Demo NPM package release Slack notification

This is a sample application developed for an article written for Confluent's blog. It is not intended to be production-ready, but rather to serve as a basic example of how to use KafkaJS.

This application sets up a server that receives NPM webhook events on package publishing and publishes those messages to Kafka. A consumer then consumes those messages and posts them to a Slack channel.

Getting started

This application requires a reasonably recent version of Node.js (tested on v14). In order to run a local Kafka cluster, Docker is also required.

# Install dependencies
$ npm install

# Start docker containers
$ docker-compose up -d

# Run server and consumer
$ npm start

# If you prefer to run the server and consumer separately
$ npm run start:server
$ npm run start:consumer

Configuration

Configuration is done by setting environment variables:

HOOK_SECRET - Secret used when registering the hook with NPM REQUIRED
SLACK_WEBHOOK_URL - Slack incoming webhook URL to post messages to REQUIRED
TOPIC - The topic to produce to and consume from (default: npm-package-published)
PORT - Port for the HTTP server to listen on (default: 3000)
BOOTSTRAP_BROKER - Initial broker to connect to (default: localhost:9092)
KAFKA_SSL - TLS SecureContext options. Can be set to true to use TLS with default configuration, else a JSON object that gets passed to JSON.parse. false will connect without encryption (default: false)
KAFKA_USERNAME & KAFKA_PASSWORD - SASL credentials. Will connect without authentication if left empty (default: undefined)

Creating a topic

When using the provided docker-compose.yml file, the topic will be created automatically when producing the first message. If not using topic auto-creation, the script in bin/create-topic can be used to create the topic ahead of time:

# Create the topic 'npm-package-published' with 3 partitions
$ ./bin/create-topic "npm-package-published" 3

Sending a test message

To see that the application is working, start the server and consumer and then send a test message:

$ ./bin/send-event
send-event <url> <secret> ./path/to/payload.json

$ ./bin/send-event http://localhost:3000/hook "very-secret-string" ./fixtures/payload.json
"OK"

Registering hook with NPM

npm has the ability to add hooks directly in the CLI. In this example, I'm using ngrok to establish a tunnel to expose my IP on the public internet.