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"""Entry point for running stress tests."""

import argparse
import Queue
import threading

from grpc.beta import implementations
from src.proto.grpc.testing import metrics_pb2
from src.proto.grpc.testing import test_pb2

from tests.interop import methods
from tests.qps import histogram
from tests.stress import metrics_server
from tests.stress import test_runner


def _args():
  parser = argparse.ArgumentParser(description='gRPC Python stress test client')
  parser.add_argument(
      '--server_addresses',
      help='comma seperated list of hostname:port to run servers on',
      default='localhost:8080', type=str)
  parser.add_argument(
      '--test_cases',
      help='comma seperated list of testcase:weighting of tests to run',
      default='large_unary:100',
      type=str)
  parser.add_argument(
      '--test_duration_secs',
      help='number of seconds to run the stress test',
      default=-1, type=int)
  parser.add_argument(
      '--num_channels_per_server',
      help='number of channels per server',
      default=1, type=int)
  parser.add_argument(
      '--num_stubs_per_channel',
      help='number of stubs to create per channel',
      default=1, type=int)
  parser.add_argument(
      '--metrics_port',
      help='the port to listen for metrics requests on',
      default=8081, type=int)
  return parser.parse_args()


def _test_case_from_arg(test_case_arg):
  for test_case in methods.TestCase:
    if test_case_arg == test_case.value:
      return test_case
  else:
    raise ValueError('No test case {}!'.format(test_case_arg))


def _parse_weighted_test_cases(test_case_args):
  weighted_test_cases = {}
  for test_case_arg in test_case_args.split(','):
    name, weight = test_case_arg.split(':', 1)
    test_case = _test_case_from_arg(name)
    weighted_test_cases[test_case] = int(weight)
  return weighted_test_cases


def run_test(args):
  test_cases = _parse_weighted_test_cases(args.test_cases)
  test_servers = args.server_addresses.split(',')
  # Propagate any client exceptions with a queue
  exception_queue = Queue.Queue()
  stop_event = threading.Event()
  hist = histogram.Histogram(1, 1)
  runners = []

  server = metrics_pb2.beta_create_MetricsService_server(
      metrics_server.MetricsServer(hist))
  server.add_insecure_port('[::]:{}'.format(args.metrics_port))
  server.start()

  for test_server in test_servers:
    host, port = test_server.split(':', 1)
    for _ in xrange(args.num_channels_per_server):
      channel = implementations.insecure_channel(host, int(port))
      for _ in xrange(args.num_stubs_per_channel):
        stub = test_pb2.beta_create_TestService_stub(channel)
        runner = test_runner.TestRunner(stub, test_cases, hist,
                                        exception_queue, stop_event)
        runners.append(runner)

  for runner in runners:
    runner.start()
  try:
    raise exception_queue.get(block=True, timeout=args.test_duration_secs)
  except Queue.Empty:
    # No exceptions thrown, success
    pass
  finally:
    stop_event.set()
    for runner in runners:
      runner.join()
      runner = None
    server.stop(0)

if __name__ == '__main__':
  run_test(_args())