# Copyright 2020 The 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.
"""The Python AsyncIO example of utilizing Channelz feature."""

import asyncio
import argparse
import logging
import random

import grpc

helloworld_pb2, helloworld_pb2_grpc = grpc.protos_and_services(
    "helloworld.proto")

# TODO: Suppress until the macOS segfault fix rolled out
from grpc_channelz.v1 import channelz  # pylint: disable=wrong-import-position

_LOGGER = logging.getLogger(__name__)
_LOGGER.setLevel(logging.INFO)

_RANDOM_FAILURE_RATE = 0.3


class FaultInjectGreeter(helloworld_pb2_grpc.GreeterServicer):

    def __init__(self, failure_rate):
        self._failure_rate = failure_rate

    async def SayHello(
            self, request: helloworld_pb2.HelloRequest,
            context: grpc.aio.ServicerContext) -> helloworld_pb2.HelloReply:
        if random.random() < self._failure_rate:
            context.abort(grpc.StatusCode.UNAVAILABLE,
                          'Randomly injected failure.')
        return helloworld_pb2.HelloReply(message=f'Hello, {request.name}!')


def create_server(addr: str, failure_rate: float) -> grpc.aio.Server:
    server = grpc.aio.server()
    helloworld_pb2_grpc.add_GreeterServicer_to_server(
        FaultInjectGreeter(failure_rate), server)

    # Add Channelz Servicer to the gRPC server
    channelz.add_channelz_servicer(server)

    server.add_insecure_port(addr)
    return server


async def main() -> None:
    parser = argparse.ArgumentParser()
    parser.add_argument('--addr',
                        nargs=1,
                        type=str,
                        default='[::]:50051',
                        help='the address to listen on')
    parser.add_argument(
        '--failure_rate',
        nargs=1,
        type=float,
        default=0.3,
        help='a float indicates the percentage of failed message injections')
    args = parser.parse_args()

    server = create_server(addr=args.addr, failure_rate=args.failure_rate)
    await server.start()
    await server.wait_for_termination()


if __name__ == '__main__':
    logging.basicConfig(level=logging.INFO)
    asyncio.get_event_loop().run_until_complete(main())