feat(examples): Add nginx-nodejs-redis compose example

This example was derived from the analog example from docker/awesome-compose.

Author: LucaSeri

examples/compose/nginx-nodejs-redis/README.md

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+## Compose sample application
+
+## Node.js application with Nginx proxy and Redis database
+
+This example was derived from the [nginx-nodejs-redis docker/awesome-compose example](https://github.com/docker/awesome-compose/tree/master/nginx-nodejs-redis).
+
+Project structure:
+```
+.
+├── README.md
+├── compose.yaml
+├── nginx
+│   └── nginx.conf
+└── web
+    ├── Kraftfile
+    ├── Dockerfile
+    ├── package.json
+    └── server.js
+
+2 directories, 7 files
+
+
+```
+[_compose.yaml_](compose.yaml)
+```
+services:
+  redis:
+    image: redis:7.2
+    ports:
+      - '6379:6379'
+    networks:
+      internal:
+        ipv4_address: 172.23.0.2
+    mem_reservation: 512M
+
+  web1:
+    build: ./web
+    hostname: web1
+    networks:
+      internal:
+        ipv4_address: 172.23.0.3
+    mem_reservation: 512M
+    depends_on:
+      - redis
+
+  web2:
+    build: ./web
+    hostname: web2
+    networks:
+      internal:
+        ipv4_address: 172.23.0.4
+    mem_reservation: 512M
+    depends_on:
+      - redis
+
+  nginx:
+    image: nginx:1.25
+    ports:
+    - '8080:80'
+    volumes:
+      - ./nginx:/etc/nginx
+    depends_on:
+    - web1
+    - web2
+    networks:
+      internal:
+
+networks:
+  internal:
+    ipam:
+      config:
+        - subnet: 172.23.0.1/16
+```
+The compose file defines an application with four services `redis`, `nginx`, `web1` and `web2`.
+When deploying the application, docker compose maps port 80 of the nginx service VM to port 8080 of the host as specified in the file.
+
+
+> **_INFO_**  
+> Redis runs on port 6379 by default. Make sure port 6379 on the host is not being used by another VM, otherwise the port should be changed.
+
+## Deploy with kraft compose
+
+```
+$ kraft compose up -d
+nginx-nodejs-redis-redis
+nginx-nodejs-redis-web1
+nginx-nodejs-redis-web2
+nginx-nodejs-redis-nginx
+```
+
+
+## Expected result
+
+Listing VMs must show four VMs running and the port mapping as below:
+
+
+```
+$ kraft compose ps
+NAME                      KERNEL                      ARGS                                         CREATED        STATUS   MEM   PORTS                   PLAT
+nginx-nodejs-redis-nginx  oci://nginx:1.25            /usr/bin/nginx                               2 minutes ago  running  64M   0.0.0.0:8080->80/tcp    qemu/x86_64
+nginx-nodejs-redis-redis  oci://redis:7.2             /usr/bin/redis-server /etc/redis/redis.conf  2 minutes ago  running  512M  0.0.0.0:6379->6379/tcp  qemu/x86_64
+nginx-nodejs-redis-web1   oci://unikraft.org/node:21  /usr/bin/node /usr/src/server.js             2 minutes ago  running  512M                          qemu/x86_64
+nginx-nodejs-redis-web2   oci://unikraft.org/node:21  /usr/bin/node /usr/src/server.js             2 minutes ago  running  512M                          qemu/x86_64
+```
+
+## Testing the app
+
+After the application starts, navigate to `http://localhost:8080` in your web browser or run:
+
+```
+curl localhost:8080
+web1: Total number of visits is: 1
+```
+
+```
+curl localhost:8080
+web2: Total number of visits is: 2
+```
+
+```
+$ curl localhost:8080
+web1: Total number of visits is: 3
+```
+
+## Stop and remove the VMs
+
+```
+$ kraft compose down
+```

examples/compose/nginx-nodejs-redis/compose.yaml

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+services:
+  redis:
+    image: redis:7.2
+    ports:
+      - '6379:6379'
+    networks:
+      internal:
+        ipv4_address: 172.23.0.2
+    mem_reservation: 512M
+
+  web1:
+    build: ./web
+    hostname: web1
+    networks:
+      internal:
+        ipv4_address: 172.23.0.3
+    mem_reservation: 512M
+    depends_on:
+      - redis
+
+  web2:
+    build: ./web
+    hostname: web2
+    networks:
+      internal:
+        ipv4_address: 172.23.0.4
+    mem_reservation: 512M
+    depends_on:
+      - redis
+
+  nginx:
+    image: nginx:1.25
+    ports:
+    - '8080:80'
+    volumes:
+      - ./nginx:/etc/nginx
+    depends_on:
+    - web1
+    - web2
+    networks:
+      internal:
+
+networks:
+  internal:
+    ipam:
+      config:
+        - subnet: 172.23.0.1/16
+

examples/compose/nginx-nodejs-redis/nginx/nginx.conf

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+worker_processes 1;
+daemon off;
+master_process off;
+user root root;
+
+events {
+  worker_connections 32;
+}
+
+http {
+  error_log stderr error;
+  access_log off;
+  
+  keepalive_timeout     10s;
+  keepalive_requests    10000;
+  send_timeout          10s;
+
+  upstream backend_servers {
+    server 172.23.0.3:5000;
+    server 172.23.0.4:5000;
+  }
+
+  server {
+    listen 80;
+    server_name localhost;
+
+    location / {
+      proxy_pass http://backend_servers;
+    }
+  }
+}

examples/compose/nginx-nodejs-redis/web/.gitignore

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+node_modules

examples/compose/nginx-nodejs-redis/web/Dockerfile

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+FROM node:21-alpine AS build
+
+WORKDIR /usr/src
+
+COPY . /usr/src/
+RUN npm install 
+
+FROM scratch
+
+COPY --from=build /etc/os-release /etc/os-release
+COPY --from=build /usr/src/node_modules /usr/src/node_modules
+COPY --from=build /usr/src/server.js /usr/src/server.js

examples/compose/nginx-nodejs-redis/web/Kraftfile

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+spec: v0.6
+
+runtime: node:21
+
+rootfs: ./Dockerfile
+
+cmd: ["/usr/bin/node", "/usr/src/server.js"]

examples/compose/nginx-nodejs-redis/web/package-lock.json

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+{
+  "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"
+}

examples/compose/nginx-nodejs-redis/web/package.json

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+const os = require('os');
+const express = require('express');
+const app = express();
+const redis = require('redis');
+const redisClient = redis.createClient({
+  host: '172.23.0.2',
+  port: 6379
+});
+
+app.get('/', function(req, res) {
+    redisClient.get('numVisits', function(err, numVisits) {
+        numVisitsToDisplay = parseInt(numVisits) + 1;
+        if (isNaN(numVisitsToDisplay)) {
+            numVisitsToDisplay = 1;
+        }
+       res.send(os.hostname() +': Number of visits is: ' + numVisitsToDisplay);
+        numVisits++;
+        redisClient.set('numVisits', numVisits);
+    });
+});
+
+app.listen(5000, function() {
+    console.log('Web application is listening on port 5000');
+});