grpc/examples/python/cancellation/client.py

# Copyright the 2019 gRPC authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""An example of cancelling requests in gRPC."""

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

import argparse
import logging
import signal
import six
import threading

from six.moves.queue import Queue
from six.moves.queue import Empty as QueueEmpty

import grpc
import os
import sys

from examples.python.cancellation import hash_name_pb2
from examples.python.cancellation import hash_name_pb2_grpc

_DESCRIPTION = "A client for finding hashes similar to names."
_LOGGER = logging.getLogger(__name__)


def run_unary_client(server_target, name, ideal_distance):
    with grpc.insecure_channel(server_target) as channel:
        stub = hash_name_pb2_grpc.HashFinderStub(channel)
        future = stub.Find.future(
            hash_name_pb2.HashNameRequest(
                desired_name=name, ideal_hamming_distance=ideal_distance),
            wait_for_ready=True)

        def cancel_request(unused_signum, unused_frame):
            future.cancel()
            sys.exit(0)

        signal.signal(signal.SIGINT, cancel_request)
        result = future.result()
        print(result)


def run_streaming_client(server_target, name, ideal_distance,
                         interesting_distance):
    with grpc.insecure_channel(server_target) as channel:
        stub = hash_name_pb2_grpc.HashFinderStub(channel)
        result_generator = stub.FindRange(
            hash_name_pb2.HashNameRequest(
                desired_name=name,
                ideal_hamming_distance=ideal_distance,
                interesting_hamming_distance=interesting_distance),
            wait_for_ready=True)

        def cancel_request(unused_signum, unused_frame):
            result_generator.cancel()
            sys.exit(0)

        signal.signal(signal.SIGINT, cancel_request)
        for result in result_generator:
            print(result)


def main():
    parser = argparse.ArgumentParser(description=_DESCRIPTION)
    parser.add_argument("name", type=str, help='The desired name.')
    parser.add_argument(
        "--ideal-distance",
        default=0,
        nargs='?',
        type=int,
        help="The desired Hamming distance.")
    parser.add_argument(
        '--server',
        default='localhost:50051',
        type=str,
        nargs='?',
        help='The host-port pair at which to reach the server.')
    parser.add_argument(
        '--show-inferior',
        default=None,
        type=int,
        nargs='?',
        help='Also show candidates with a Hamming distance less than this value.'
    )

    args = parser.parse_args()
    if args.show_inferior is not None:
        run_streaming_client(args.server, args.name, args.ideal_distance,
                             args.show_inferior)
    else:
        run_unary_client(args.server, args.name, args.ideal_distance)


if __name__ == "__main__":
    logging.basicConfig()
    main()