grpc-node/examples/load_balancing/client.js

76 lines
2.3 KiB
JavaScript

/*
*
* Copyright 2025 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.
*
*/
const grpc = require('@grpc/grpc-js');
const protoLoader = require('@grpc/proto-loader');
const PROTO_PATH = __dirname + '/../protos/echo.proto';
const packageDefinition = protoLoader.loadSync(
PROTO_PATH,
{keepCase: true,
longs: String,
enums: String,
defaults: true,
oneofs: true
});
const echoProto = grpc.loadPackageDefinition(packageDefinition).grpc.examples.echo;
const addressString = 'ipv4:///127.0.0.1:50051,127.0.0.1:50052';
function callUnaryEcho(client, message) {
return new Promise((resolve, reject) => {
const deadline = new Date();
deadline.setSeconds(deadline.getSeconds() + 1);
client.unaryEcho({message}, {deadline}, (error, response) => {
if (error) {
reject(error);
} else {
console.log(response.message);
resolve(response);
}
});
});
}
async function makeRPCs(client, count) {
for (let i = 0; i < count; i++) {
await callUnaryEcho(client, "this is examples/load_balancing");
}
}
async function main() {
// "pick_first" is the default, so there's no need to set the load balancing policy.
const pickFirstClient = new echoProto.Echo(addressString, grpc.credentials.createInsecure());
console.log("--- calling helloworld.Greeter/SayHello with pick_first ---");
await makeRPCs(pickFirstClient, 10);
console.log();
const roundRobinServiceConfig = {
methodConfig: [],
loadBalancingConfig: [{ round_robin: {} }]
};
const roundRobinClient = new echoProto.Echo(addressString, grpc.credentials.createInsecure(), {'grpc.service_config': JSON.stringify(roundRobinServiceConfig)});
console.log("--- calling helloworld.Greeter/SayHello with round_robin ---");
await makeRPCs(roundRobinClient, 10);
pickFirstClient.close();
roundRobinClient.close();
}
main();