https://github.com/julie-ng/hello-welt
Simple containerized Node.js app for demos.
https://github.com/julie-ng/hello-welt
containers docker fastifyjs nodejs
Last synced: over 1 year ago
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Simple containerized Node.js app for demos.
- Host: GitHub
- URL: https://github.com/julie-ng/hello-welt
- Owner: julie-ng
- License: mit
- Created: 2021-03-17T05:49:38.000Z (over 5 years ago)
- Default Branch: main
- Last Pushed: 2025-03-15T02:16:47.000Z (over 1 year ago)
- Last Synced: 2025-03-25T12:51:22.796Z (over 1 year ago)
- Topics: containers, docker, fastifyjs, nodejs
- Language: JavaScript
- Homepage:
- Size: 809 KB
- Stars: 7
- Watchers: 2
- Forks: 0
- Open Issues: 5
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
README
# Hello Welt
Simple Hello World [Fastify](https://www.fastify.io/) Node.js app with [JSON based logging](https://getpino.io/) incl. log levels, graceful shutdown, readiness probes and built-in crash triggers, etc. for container orchestration demos.
[](https://github.com/julie-ng/hello-welt/actions/workflows/ci.yaml)
[](https://github.com/julie-ng/hello-welt/actions/workflows/docker.yaml)
[](https://snyk.io/test/github/julie-ng/hello-welt)
# Configuration
The following variables can be configured
| Environment Variable | Default |
|:--|:--|
| `VERSION` | Version from `package.json` |
| `HELLO_GREETING` | Hello |
| `HELLO_NAME` | Welt |
| `HELLO_COLOR` | `#ff5757` |
| `EARTH_COLOR` | `#57ffd1` |
| `PORT` | 3000 |
| `HOST` | `localhost` in development and `0.0.0.0` in production |
# Demo
This image can be used to demo the following for learning about **container orchestration**.
> [!NOTE]
> These demo routes use `z-pages` covention based on Google's internal practices to indicate that these endpoints are not part of the app's expected functionality.
### Best Practices
| Best Practice | Route | Description |
|:--|:--|:--|
| Health Check | `/healthz` | Health check page with info for debugging. Returns 200. |
| Graceful Shutdown | N/A | See [`app/server.js`](./app/server.js), which responds to `SIGINT` and `SIGTERM` to shutdown database, etc. |
### Problems
| Problem | Route | Description |
|:--|:--|:--|
| Error 500 | `/failz` | Returns 500 response and logs error to stdout. App continunes to run. |
| Crash | `/crashz` | Simulate a crash. App needs to be restarted. |
| Memory Leak | `/slowz` | Simulate a memory leak. App continues to function. |
# Usage
## Pull from Docker Hub
Pull the [julieio/hello](https://hub.docker.com/repository/docker/julieio/hello) public image from Docker Hub and then run it:
```bash
docker pull julieio/hello:latest
docker run -p 3000:3000 julieio/hello:latest
```
Optionally - pass configuration via environment variables:
```bash
docker run -p 3000:3000 -e HELLO_NAME=Julie julieio/hello:latest
```
or build from scratch
```bash
docker build . -t hello-welt
docker run -p 3000:3000 hello-welt
```
## Local Development
To use this image locally, clone this repo, install dependencies and run the app:
```bash
git clone https://github.com/julie-ng/hello-welt
npm install
npm start
```
Then open [http://localhost:3000](http://localhost:3000) in your browser.
### Logging
For local development, we will use [pino-pretty](https://github.com/pinojs/pino-pretty) to format logs with color
```bash
npm install -g pino-pretty
```
We also also use [nodemon](https://nodemon.io/) to automatically restart the app when code changes. Use the `dev` command to put everything together
```bash
npm run dev
```
# References
- [Heroku Blog: Let It Crash: Best Practices for Handling Node.js Errors on Shutdown](https://blog.heroku.com/best-practices-nodejs-errors) by Julián Duque
- [Snyk Blog: 10 best practices to containerize Node.js web applications with Docker](https://snyk.io/blog/10-best-practices-to-containerize-nodejs-web-applications-with-docker/) by
Liran Tal and Yoni Goldberg
# License
MIT