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import argparse
import contextlib
import errno
import itertools
import os
import subprocess
import sys
import time
import unittest

from grpc.framework.face import exceptions
from grpc.framework.foundation import future

# Assigned in __main__.
_build_mode = None


class _ServicerMethods(object):

  def __init__(self, test_pb2, delay):
    self._paused = False
    self._failed = False
    self.test_pb2 = test_pb2
    self.delay = delay

  @contextlib.contextmanager
  def pause(self):  # pylint: disable=invalid-name
    self._paused = True
    yield
    self._paused = False

  @contextlib.contextmanager
  def fail(self):  # pylint: disable=invalid-name
    self._failed = True
    yield
    self._failed = False

  def _control(self):  # pylint: disable=invalid-name
    if self._failed:
      raise ValueError()
    time.sleep(self.delay)
    while self._paused:
      time.sleep(0)

  def UnaryCall(self, request):
    response = self.test_pb2.SimpleResponse()
    response.payload.payload_type = self.test_pb2.COMPRESSABLE
    response.payload.payload_compressable = 'a' * request.response_size
    self._control()
    return response

  def StreamingOutputCall(self, request):
    for parameter in request.response_parameters:
      response = self.test_pb2.StreamingOutputCallResponse()
      response.payload.payload_type = self.test_pb2.COMPRESSABLE
      response.payload.payload_compressable = 'a' * parameter.size
      self._control()
      yield response

  def StreamingInputCall(self, request_iter):
    response = self.test_pb2.StreamingInputCallResponse()
    aggregated_payload_size = 0
    for request in request_iter:
      aggregated_payload_size += len(request.payload.payload_compressable)
    response.aggregated_payload_size = aggregated_payload_size
    self._control()
    return response

  def FullDuplexCall(self, request_iter):
    for request in request_iter:
      for parameter in request.response_parameters:
        response = self.test_pb2.StreamingOutputCallResponse()
        response.payload.payload_type = self.test_pb2.COMPRESSABLE
        response.payload.payload_compressable = 'a' * parameter.size
        self._control()
        yield response

  def HalfDuplexCall(self, request_iter):
    responses = []
    for request in request_iter:
      for parameter in request.response_parameters:
        response = self.test_pb2.StreamingOutputCallResponse()
        response.payload.payload_type = self.test_pb2.COMPRESSABLE
        response.payload.payload_compressable = 'a' * parameter.size
        self._control()
        responses.append(response)
    for response in responses:
      yield response


def CreateService(test_pb2, delay=0, timeout=1):
  """Provides a servicer backend and a stub.

  The servicer is just the implementation
  of the actual servicer passed to the face player of the python RPC
  implementation; the two are detached.

  Non-zero delay puts a delay on each call to the servicer, representative of
  communication latency. Timeout is the default timeout for the stub while
  waiting for the service.

  Args:
    test_pb2: the test_pb2 module generated by this test
    delay: delay in seconds per response from the servicer
    timeout: how long the stub will wait for the servicer by default.
  Returns:
    A two-tuple (servicer, stub), where the servicer is the back-end of the
      service bound to the stub.
  """
  class Servicer(test_pb2.TestServiceServicer):

    def UnaryCall(self, request):
      return servicer_methods.UnaryCall(request)

    def StreamingOutputCall(self, request):
      return servicer_methods.StreamingOutputCall(request)

    def StreamingInputCall(self, request_iter):
      return servicer_methods.StreamingInputCall(request_iter)

    def FullDuplexCall(self, request_iter):
      return servicer_methods.FullDuplexCall(request_iter)

    def HalfDuplexCall(self, request_iter):
      return servicer_methods.HalfDuplexCall(request_iter)

  servicer_methods = _ServicerMethods(test_pb2, delay)
  servicer = Servicer()
  linked_pair = test_pb2.mock_TestService(servicer, timeout)
  stub = linked_pair.stub
  return servicer_methods, stub


def StreamingInputRequest(test_pb2):
  for _ in range(3):
    request = test_pb2.StreamingInputCallRequest()
    request.payload.payload_type = test_pb2.COMPRESSABLE
    request.payload.payload_compressable = 'a'
    yield request


def StreamingOutputRequest(test_pb2):
  request = test_pb2.StreamingOutputCallRequest()
  sizes = [1, 2, 3]
  request.response_parameters.add(size=sizes[0], interval_us=0)
  request.response_parameters.add(size=sizes[1], interval_us=0)
  request.response_parameters.add(size=sizes[2], interval_us=0)
  return request


def FullDuplexRequest(test_pb2):
  request = test_pb2.StreamingOutputCallRequest()
  request.response_parameters.add(size=1, interval_us=0)
  yield request
  request = test_pb2.StreamingOutputCallRequest()
  request.response_parameters.add(size=2, interval_us=0)
  request.response_parameters.add(size=3, interval_us=0)
  yield request


class PythonPluginTest(unittest.TestCase):
  """Test case for the gRPC Python protoc-plugin.

  While reading these tests, remember that the futures API
  (`stub.method.async()`) only gives futures for the *non-streaming* responses,
  else it behaves like its blocking cousin.
  """

  def setUp(self):
    protoc_command = '../../bins/%s/protobuf/protoc' % _build_mode
    protoc_plugin_filename = '../../bins/%s/grpc_python_plugin' % _build_mode
    test_proto_filename = '../cpp/interop/test.proto'
    if not os.path.isfile(protoc_command):
      # Assume that if we haven't built protoc that it's on the system.
      protoc_command = 'protoc'

    # ensure that the output directory exists
    outdir = '../../gens/test/compiler/python/'
    try:
      os.makedirs(outdir)
    except OSError as exception:
      if exception.errno != errno.EEXIST:
        raise

    cmd = [
        protoc_command,
        '--plugin=protoc-gen-python-grpc=%s' % protoc_plugin_filename,
        '-I %s' % os.path.dirname(test_proto_filename),
        '--python_out=%s' % outdir,
        '--python-grpc_out=%s' % outdir,
        os.path.basename(test_proto_filename),
    ]
    subprocess.call(' '.join(cmd), shell=True)
    sys.path.append(outdir)

    self.delay = 1  # seconds
    self.timeout = 2  # seconds

  def testImportAttributes(self):
    # check that we can access the members
    import test_pb2  # pylint: disable=g-import-not-at-top
    self.assertIsNotNone(getattr(test_pb2, 'TestServiceServicer', None))
    self.assertIsNotNone(getattr(test_pb2, 'TestServiceService', None))
    self.assertIsNotNone(getattr(test_pb2, 'TestServiceStub', None))

  def testUnaryCall(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    servicer, stub = CreateService(test_pb2)
    request = test_pb2.SimpleRequest(response_size=13)
    response = stub.UnaryCall(request)
    expected_response = servicer.UnaryCall(request)
    self.assertEqual(expected_response, response)

  def testUnaryCallAsync(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    servicer, stub = CreateService(
        test_pb2, delay=self.delay, timeout=self.timeout)
    request = test_pb2.SimpleRequest(response_size=13)
    # TODO(atash): consider using the 'profile' module? Does it even work here?
    start_time = time.clock()
    response_future = stub.UnaryCall.async(request)
    self.assertGreater(self.delay, time.clock() - start_time)
    response = response_future.result()
    expected_response = servicer.UnaryCall(request)
    self.assertEqual(expected_response, response)

  def testUnaryCallAsyncExpired(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    # set the timeout super low...
    servicer, stub = CreateService(test_pb2, delay=1, timeout=0.1)
    request = test_pb2.SimpleRequest(response_size=13)
    with servicer.pause():
      response_future = stub.UnaryCall.async(request)
      with self.assertRaises(exceptions.ExpirationError):
        response_future.result()

  def testUnaryCallAsyncCancelled(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    servicer, stub = CreateService(test_pb2)
    request = test_pb2.SimpleRequest(response_size=13)
    with servicer.pause():
      response_future = stub.UnaryCall.async(request)
      response_future.cancel()
      self.assertTrue(response_future.cancelled())

  def testUnaryCallAsyncFailed(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    servicer, stub = CreateService(test_pb2)
    request = test_pb2.SimpleRequest(response_size=13)
    with servicer.fail():
      response_future = stub.UnaryCall.async(request)
      self.assertIsNotNone(response_future.exception())

  def testStreamingOutputCall(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    servicer, stub = CreateService(test_pb2)
    request = StreamingOutputRequest(test_pb2)
    responses = stub.StreamingOutputCall(request)
    expected_responses = servicer.StreamingOutputCall(request)
    for check in itertools.izip_longest(expected_responses, responses):
      expected_response, response = check
      self.assertEqual(expected_response, response)

  def testStreamingOutputCallAsync(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    servicer, stub = CreateService(test_pb2, timeout=self.timeout)
    request = StreamingOutputRequest(test_pb2)
    responses = stub.StreamingOutputCall.async(request)
    expected_responses = servicer.StreamingOutputCall(request)
    for check in itertools.izip_longest(expected_responses, responses):
      expected_response, response = check
      self.assertEqual(expected_response, response)

  def testStreamingOutputCallAsyncExpired(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    servicer, stub = CreateService(test_pb2, timeout=0.1)
    request = StreamingOutputRequest(test_pb2)
    with servicer.pause():
      responses = stub.StreamingOutputCall.async(request)
      with self.assertRaises(exceptions.ExpirationError):
        list(responses)

  def testStreamingOutputCallAsyncCancelled(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    _, stub = CreateService(test_pb2, timeout=0.1)
    request = StreamingOutputRequest(test_pb2)
    responses = stub.StreamingOutputCall.async(request)
    next(responses)
    responses.cancel()
    with self.assertRaises(future.CancelledError):
      next(responses)

  def testStreamingOutputCallAsyncFailed(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    servicer, stub = CreateService(test_pb2, timeout=0.1)
    request = StreamingOutputRequest(test_pb2)
    with servicer.fail():
      responses = stub.StreamingOutputCall.async(request)
      self.assertIsNotNone(responses)
      with self.assertRaises(exceptions.ServicerError):
        next(responses)

  def testStreamingInputCall(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    servicer, stub = CreateService(test_pb2)
    response = stub.StreamingInputCall(StreamingInputRequest(test_pb2))
    expected_response = servicer.StreamingInputCall(
        StreamingInputRequest(test_pb2))
    self.assertEqual(expected_response, response)

  def testStreamingInputCallAsync(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    servicer, stub = CreateService(
        test_pb2, delay=self.delay, timeout=self.timeout)
    start_time = time.clock()
    response_future = stub.StreamingInputCall.async(
        StreamingInputRequest(test_pb2))
    self.assertGreater(self.delay, time.clock() - start_time)
    response = response_future.result()
    expected_response = servicer.StreamingInputCall(
        StreamingInputRequest(test_pb2))
    self.assertEqual(expected_response, response)

  def testStreamingInputCallAsyncExpired(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    # set the timeout super low...
    servicer, stub = CreateService(test_pb2, delay=1, timeout=0.1)
    with servicer.pause():
      response_future = stub.StreamingInputCall.async(
          StreamingInputRequest(test_pb2))
      with self.assertRaises(exceptions.ExpirationError):
        response_future.result()
      self.assertIsInstance(
          response_future.exception(), exceptions.ExpirationError)

  def testStreamingInputCallAsyncCancelled(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    servicer, stub = CreateService(test_pb2)
    with servicer.pause():
      response_future = stub.StreamingInputCall.async(
          StreamingInputRequest(test_pb2))
      response_future.cancel()
      self.assertTrue(response_future.cancelled())
    with self.assertRaises(future.CancelledError):
      response_future.result()

  def testStreamingInputCallAsyncFailed(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    servicer, stub = CreateService(test_pb2)
    with servicer.fail():
      response_future = stub.StreamingInputCall.async(
          StreamingInputRequest(test_pb2))
      self.assertIsNotNone(response_future.exception())

  def testFullDuplexCall(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    servicer, stub = CreateService(test_pb2)
    responses = stub.FullDuplexCall(FullDuplexRequest(test_pb2))
    expected_responses = servicer.FullDuplexCall(FullDuplexRequest(test_pb2))
    for check in itertools.izip_longest(expected_responses, responses):
      expected_response, response = check
      self.assertEqual(expected_response, response)

  def testFullDuplexCallAsync(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    servicer, stub = CreateService(test_pb2, timeout=self.timeout)
    responses = stub.FullDuplexCall.async(FullDuplexRequest(test_pb2))
    expected_responses = servicer.FullDuplexCall(FullDuplexRequest(test_pb2))
    for check in itertools.izip_longest(expected_responses, responses):
      expected_response, response = check
      self.assertEqual(expected_response, response)

  def testFullDuplexCallAsyncExpired(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    servicer, stub = CreateService(test_pb2, timeout=0.1)
    request = FullDuplexRequest(test_pb2)
    with servicer.pause():
      responses = stub.FullDuplexCall.async(request)
      with self.assertRaises(exceptions.ExpirationError):
        list(responses)

  def testFullDuplexCallAsyncCancelled(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    _, stub = CreateService(test_pb2, timeout=0.1)
    request = FullDuplexRequest(test_pb2)
    responses = stub.FullDuplexCall.async(request)
    next(responses)
    responses.cancel()
    with self.assertRaises(future.CancelledError):
      next(responses)

  def testFullDuplexCallAsyncFailed(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    servicer, stub = CreateService(test_pb2, timeout=0.1)
    request = FullDuplexRequest(test_pb2)
    with servicer.fail():
      responses = stub.FullDuplexCall.async(request)
      self.assertIsNotNone(responses)
      with self.assertRaises(exceptions.ServicerError):
        next(responses)

  def testHalfDuplexCall(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    servicer, stub = CreateService(test_pb2)
    def HalfDuplexRequest():
      request = test_pb2.StreamingOutputCallRequest()
      request.response_parameters.add(size=1, interval_us=0)
      yield request
      request = test_pb2.StreamingOutputCallRequest()
      request.response_parameters.add(size=2, interval_us=0)
      request.response_parameters.add(size=3, interval_us=0)
      yield request
    responses = stub.HalfDuplexCall(HalfDuplexRequest())
    expected_responses = servicer.HalfDuplexCall(HalfDuplexRequest())
    for check in itertools.izip_longest(expected_responses, responses):
      expected_response, response = check
      self.assertEqual(expected_response, response)

  def testHalfDuplexCallAsyncWedged(self):
    import test_pb2  # pylint: disable=g-import-not-at-top
    _, stub = CreateService(test_pb2, timeout=1)
    wait_flag = [False]
    @contextlib.contextmanager
    def wait():  # pylint: disable=invalid-name
      # Where's Python 3's 'nonlocal' statement when you need it?
      wait_flag[0] = True
      yield
      wait_flag[0] = False
    def HalfDuplexRequest():
      request = test_pb2.StreamingOutputCallRequest()
      request.response_parameters.add(size=1, interval_us=0)
      yield request
      while wait_flag[0]:
        time.sleep(0.1)
    with wait():
      responses = stub.HalfDuplexCall.async(HalfDuplexRequest())
      # half-duplex waits for the client to send all info
      with self.assertRaises(exceptions.ExpirationError):
        next(responses)


if __name__ == '__main__':
  os.chdir(os.path.dirname(sys.argv[0]))
  parser = argparse.ArgumentParser(description='Run Python compiler plugin test.')
  parser.add_argument('--build_mode', dest='build_mode', type=str, default='dbg',
                      help='The build mode of the targets to test, e.g. '
                      '"dbg", "opt", "asan", etc.')
  args, remainder = parser.parse_known_args()
  _build_mode = args.build_mode
  sys.argv[1:] = remainder
  unittest.main()