Getting Hands-On with Docker Multilang: Hello Worlds and Breaking Stuff

Why I Did It

I’d heard about Docker in class—like, it’s this tool that packs up code so it runs the same everywhere. I didn’t get it from slides, so I decided to try it myself. I picked Python and Node.js because I’d used them a bit—Python for some math stuff, Node.js for web APIs—and I wanted to see if I could make them talk in one project. My goal was simple: get two "hello worlds" running, one from each, and mess with them to learn how Docker works. It was for a school assignment, but I turned it into a playground.

How I Set It Up

I made two Docker containers:

• Python: A basic script (hello.py) that prints "Hello from Python!" when you run it.
• Node.js: A tiny Express server (app.js) that says "Hello from Node.js!" at localhost:3000.

Here’s what the Python one looked like:

print("Hello from Python!")

And the Node.js one:

const express = require('express');
const app = express();
app.get('/', (req, res) => res.send('Hello from Node.js!'));
app.listen(3000, () => console.log('Node.js running'));

I wrote Dockerfiles for each—super basic stuff like FROM python:3.9 and FROM node:14, copied the code in, and ran them with a docker-compose.yml file to tie them together. It took me a while to figure out the commands—like docker build and docker-compose up—but once it clicked, I was hooked.

Having Fun with Hello Worlds

The fun part was getting those "hello worlds" to pop up. I started with just running them—Python spat out its message in the terminal, Node.js showed up in my browser. Then I got curious: what if I made them say different stuff? I changed Python to "Yo, Python here!" and Node.js to "Hey, it’s Node.js!"—tested it, and laughed when they worked. I felt like a kid mixing colors, seeing what I could do. I even tried breaking them—like deleting express from Node.js—and Docker yelled at me with errors, which was awesome because I could see exactly what went wrong.

Use Cases I Figured Out

While I was playing, I started seeing why this could be useful:

• Testing Different Languages: I could test how Python and Node.js handle the same job—like a simple calculator—and compare them side-by-side. Python was cleaner for math, Node.js faster for web stuff.
• Breaking Stuff Safely: I could mess up one container—like crashing Node.js with a bad script—and the Python one still ran fine. It’s like having separate sandboxes.
• Real-World Setup: I pictured using this for a fitness app (like Johnson Health Tech’s stuff)—one part in Python for data crunching, another in Node.js for the web front. Docker keeps them together but separate.

For example, I tried a use case where Python counts to 10:

for i in range(10): print(f"Counting: {i}")

And Node.js echoes it back at /count. I broke the Node.js part by forgetting a comma—tested it, saw the error (SyntaxError), and fixed it. That’s when I got how Docker helps you isolate bugs.

Breaking Things Down Visually

The best part was how Docker made stuff visual. Running docker ps showed me both containers as little boxes—Python at one port, Node.js at another. When one crashed (like Node.js with no express), the other kept chugging along in the list. I could open my terminal, see logs with docker logs, and watch Python print "Hello" while Node.js barfed errors. It was like having a dashboard for my mess-ups. I even ran docker-compose up with a bad config—Python worked, Node.js didn’t—and the split made it so clear where I screwed up.

Why It Was Fun

I had a good time because it was like a game—get the "hello worlds" going, then break them and fix them. I’d run docker-compose up, see one fail, and dig into why—like Node.js not finding a file because I typo’d the path. I’d laugh when I broke it bad enough to get a blank screen, then feel smart when I got it back. It wasn’t about making something perfect; it was about learning what Docker does by seeing it work and fail.

What I Got Out of It

This project showed me how to package code, script basic tests (like docker exec to poke around), and see problems visually. It’s not a big deal—I’m no pro—but it’s real. I learned Docker’s useful for testing stuff like fitness apps without breaking everything at once. You can check it out at github.com/BradleyMatera/docker_multilang_project. It’s just a start, but it’s how I learn—by doing and breaking things.