How to use Memcache in Google Cloud App Engine for Node.js

Question

I'am try to setup an express service on gcloud standard app engine. I'would like to use memcache for session caching.

Did someone cann help me, how i connect the service to the memcache?

my Code is:

var session = require('express-session')
var MemcachedStore = require('connect-memcached')(session);
app.use(session({
  secret: 'appengineFTW',
  key: 'a_key',
  resave: true,
  store: new MemcachedStore({
      hosts: [process.env.MEMCACHE_URL || '127.0.0.1:11211']
  }),
  saveUninitialized: false
}));

The MEMCACHE_URL in prod is set to memcache:11211

Err: connect ECONNREFUSED 127.0.0.1:11211

Answer 1

1.Create a server folder.

mkdir server
cd server

2.Copy the server.js file into the folder

const express = require('express');
const session = require('express-session');
const cookieParser = require('cookie-parser');
const MemcachedStore = require('connect-memjs')(session);
const publicIp = require('public-ip');
const crypto = require('crypto');

// Environment variables are defined in app.yaml.
let MEMCACHE_URL = process.env.MEMCACHE_URL || '127.0.0.1:11211';

if (process.env.USE_GAE_MEMCACHE) {
  MEMCACHE_URL = `${process.env.GAE_MEMCACHE_HOST}:${process.env.GAE_MEMCACHE_PORT}`;
}

const app = express();
app.enable('trust proxy');

app.use(cookieParser());
app.use(session({
  secret: 'your-secret-here',
  key: 'view:count',
  proxy: 'true',
  store: new MemcachedStore({
    servers: [MEMCACHE_URL]
  })
}));

app.get('/', (req, res, next) => {
  // Discover requester's public IP address
  publicIp.v4().then((ip) => {
    const userIp = crypto.createHash('sha256').update(ip).digest('hex').substr(0, 7);

    // This shows the hashed IP for each
    res.write(`<div>${userIp}</div>`);

    if (req.session.views) {
      req.session.views += 1;
    } else {
      req.session.views = 1;
    }
    res.end(`Viewed <strong>${req.session.views}</strong> times.`);
  }).catch(next);
});

const PORT = process.env.PORT || 8080;
app.listen(PORT, () => {
  console.log('App listening on port %s', PORT);
  console.log('Press Ctrl+C to quit.');
});

module.exports = app;

3.Create a package.json file with NPM or Yarn:

npm init

4.Install dependencies with NPM or Yarn:

npm install --save connect-memjs cookie-parser express express-session public-ip

5.Create a memcached instance in the same region as your app engine application ( gcloud app describe to find the region). Write down the IP address of one of your nodes.

6.Create a app.yaml file

runtime: nodejs
env: flex

env_variables:

  MEMCACHE_URL: 10.10.10.10:11211 #your memcached instance ip

7.Deploy the application to App Engine Flex

gcloud app deploy gcloud app browse

8. Visit http://YOUR_PROJECT_ID.appspot.com to see the deployed app.