casa-account-server.js

// very bad nodejs code below...sorry...

// google tracer works, opencensus-exporter-stackdriver is
// doesn't work when deployed in GKE, not sure why
const useStackdriver = (() => {
    let env = process.env.USE_STACKDRIVER;
    return env && (env === "yes" || env === "true");
})();

if (useStackdriver) {
    require("@google-cloud/trace-agent").start({
        samplingRate: 1000, // max that GCP allows
        logLevel: 3, // info
    });
    console.log("google cloud trace agent initialized");
}

const fs = require("fs");
const path = require("path");
const _ = require("lodash");
// gRPC stuff
const grpc = require("grpc");
const protoLoader = require("@grpc/proto-loader");
const health = require("grpc-health-check");

function initZipkinTracing() {
    // opencensus stuff
    const {logger} = require("@opencensus/core");
    const tracing = require("@opencensus/nodejs");
    const {plugin} = require("@opencensus/instrumentation-grpc");
    const {ZipkinTraceExporter} = require("@opencensus/exporter-zipkin");

    zipkinUrl = process.env.ZIPKIN_COLLECTOR_URL;
    if (!zipkinUrl || zipkinUrl === "off") {
        console.log("jaeger exporter not initialized");
        return undefined;
    }

    const exporter = new ZipkinTraceExporter({
        url: zipkinUrl,
        serviceName: "casa-account-v2",
        tags: [
            {
                key: "runtime",
                value: "nodejs " + process.versions.node,
            },
            {
                key: "service",
                value: "casa-account-v2",
            },
        ],
        bufferTimeout: 10, // time in milliseconds
        logger: logger.logger("info"),
    });

    tracing.registerExporter(exporter).start({
        samplingRate: 1,
        logLevel: 1,
    });

    const basedir = path.dirname(require.resolve("grpc"));
    const version = require(path.join(basedir, "package.json")).version;

    // Enables GRPC plugin: Method that enables the instrumentation patch.
    plugin.enable(
        grpc,
        tracing.tracer,
        version,
        /** plugin options */ {},
        basedir
    );

    console.log("jaeger tracing initialized");
}

// dynamically load proto files and generates structure
// in memory. not using code generated by protoc here
let PROTO_PATH = __dirname + "/demo_bank.proto";
let packageDefinition = protoLoader.loadSync(PROTO_PATH, {
    keepCase: true,
    longs: String,
    enums: String,
    defaults: true,
    oneofs: true,
});
let api = grpc.loadPackageDefinition(packageDefinition).demobank.api;

function dummyCasaAccount(call, callback) {
    let lastUpdate = {
        seconds: Math.floor(new Date(2020, 4, 31, 18, 19, 20, 0) / 1000 + 3600 * 8),
        nanos: 0,
    };
    let dummy = Object.assign(
        {
            account_id: "00000000",
            nickname: "dummy-v2",
            prod_code: "1111",
            prod_name: "Bottomless CASA",
            currency: "SGD",
            status: "DORMANT",
            status_last_updated: lastUpdate,
            balances: [
                {
                    amount: 10.0,
                    type: "CURRENT",
                    credit_flag: true,
                    last_updated: lastUpdate,
                },
                {
                    amount: 10.0,
                    type: "AVAILABLE",
                    credit_flag: true,
                    last_updated: lastUpdate,
                },
            ],
        },
        api.CasaAccount
    );

    console.log("returning dummy account data");

    callback(null, dummy);
}

function getServer() {
    let server = new grpc.Server();

    server.addService(
        health.service,
        new health.Implementation({
            "": proto.grpc.health.v1.HealthCheckResponse.ServingStatus.SERVING,
        })
    );

    server.addService(api.CasaAccountService.service, {
        GetAccount: dummyCasaAccount,
    });

    return server;
}

if (require.main === module) {
    if (!useStackdriver) {
        initZipkinTracing();
    }

    let addr = process.env.GRPC_LISTEN_ADDR;
    if (!addr) {
        addr = "0.0.0.0:50051";
    }
    console.log("starting server listening on ", addr);

    let server = getServer();
    server.bind(addr, grpc.ServerCredentials.createInsecure());
    server.start();
}

exports.getServer = getServer;