Minimal Compose app to upload/download a file

compose.yaml

services:
  service1:
    restart: always
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - mode: ingress
        target: 3000
        published: 3000
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:3000/"]

Dockerfile

# Use an official Node runtime based on slim as a parent image
FROM node:20-slim

# Set the working directory to /app
WORKDIR /app

# Install curl and any other dependencies
RUN apt-get update \
    \
    && apt-get install -y --no-install-recommends \
        curl \
    && rm -rf /var/lib/apt/lists/*

# Copy package.json and package-lock.json into the container at /app
COPY package*.json ./

# Install any needed packages specified in package.json
RUN npm install

# Copy the current directory contents into the container
COPY . .

# Make port 3000 available to the world outside this container
EXPOSE 3000

# Run the app when the container launches
ENTRYPOINT [ "node", "main.js" ]

main.js

const express = require('express');
const multer = require('multer');
const fs = require('fs');
const path = require('path');

const app = express();
const upload = multer({ dest: 'uploads/' });

app.use(express.static('uploads'));

app.get('/', (req, res) => {
    fs.readdir('uploads', (err, files) => {
        if (err) {
            return res.status(500).send('Unable to scan files!');
        }
        let fileList = files.map(file => `<li><a href="/${file}">${file}</a></li>`).join('');
        res.send(`
            <h1>File Upload</h1>
            <form ref='uploadForm' 
                id='uploadForm' 
                action='/' 
                method='post' 
                encType="multipart/form-data">
                <input type="file" name="file" />
                <input type='submit' value='Upload!' />
            </form>
            <h2>Uploaded Files</h2>
            <ul>${fileList}</ul>
        `);
    });
});

app.post('/', upload.single('file'), (req, res) => {
    res.redirect('/');
});

app.listen(3000, () => {
    console.log('Server started on port 3000');
});

package.json

{
  "name": "service1",
  "version": "1.0.0",
  "description": "",
  "main": "main.js",
  "scripts": {
    "start": "exec node main.js"
  },
  "dependencies": {
    "express": "^4.17.1",
    "multer": "^1.4.4"
  }
}