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How to build and run a Node.js application using Nginx, Docker and Redis

Ajeet Raina
Author
Ajeet Raina, Former Developer Growth Manager at Redis

What do you need?#

  • •: An open-source, cross-platform, back-end JavaScript runtime environment that runs on the V8 engine and executes JavaScript code outside a web browser.
  • •: An open source software for web serving, reverse proxying, caching, load balancing, media streaming, and more.
  • •: a containerization platform for developing, shipping, and running applications.
  • •: A tool for defining and running multi-container Docker applications.

Project structure#

.
├── docker-compose.yml
├── redis
├── nginx
│   ├── Dockerfile
│   └── nginx.conf
├── web1
│   ├── Dockerfile
│   ├── package.json
│   └── server.js
└── web2
    ├── Dockerfile
    ├── package.json
    └── server.js

Prerequisites:#

INFO

Step 1. Create a Docker compose file#

version: '3.9'
services:
  redis:
    image: 'redis:alpine'
    ports:
      - '6379:6379'
  web1:
    restart: on-failure
    build: ./web
    hostname: web1
    ports:
      - '81:5000'
  web2:
    restart: on-failure
    build: ./web
    hostname: web2
    ports:
      - '82:5000'
  nginx:
    build: ./nginx
    ports:
    - '80:80'
    depends_on:
    - web1
    - web2
INFO

Step 2. Create an nginx directory and add the following files:#

File: nginx/nginx.conf

upstream loadbalancer {
  server web1:5000;
  server web2:5000;
}

server {
  listen 80;
  server_name localhost;
  location / {
    proxy_pass http://loadbalancer;
  }
}

File: Dockerfile

FROM nginx:1.21.6
RUN rm /etc/nginx/conf.d/default.conf
COPY nginx.conf /etc/nginx/conf.d/default.conf

Step 3. Create a web directory and add the following files:#

File: web/Dockerfile

FROM node:14.17.3-alpine3.14

WORKDIR /usr/src/app

COPY ./package.json ./
RUN npm install
COPY ./server.js ./

CMD ["npm","start"]

File: web/package.json


  "name": "web",
  "version": "1.0.0",
  "description": "Running Node.js and Express.js on Docker",
  "main": "server.js",
  "scripts": {
    "start": "node server.js"
  },
  "dependencies": {
    "express": "^4.17.2",
    "redis": "3.1.2"
  },
  "author": "",
  "license": "MIT"
}

File: web/server.js

const express = require('express');
const redis = require('redis');
const app = express();
const redisClient = redis.createClient({
  host: 'redis',
  port: 6379
});

app.get('/', function(req, res) {
    redisClient.get('numVisits', function(err, numVisits) {
        numVisitsToDisplay = parseInt(numVisits) + 1;
        if (isNaN(numVisitsToDisplay)) {
            numVisitsToDisplay = 1;
        }
        res.send('Number of visits is: ' + numVisitsToDisplay);
        numVisits++;
        redisClient.set('numVisits', numVisits);
    });
});

app.listen(5000, function() {
    console.log('Web application is listening on port 5000');
});

Step 4. Deploy the application#

$ docker-compose up -d
Creating nginx-nodejs-redis_redis_1 ... done
Creating nginx-nodejs-redis_web1_1  ... done
Creating nginx-nodejs-redis_web2_1  ... done
Creating nginx-nodejs-redis_nginx_1 ... done

Expected result

docker-compose ps
           Name                        Command              State           Ports
------------------------------------------------------------------------------------------
nginx-nodejs-redis_nginx_1   /docker-entrypoint.sh ngin     Up      0.0.0.0:80->80/tcp
                             ...
nginx-nodejs-redis_redis_1   docker-entrypoint.sh redis     Up      0.0.0.0:6379->6379/tcp
                             ...
nginx-nodejs-redis_web1_1    docker-entrypoint.sh npm       Up      0.0.0.0:81->5000/tcp
                             start
nginx-nodejs-redis_web2_1    docker-entrypoint.sh npm       Up      0.0.0.0:82->5000/tcp
                             start

Step 5. Testing the app#

curl localhost:80
curl localhost:80
web1: Total number of visits is: 1
curl localhost:80
web1: Total number of visits is: 2
$ curl localhost:80
web2: Total number of visits is: 3
$ curl localhost:80
web2: Total number of visits is: 4

Step 6. Monitoring Redis keys#

% redis-cli
127.0.0.1:6379> monitor
OK
1646485507.290868 [0 172.24.0.2:34330] "get" "numVisits"
1646485507.309070 [0 172.24.0.2:34330] "set" "numVisits" "5"
1646485509.228084 [0 172.24.0.2:34330] "get" "numVisits"
1646485509.241762 [0 172.24.0.2:34330] "set" "numVisits" "6"
1646485509.619369 [0 172.24.0.4:52082] "get" "numVisits"
1646485509.629739 [0 172.24.0.4:52082] "set" "numVisits" "7"
1646485509.990926 [0 172.24.0.2:34330] "get" "numVisits"
1646485509.999947 [0 172.24.0.2:34330] "set" "numVisits" "8"
1646485510.270934 [0 172.24.0.4:52082] "get" "numVisits"
1646485510.286785 [0 172.24.0.4:52082] "set" "numVisits" "9"
1646485510.469613 [0 172.24.0.2:34330] "get" "numVisits"
1646485510.480849 [0 172.24.0.2:34330] "set" "numVisits" "10"
1646485510.622615 [0 172.24.0.4:52082] "get" "numVisits"
1646485510.632720 [0 172.24.0.4:52082] "set" "numVisits" "11"

Further References#

Last updated on Mar 1, 2024
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