Python の gRPC で Redis のデータを読む (Read)

設定ファイル、サーバープログラム、クライアントプログラムの３つが必要です。

設定ファイル

redis_read.proto

syntax = "proto3";

package redis_read;

service Greeter {
    rpc RedisRead (RedisRequest) returns (RedisReply) {}
}

message RedisRequest {
    string key = 1;
}

message RedisReply {
    string str_json = 1;
}

サーバープログラム

redis_read_server.py

#! /usr/bin/python
#
#   redis_read_server.py
#
#                   Feb/08/2020
# --------------------------------------------------------------
import sys
import redis
from concurrent import futures
import logging

import grpc

import redis_read_pb2
import redis_read_pb2_grpc

# --------------------------------------------------------------
def read_redis_proc(key_in):
    rr = redis.Redis(host='localhost', port=6379, db=0)
#
    str_json = rr.get(key_in).decode ()
#
    return str_json
# --------------------------------------------------------------
class Greeter(redis_read_pb2_grpc.GreeterServicer):

    def RedisRead(self, request, context):
        sys.stderr.write("*** RedisRead ***\n")
        sys.stderr.write("*** key = %s ***\n" % request.key)
        str_out_aa = read_redis_proc(request.key)
        sys.stderr.write(str_out_aa + "\n")
        return redis_read_pb2.RedisReply(str_json=str_out_aa)

# --------------------------------------------------------------
def serve():
    server = grpc.server(futures.ThreadPoolExecutor(max_workers=10))
    redis_read_pb2_grpc.add_GreeterServicer_to_server(Greeter(), server)
    server.add_insecure_port('[::]:50051')
    server.start()
    server.wait_for_termination()

# --------------------------------------------------------------
if __name__ == '__main__':
    logging.basicConfig()
    serve()
# --------------------------------------------------------------

クライアントプログラム

redis_read_client.py

#! /usr/bin/python
#
#   redis_read_client.py
#
#                   Feb/08/2020
#
# --------------------------------------------------------------
from __future__ import print_function
import logging
import json
import grpc
import sys

import redis_read_pb2
import redis_read_pb2_grpc

# --------------------------------------------------------------
def display_proc(str_json):
    unit_aa = json.loads(str_json)
    str_out = unit_aa['name']
    str_out += "\t"+ str(unit_aa['population'])
    str_out += "\t"+ unit_aa['date_mod']
    print(str_out)
#
# --------------------------------------------------------------
def run():
    key_in = sys.argv[1]
    with grpc.insecure_channel('localhost:50051') as channel:
        stub = redis_read_pb2_grpc.GreeterStub(channel)
        response = stub.RedisRead(redis_read_pb2.RedisRequest(key=key_in))
#       print("Greeter client received aa: " + response.str_json)
        display_proc(response.str_json)
#
# --------------------------------------------------------------
if __name__ == '__main__':
    logging.basicConfig()
    run()
# --------------------------------------------------------------

gRPC のコードを作成します。

python -m grpc_tools.protoc -I. \
    --python_out=. \
    --grpc_python_out=. \
    ./redis_read.proto

サーバープログラムの起動

./redis_read_server.py

クライアントプログラムの実行

$ ./redis_read_client.py t1854
大野  89612   2003-9-9