instances
            avg_delta_graph = \
                    (int(delta_graph_1)+\
                     int(delta_graph_2)+\
                     int(delta_graph_3)) / 3

            #Ensure avg delta meets the threshold before appending
            if avg_delta_graph > 0.0 and avg_delta_graph < 10000:
                latency_end_to_end_list.append(avg_delta_graph)
            else:
                main.log.info("Results for end-to-end ignored"+\
                        "due to excess in threshold")

            #ofp to graph processing latency (ONOS processing)
            delta_ofp_graph_1 = int(graph_timestamp_1) - int(t0_ofp)
            delta_ofp_graph_2 = int(graph_timestamp_2) - int(t0_ofp)
            delta_ofp_graph_3 = int(graph_timestamp_3) - int(t0_ofp)
            
            avg_delta_ofp_graph = \
                    (int(delta_ofp_graph_1)+\
                     int(delta_ofp_graph_2)+\
                     int(delta_ofp_graph_3)) / 3
            
            if avg_delta_ofp_graph > 0.0 and avg_delta_ofp_graph < 10000:
                latency_ofp_to_graph_list.append(avg_delta_ofp_graph)
            else:
                main.log.info("Results for ofp-to-graph "+\
                        "ignored due to excess in threshold")

            #ofp to device processing latency (ONOS processing)
            delta_ofp_device_1 = float(device_timestamp_1) - float(t0_ofp)
            delta_ofp_device_2 = float(device_timestamp_2) - float(t0_ofp)
            delta_ofp_device_3 = float(device_timestamp_3) - float(t0_ofp)
            
            avg_delta_ofp_device = \
                    (float(delta_ofp_device_1)+\
                     float(delta_ofp_device_2)+\
                     float(delta_ofp_device_3)) / 3.0
            
            #NOTE: ofp - delta measurements are occasionally negative
            #      due to system time misalignment.
            #TODO: Implement ptp across all clusters
            #Just add the calculation to list for now
            latency_ofp_to_device_list.append(avg_delta_ofp_device)

            #TODO:
            #Fetch logs upon threshold excess

            
            main.log.info("ONOS1 delta end-to-end: "+
                    str(delta_graph_1) + " ms")
            main.log.info("ONOS2 delta end-to-end: "+
                    str(delta_graph_2) + " ms")
            main.log.info("ONOS3 delta end-to-end: "+
                    str(delta_graph_3) + " ms")

            main.log.info("ONOS1 delta OFP - graph: "+
                    str(delta_ofp_graph_1) + " ms")
            main.log.info("ONOS2 delta OFP - graph: "+
                    str(delta_ofp_graph_2) + " ms")
            main.log.info("ONOS3 delta OFP - graph: "+
                    str(delta_ofp_graph_3) + " ms")
            
            main.log.info("ONOS1 delta device - t0: "+
                    str(delta_device_1) + " ms")
            main.log.info("ONOS2 delta device - t0: "+
                    str(delta_device_2) + " ms")
            main.log.info("ONOS3 delta device - t0: "+
                    str(delta_device_3) + " ms")
          
            main.log.info("ONOS1 delta OFP - device: "+
                    str(delta_ofp_device_1) + " ms")
            main.log.info("ONOS2 delta OFP - device: "+
                    str(delta_ofp_device_2) + " ms")
            main.log.info("ONOS3 delta OFP - device: "+
                    str(delta_ofp_device_3) + " ms")

            main.step("Remove switch from controller")
            main.Mininet1.delete_sw_controller("s1")

            time.sleep(5)

        #END of for loop iteration

        #If there is at least 1 element in each list,
        #pass the test case
        if len(latency_end_to_end_list) > 0 and\
           len(latency_ofp_to_graph_list) > 0 and\
           len(latency_ofp_to_device_list) > 0 and\
           len(latency_t0_to_device_list) > 0:
            assertion = main.TRUE
        elif len(latency_end_to_end_list) == 0:
            #The appending of 0 here is to prevent 
            #the min,max,sum functions from failing 
            #below
            latency_end_to_end_list.append(0)
            assertion = main.FALSE
        elif len(latency_ofp_to_graph_list) == 0:
            latency_ofp_to_graph_list.append(0)
            assertion = main.FALSE
        elif len(latency_ofp_to_device_list) == 0:
            latency_ofp_to_device_list.append(0)
            assertion = main.FALSE
        elif len(latency_t0_to_device_list) == 0:
            latency_t0_to_device_list.append(0)
            assertion = main.FALSE

        #Calculate min, max, avg of latency lists
        latency_end_to_end_max = \
                int(max(latency_end_to_end_list))
        latency_end_to_end_min = \
                int(min(latency_end_to_end_list))
        latency_end_to_end_avg = \
                (int(sum(latency_end_to_end_list)) / \
                 len(latency_end_to_end_list))
   
        latency_ofp_to_graph_max = \
                int(max(latency_ofp_to_graph_list))
        latency_ofp_to_graph_min = \
                int(min(latency_ofp_to_graph_list))
        latency_ofp_to_graph_avg = \
                (int(sum(latency_ofp_to_graph_list)) / \
                 len(latency_ofp_to_graph_list))

        latency_ofp_to_device_max = \
                int(max(latency_ofp_to_device_list))
        latency_ofp_to_device_min = \
                int(min(latency_ofp_to_device_list))
        latency_ofp_to_device_avg = \
                (int(sum(latency_ofp_to_device_list)) / \
                 len(latency_ofp_to_device_list))

        latency_t0_to_device_max = \
                float(max(latency_t0_to_device_list))
        latency_t0_to_device_min = \
                float(min(latency_t0_to_device_list))
        latency_t0_to_device_avg = \
                (float(sum(latency_t0_to_device_list)) / \
                 len(latency_ofp_to_device_list))

        main.log.report("Switch add - End-to-end latency: \n"+\
                "Min: "+str(latency_end_to_end_min)+"\n"+\
                "Max: "+str(latency_end_to_end_max)+"\n"+\
                "Avg: "+str(latency_end_to_end_avg))
        main.log.report("Switch add - OFP-to-Graph latency: \n"+\
                "Min: "+str(latency_ofp_to_graph_min)+"\n"+\
                "Max: "+str(latency_ofp_to_graph_max)+"\n"+\
                "Avg: "+str(latency_ofp_to_graph_avg))
        main.log.report("Switch add - OFP-to-Device latency: \n"+\
                "Min: "+str(latency_ofp_to_device_min)+"\n"+\
                "Max: "+str(latency_ofp_to_device_max)+"\n"+\
                "Avg: "+str(latency_ofp_to_device_avg))
        main.log.report("Switch add - t0-to-Device latency: \n"+\
                "Min: "+str(latency_t0_to_device_min)+"\n"+\
                "Max: "+str(latency_t0_to_device_max)+"\n"+\
                "Avg: "+str(latency_t0_to_device_avg))

        utilities.assert_equals(expect=main.TRUE, actual=assertion,
                onpass="Switch latency test successful",
                onfail="Switch latency test failed")

    def CASE3(self, main):
        '''
        Bring port up / down and measure latency.
        Port enable / disable is simulated by ifconfig up / down
        
        In ONOS-next, we must ensure that the port we are 
        manipulating is connected to another switch with a valid
        connection. Otherwise, graph view will not be updated.
        '''
        import time
        import subprocess
        import os
        import requests
        import json

        ONOS1_ip = main.params['CTRL']['ip1']
        ONOS2_ip = main.params['CTRL']['ip2']
        ONOS3_ip = main.params['CTRL']['ip3']
        ONOS_user = main.params['CTRL']['user']

        default_sw_port = main.params['CTRL']['port1']
       
        #Number of iterations of case
        num_iter = main.params['TEST']['numIter']
       
        #Timestamp 'keys' for json metrics output.
        #These are subject to change, hence moved into params
        deviceTimestamp = main.params['JSON']['deviceTimestamp']
        graphTimestamp = main.params['JSON']['graphTimestamp']

        #NOTE: Some hardcoded variables you may need to configure
        #      besides the params
            
        tshark_port_status = "OFP 130 Port Status"

        tshark_port_up = "/tmp/tshark_port_up.txt"
        tshark_port_down = "/tmp/tshark_port_down.txt"
        interface_config = "s1-eth1"

        main.log.report("Port enable / disable latency")

        main.step("Assign switches s1 and s2 to controller 1")
        main.Mininet1.assign_sw_controller(sw="1",ip1=ONOS1_ip,
                port1=default_sw_port)
        main.Mininet1.assign_sw_controller(sw="2",ip1=ONOS1_ip,
                port1=default_sw_port)

        main.step("Verify switch is assigned correctly")
        result_s1 = main.Mininet1.get_sw_controller(sw="s1")
        result_s2 = main.Mininet1.get_sw_controller(sw="s2")
        if result_s1 == main.FALSE or result_s2 == main.FALSE:
            main.log.info("Switch s1 was not assigned correctly")
            assertion = main.FALSE
        else:
            main.log.info("Switch s1 was assigned correctly")

        port_up_device_to_ofp_list = []
        port_up_graph_to_ofp_list = []
        port_down_device_to_ofp_list = []
        port_down_graph_to_ofp_list = []

        for i in range(0, int(num_iter)):
            main.step("Starting wireshark capture for port status down")
            main.ONOS1.tshark_grep(tshark_port_status,
                    tshark_port_down)
            
            time.sleep(10)

            #Disable interface that is connected to switch 2
            main.step("Disable port: "+interface_config)
            main.Mininet2.handle.sendline("sudo ifconfig "+
                    interface_config+" down")
            main.Mininet2.handle.expect("\$")
            time.sleep(20)

            main.ONOS1.tshark_stop()
            time.sleep(5)
            
            #Copy tshark output file from ONOS to TestON instance
            #/tmp directory
            os.system("scp "+ONOS_user+"@"+ONOS1_ip+":"+
                    tshark_port_down+" /tmp/")

            f_port_down = open(tshark_port_down, 'r')
            #Get first line of port down event from tshark
            f_line = f_port_down.readline()
            obj_down = f_line.split(" ")
            if len(f_line) > 0:
                timestamp_begin_pt_down = int(float(obj_down[1]))*1000
                main.log.info("Port down begin timestamp: "+
                        str(timestamp_begin_pt_down))
            else:
                main.log.info("Tshark output file returned unexpected"+
                        " results: "+str(obj_down))
                timestamp_begin_pt_down = 0
            
            f_port_down.close()

            main.step("Obtain t1 by REST call")
            json_str_1 = main.ONOS1cli.topology_events_metrics()
            json_str_2 = main.ONOS2cli.topology_events_metrics()
            json_str_3 = main.ONOS3cli.topology_events_metrics()

            json_obj_1 = json.loads(json_str_1)
            json_obj_2 = json.loads(json_str_2)
            json_obj_3 = json.loads(json_str_3)
           
            time.sleep(5)

            #Obtain graph timestamp. This timestsamp captures
            #the epoch time at which the topology graph was updated.
            graph_timestamp_1 = \
                    json_obj_1[graphTimestamp]['value']
            graph_timestamp_2 = \
                    json_obj_2[graphTimestamp]['value']
            graph_timestamp_3 = \
                    json_obj_3[graphTimestamp]['value']

            #TODO: Test purposes, remove later
            main.log.info("json_timestamp graph: "+str(graph_timestamp_1))
            main.log.info("json_timestamp graph: "+str(graph_timestamp_2))
            main.log.info("json_timestamp graph: "+str(graph_timestamp_3))

            #Obtain device timestamp. This timestamp captures
            #the epoch time at which the device event happened
            device_timestamp_1 = \
                    json_obj_1[deviceTimestamp]['value'] 
            device_timestamp_2 = \
                    json_obj_2[deviceTimestamp]['value'] 
            device_timestamp_3 = \
                    json_obj_3[deviceTimestamp]['value'] 
            
            #TODO: Test purposes, remove later
            main.log.info("json_timestamp device: "+str(device_timestamp_1))
            main.log.info("json_timestamp device: "+str(device_timestamp_2))
            main.log.info("json_timestamp device: "+str(device_timestamp_3))

            #Get delta between graph event and OFP 
            pt_down_graph_to_ofp_1 = int(graph_timestamp_1) -\
                    int(timestamp_begin_pt_down)
            pt_down_graph_to_ofp_2 = int(graph_timestamp_2) -\
                    int(timestamp_begin_pt_down)
            pt_down_graph_to_ofp_3 = int(graph_timestamp_3) -\
                    int(timestamp_begin_pt_down)

            #Get delta between device event and OFP
            pt_down_device_to_ofp_1 = int(device_timestamp_1) -\
                    int(timestamp_begin_pt_down)
            pt_down_device_to_ofp_2 = int(device_timestamp_2) -\
                    int(timestamp_begin_pt_down)
            pt_down_device_to_ofp_3 = int(device_timestamp_3) -\
                    int(timestamp_begin_pt_down)
       
            #Caluclate average across clusters
            pt_down_graph_to_ofp_avg =\
                    (int(pt_down_graph_to_ofp_1) +
                     int(pt_down_graph_to_ofp_2) + 
                     int(pt_down_graph_to_ofp_3)) / 3
            pt_down_device_to_ofp_avg = \
                    (int(pt_down_device_to_ofp_1) + 
                     int(pt_down_device_to_ofp_2) +
                     int(pt_down_device_to_ofp_3)) / 3

            if pt_down_graph_to_ofp_avg > 0 and \
                    pt_down_graph_to_ofp_avg < 1000:
                port_down_graph_to_ofp_list.append(
                        pt_down_graph_to_ofp_avg)
            else:
                main.log.info("Average port down graph-to-ofp result" +
                        " exceeded the threshold: "+
                        str(pt_down_graph_to_ofp_avg))

            if pt_down_device_to_ofp_avg > 0 and \
                    pt_down_device_to_ofp_avg < 1000:
                port_down_device_to_ofp_list.append(
                        pt_down_device_to_ofp_avg)
            else:
                main.log.info("Average port down device-to-ofp result" +
                        " exceeded the threshold: "+
                        str(pt_down_device_to_ofp_avg))

            #TODO: Remove these logs. For test purposes only
            main.log.info("Delta1 down graph: "+str(pt_down_graph_to_ofp_1))
            main.log.info("Delta2 down graph: "+str(pt_down_graph_to_ofp_2))
            main.log.info("Delta3 down graph: "+str(pt_down_graph_to_ofp_3))
            
            main.log.info("Delta1 down device: "+
                    str(pt_down_device_to_ofp_1))
            main.log.info("Delta2 down device: "+
                    str(pt_down_device_to_ofp_2))
            main.log.info("Delta3 down device: "+
                    str(pt_down_device_to_ofp_3))
        
            #Port up events 
            main.step("Enable port and obtain timestamp")
            main.step("Starting wireshark capture for port status up")
            main.ONOS1.tshark_grep("OFP 130 Port Status", tshark_port_up)
            time.sleep(10)

            main.Mininet2.handle.sendline("sudo ifconfig "+
                    interface_config+" up")
            main.Mininet2.handle.expect("\$")
            time.sleep(20)

            os.system("scp "+ONOS_user+"@"+ONOS1_ip+":"+
                    tshark_port_up+" /tmp/")

            f_port_up = open(tshark_port_up, 'r')
            f_line = f_port_up.readline()
            obj_up = f_line.split(" ")
            if len(f_line) > 0:
                timestamp_begin_pt_up = int(float(obj_up[1]))*1000
                main.log.info("Port up begin timestamp: "+
                        str(timestamp_begin_pt_up))
            else:
                main.log.info("Tshark output file returned unexpected"+
                        " results.")
                timestamp_begin_pt_up = 0
            
            f_port_up.close()

            main.step("Obtain t1 by REST call")
            #TODO: Implement json object parsing here
            json_str_1 = main.ONOS1cli.topology_events_metrics()
            json_str_2 = main.ONOS2cli.topology_events_metrics()
            json_str_3 = main.ONOS3cli.topology_events_metrics()

            json_obj_1 = json.loads(json_str_1)
            json_obj_2 = json.loads(json_str_2)
            json_obj_3 = json.loads(json_str_3)

            #Obtain graph timestamp. This timestsamp captures
            #the epoch time at which the topology graph was updated.
            graph_timestamp_1 = \
                    json_obj_1[graphTimestamp]['value']
            graph_timestamp_2 = \
                    json_obj_2[graphTimestamp]['value']
            graph_timestamp_3 = \
                    json_obj_3[graphTimestamp]['value']

            #Obtain device timestamp. This timestamp captures
            #the epoch time at which the device event happened
            device_timestamp_1 = \
                    json_obj_1[deviceTimestamp]['value'] 
            device_timestamp_2 = \
                    json_obj_2[deviceTimestamp]['value'] 
            device_timestamp_3 = \
                    json_obj_3[deviceTimestamp]['value'] 

            #Get delta between graph event and OFP 
            pt_up_graph_to_ofp_1 = int(graph_timestamp_1) -\
                    int(timestamp_begin_pt_up)
            pt_up_graph_to_ofp_2 = int(graph_timestamp_2) -\
                    int(timestamp_begin_pt_up)
            pt_up_graph_to_ofp_3 = int(graph_timestamp_3) -\
                    int(timestamp_begin_pt_up)

            #Get delta between device event and OFP
            pt_up_device_to_ofp_1 = int(device_timestamp_1) -\
                    int(timestamp_begin_pt_up)
            pt_up_device_to_ofp_2 = int(device_timestamp_2) -\
                    int(timestamp_begin_pt_up)
            pt_up_device_to_ofp_3 = int(device_timestamp_3) -\
                    int(timestamp_begin_pt_up)

            pt_up_graph_to_ofp_avg = \
                    (float(pt_up_graph_to_ofp_1) + 
                     float(pt_up_graph_to_ofp_2) +
                     float(pt_up_graph_to_ofp_3)) / 3

            pt_up_device_to_ofp_avg = \
                    (float(pt_up_device_to_ofp_1) + 
                     float(pt_up_device_to_ofp_2) +
                     float(pt_up_device_to_ofp_3)) / 3

            if pt_up_graph_to_ofp_avg > 0 and \
                    pt_up_graph_to_ofp_avg < 1000:
                port_up_graph_to_ofp_list.append(
                        pt_up_graph_to_ofp_avg)
            else:
                main.log.info("Average port up graph-to-ofp result"+
                        " exceeded the threshold: "+
                        str(pt_up_graph_to_ofp_avg))
            
            if pt_up_device_to_ofp_avg > 0 and \
                    pt_up_device_to_ofp_avg < 1000:
                port_up_device_to_ofp_list.append(
                        pt_up_device_to_ofp_avg)
            else:
                main.log.info("Average port up graph-to-ofp result"+
                        " exceeded the threshold: "+
                        str(pt_up_device_to_ofp_avg))

            #TODO: Remove these logs. For test purposes only
            main.log.info("Delta1 up graph: "+str(pt_up_graph_to_ofp_1))
            main.log.info("Delta2 up graph: "+str(pt_up_graph_to_ofp_2))
            main.log.info("Delta3 up graph: "+str(pt_up_graph_to_ofp_3))
             
            main.log.info("Delta1 down device: "+
                    str(pt_up_device_to_ofp_1))
            main.log.info("Delta2 down device: "+
                    str(pt_up_device_to_ofp_2))
            main.log.info("Delta3 down device: "+
                    str(pt_up_device_to_ofp_3))
            
            #END ITERATION FOR LOOP
        
        port_down_graph_to_ofp_min = min(port_down_graph_to_ofp_list)
        port_down_graph_to_ofp_max = max(port_down_graph_to_ofp_list)
        port_down_graph_to_ofp_avg = \
                (sum(port_down_graph_to_ofp_list) / 
                 len(port_down_graph_to_ofp_list))
        
        main.log.report("Port up graph-to-ofp Min: ")
        main.log.report("Port up graph-to-ofp Max: ")
        main.log.report("Port up graph-to-ofp Avg: ")
            
    def CASE4(self, main):
        '''
        Link down event using loss rate 100%
        '''
        import time
        import subprocess
        import os
        import requests
        import json

        ONOS1_ip = main.params['CTRL']['ip1']
        ONOS2_ip = main.params['CTRL']['ip2']
        ONOS3_ip = main.params['CTRL']['ip3']
        ONOS_user = main.params['CTRL']['user']

        default_sw_port = main.params['CTRL']['port1']
       
        #Number of iterations of case
        num_iter = main.params['TEST']['numIter']
       
        #Timestamp 'keys' for json metrics output.
        #These are subject to change, hence moved into params
        deviceTimestamp = main.params['JSON']['deviceTimestamp']
        linkTimestamp = main.params['JSON']['linkTimestamp'] 
           
        assertion = main.TRUE
        #Link event timestamp to system time list
        link_down_link_to_system_list = []
        link_up_link_to_system_list = []
        #Graph event timestamp to system time list
        link_down_graph_to_system_list = []
        link_up_graph_to_system_list = [] 

        main.log.report("Add / remove link latency between "+
                "two switches")

        main.step("Assign all switches")
        main.Mininet1.assign_sw_controller(sw="1",
                ip1=ONOS1_ip, port1=default_sw_port)
        main.Mininet1.assign_sw_controller(sw="2",
                ip1=ONOS1_ip, port1=default_sw_port)

        main.step("Verifying switch assignment")
        result_s1 = main.Mininet1.get_sw_controller(sw="s1")
        result_s2 = main.Mininet1.get_sw_controller(sw="s2")

        if result_s1 == main.TRUE and result_s2 == main.TRUE:
            main.log.report("Switches s1, s2 assigned successfully")
        else:
            main.log.error("Error assigning switches s1 and s2")
            assertion = main.FALSE
          
        #Allow time for events to finish before taking measurements
        time.sleep(10)

        #Start iteration of link event test
        for i in range(0, int(num_iter)):
            main.step("Getting initial system time as t0")
            
            timestamp_link_down_t0 = time.time() * 1000
            #Link down is simulated by 100% loss rate using traffic 
            #control command
            main.Mininet1.handle.sendline(
                    "sh tc qdisc add dev s1-eth1 root netem loss 100%")

            #TODO: Iterate through topology count to detect 
            #      link down discovery. Take timestamp and
            #      gather list for num_iter