microservices-demo/src/currencyservice/server.js
Yoshi Yamaguchi 7f40378ecc log: change log format to JSON payload for better log in Stackdriver (#66)
change the log format in Python and Node.js services.

Effected services are currencyservice, emailservice, paymentservice,
and recommendationservice. Loadgenerator is left as is because of
the diffculty to change the log format and log target in locust.

ref. #47
2018-10-05 11:23:45 -07:00

182 lines
4.9 KiB
JavaScript

/*
* Copyright 2018 Google LLC.
*
* 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.
*/
require('@google-cloud/profiler').start({
serviceContext: {
service: 'currencyservice',
version: '1.0.0'
}
});
require('@google-cloud/trace-agent').start();
require('@google-cloud/debug-agent').start({
serviceContext: {
service: 'currencyservice',
version: 'VERSION'
}
});
const path = require('path');
const grpc = require('grpc');
const request = require('request');
const xml2js = require('xml2js');
const pino = require('pino');
const protoLoader = require('@grpc/proto-loader');
const MAIN_PROTO_PATH = path.join(__dirname, './proto/demo.proto');
const HEALTH_PROTO_PATH = path.join(__dirname, './proto/grpc/health/v1/health.proto');
const PORT = 7000;
const DATA_URL = 'http://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml';
const shopProto = _loadProto(MAIN_PROTO_PATH).hipstershop;
const healthProto = _loadProto(HEALTH_PROTO_PATH).grpc.health.v1;
const logger = pino({
name: 'currencyservice-server',
messageKey: 'message',
changeLevelName: 'severity',
useLevelLabels: true
});
/**
* Helper function that loads a protobuf file.
*/
function _loadProto (path) {
const packageDefinition = protoLoader.loadSync(
path,
{
keepCase: true,
longs: String,
enums: String,
defaults: true,
oneofs: true
}
);
return grpc.loadPackageDefinition(packageDefinition);
}
/**
* Helper function that gets currency data from an XML webpage
* Uses public data from European Central Bank
*/
let _data;
function _getCurrencyData (callback) {
if (!_data) {
logger.info('Fetching currency data...');
request(DATA_URL, (err, res) => {
if (err) {
throw new Error(`Error getting data: ${err}`);
}
const body = res.body.split('\n').slice(7, -2).join('\n');
xml2js.parseString(body, (err, resJs) => {
if (err) {
throw new Error(`Error parsing HTML: ${err}`);
}
const array = resJs['Cube']['Cube'].map(x => x['$']);
const results = array.reduce((acc, x) => {
acc[x['currency']] = x['rate'];
return acc;
}, { 'EUR': '1.0' });
_data = results;
callback(_data);
});
});
} else {
callback(_data);
}
}
/**
* Helper function that handles decimal/fractional carrying
*/
function _carry (amount) {
const fractionSize = Math.pow(10, 9);
amount.nanos += (amount.units % 1) * fractionSize;
amount.units = Math.floor(amount.units) + Math.floor(amount.nanos / fractionSize);
amount.nanos = amount.nanos % fractionSize;
return amount;
}
/**
* Lists the supported currencies
*/
function getSupportedCurrencies (call, callback) {
logger.info('Getting supported currencies...');
_getCurrencyData((data) => {
callback(null, {currency_codes: Object.keys(data)});
});
}
/**
* Converts between currencies
*/
function convert (call, callback) {
logger.info('received conversion request');
try {
_getCurrencyData((data) => {
const request = call.request;
// Convert: from_currency --> EUR
const from = request.from;
const euros = _carry({
units: from.units / data[from.currency_code],
nanos: from.nanos / data[from.currency_code]
});
euros.nanos = Math.round(euros.nanos);
// Convert: EUR --> to_currency
const result = _carry({
units: euros.units * data[request.to_code],
nanos: euros.nanos * data[request.to_code]
});
result.units = Math.floor(result.units);
result.nanos = Math.floor(result.nanos);
result.currency_code = request.to_code;
logger.info(`conversion request successful`);
callback(null, result);
});
} catch (err) {
logger.error(`conversion request failed: ${err}`);
callback(err.message);
}
}
/**
* Endpoint for health checks
*/
function check (call, callback) {
callback(null, { status: 'SERVING' });
}
/**
* Starts an RPC server that receives requests for the
* CurrencyConverter service at the sample server port
*/
function main () {
logger.info(`Starting gRPC server on port ${PORT}...`);
const server = new grpc.Server();
server.addService(shopProto.CurrencyService.service, {getSupportedCurrencies, convert});
server.addService(healthProto.Health.service, {check});
server.bind(`0.0.0.0:${PORT}`, grpc.ServerCredentials.createInsecure());
server.start();
}
main();