grpc/examples/python/errors/server.py

# Copyright 2019 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.
"""This example sends out rich error status from server-side."""

from concurrent import futures
import logging
import threading

import grpc
from grpc_status import rpc_status

from google.protobuf import any_pb2
from google.rpc import code_pb2, status_pb2, error_details_pb2

from examples import helloworld_pb2
from examples import helloworld_pb2_grpc


def create_greet_limit_exceed_error_status(name):
    detail = any_pb2.Any()
    detail.Pack(
        error_details_pb2.QuotaFailure(
            violations=[
                error_details_pb2.QuotaFailure.Violation(
                    subject="name: %s" % name,
                    description="Limit one greeting per person",
                )
            ],))
    return status_pb2.Status(
        code=code_pb2.RESOURCE_EXHAUSTED,
        message='Request limit exceeded.',
        details=[detail],
    )


class LimitedGreeter(helloworld_pb2_grpc.GreeterServicer):

    def __init__(self):
        self._lock = threading.RLock()
        self._greeted = set()

    def SayHello(self, request, context):
        with self._lock:
            if request.name in self._greeted:
                rich_status = create_greet_limit_exceed_error_status(
                    request.name)
                context.abort_with_status(rpc_status.to_status(rich_status))
            else:
                self._greeted.add(request.name)
        return helloworld_pb2.HelloReply(message='Hello, %s!' % request.name)


def create_server(server_address):
    server = grpc.server(futures.ThreadPoolExecutor())
    helloworld_pb2_grpc.add_GreeterServicer_to_server(LimitedGreeter(), server)
    port = server.add_insecure_port(server_address)
    return server, port


def serve(server):
    server.start()
    server.wait_for_termination()


def main():
    server, unused_port = create_server('[::]:50051')
    serve(server)


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