examples/python/retry/retry_client.py

# Copyright 2021 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 implementation of the gRPC client-side retry example."""

import json
import logging

import grpc

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


def run():
    # The ServiceConfig proto definition can be found:
    # https://github.com/grpc/grpc-proto/blob/ec886024c2f7b7f597ba89d5b7d60c3f94627b17/grpc/service_config/service_config.proto#L377
    service_config_json = json.dumps({
        "methodConfig": [{
            # To apply retry to all methods, put [{}] in the "name" field
            "name": [{
                "service": "helloworld.Greeter",
                "method": "SayHello"
            }],
            "retryPolicy": {
                "maxAttempts": 5,
                "initialBackoff": "0.1s",
                "maxBackoff": "1s",
                "backoffMultiplier": 2,
                "retryableStatusCodes": ["UNAVAILABLE"],
            },
        }]
    })
    options = []
    # NOTE: the retry feature will be enabled by default >=v1.40.0
    options.append(("grpc.enable_retries", 1))
    options.append(("grpc.service_config", service_config_json))
    with grpc.insecure_channel('localhost:50051', options=options) as channel:
        stub = helloworld_pb2_grpc.GreeterStub(channel)
        response = stub.SayHello(helloworld_pb2.HelloRequest(name='you'))
    print("Greeter client received: " + response.message)


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