tool: add a script to simulate network bandwith

add a python script to simulate network bandwith using netem tbf to
throttle the connection.
The bandwith used in upload is also monitored. The amount of packets
dropped by netem is also monitored

Change-Id: I895a81f51946914071b7fafa7a102931fa2ec7d6
Tuleap: #1049

tools/test_network.py

@@ -0,0 +1,107 @@
+import subprocess
+import time
+import logging
+import psutil
+import re
+import matplotlib.pyplot as plt
+import argparse
+
+def _remove_rate(interface):
+
+    cmd = ["sudo",
+        "tc", "qdisc", "del", "dev", interface, "root"]
+
+    p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+
+def _change_bitrate(logger, interface, bitrate):
+
+    logger.warning("setting bitrate %s", bitrate)
+    cmd = ["sudo",
+        "tc", "qdisc", "add", "dev", interface, "root", "tbf", "rate",
+        bitrate+"kbit", "latency", "50ms", "burst", bitrate+"b"]
+
+    p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+
+def _init_bitrate_list(first_val, last_val, inc):
+
+    return range(first_val, last_val, inc)
+
+def test_network(logger, interface, time_between_test, path_image):
+
+    logger.warning("running test_case_network_going_down on %s", interface)
+
+    max = 5000
+    min = 2000
+    inc = 200
+
+    list_total_dropped = []
+    list_bits_sent_per_sec = []
+    list_bitrate = _init_bitrate_list(max, min, -inc)
+
+    bits_sent_offset = _add_eth_stats(logger, interface, 0, 0, list_bits_sent_per_sec)
+
+    for bitrate in list_bitrate:
+        _change_bitrate(logger, interface, str(bitrate))
+        time.sleep(time_between_test)
+
+        _add_tc_stats(logger, interface, list_total_dropped)
+        bits_sent_offset = _add_eth_stats(logger, interface, bits_sent_offset, time_between_test, list_bits_sent_per_sec)
+
+        _remove_rate(interface)
+
+    fig, ax = plt.subplots()
+    plt.plot(list_bitrate, ':b', label='bitrate')
+    plt.plot(list_total_dropped, 'r-', label='pkt dropped')
+    plt.plot(list_bits_sent_per_sec, 'g-', label='bits sent')
+    plt.grid(True)
+    legend = plt.legend()
+
+    if path_image:
+        plt.savefig(path_image)
+    else:
+        plt.show()
+
+
+def _add_tc_stats(logger, interface, list_total_dropped):
+
+    cmd = ["tc", "-s", "qdisc", "show", "dev", interface]
+    stdout = subprocess.check_output(cmd)
+    m = re.search('dropped (.+?),', stdout)
+    if m:
+        list_total_dropped.append(int(m.group(1)))
+    else:
+        list_total_dropped.append(0)
+
+def _add_eth_stats(logger, interface, offset, period, list_bits_sent_per_sec):
+
+    ret = psutil.net_io_counters(pernic=True)[interface][0]
+    if period != 0:
+        rate = 8 * (ret - offset) / (period * 1000.0)
+        list_bits_sent_per_sec.append(rate)
+
+    return ret
+
+def init_logger():
+
+    logger = logging.getLogger('test_network')
+    logger.setLevel(logging.WARNING)
+    steam_handler = logging.StreamHandler()
+    steam_handler.setLevel(logging.WARNING)
+    logger.addHandler(steam_handler)
+
+    return logger
+
+def main():
+
+    logger = init_logger()
+    parser = argparse.ArgumentParser()
+    parser.add_argument('-i', '--interface', help='interface', required=True)
+    parser.add_argument('-d', '--delay', help='time between test', required=True)
+    parser.add_argument('-w', '--write', help='path to save images')
+    args = parser.parse_args()
+
+    _remove_rate(args.interface)
+    test_network(logger, args.interface, int(args.delay), args.write)
+
+if __name__ == '__main__':
+    main()