nats jetstream cluster

README.md

NATS JetStream Playground

Playground for a Secure, Highly Available NATS Cluster with message persistence (using JetStream).

This repo contains a cluster with 3 nodes and a Go client sending/receiving messages to it.

Pre-requisites

To use this repo, please install:

• Docker
• mkcert (zero-config tool for locally-trusted development certificates)

Installation

Authentication for client-server and server-server (for the cluster) use X509 certificatesn. To install them locally:

make certificates

Run it

Spin up the cluster with:

docker-compose up

Run the client with:

cd client
go run client.go

You should see the following appear in your terminal:

connecting securely to cluster
getting JetStream context
stream not found
creating stream "ORDERS" and subject "ORDERS.received"
publishing an order
attempting to receive order
got order: "one big burger"

You can also use nats-io/nats-tools/nats to issue manual commands to the cluster. If you do so, you may need to change the client publish permissions in config/jetstream.conf.

Clean up

Once you are done testing, remove the CA from your local system trust store:

make cleanup

docker-compose.yaml

version: '3'
services:
  n1:
    container_name: n1
    image: nats:2.9.11-alpine
    #entrypoint: /nats-server
    command: "-js --config /config/jetstream.conf --server_name S1"
    networks:
      - nats
    ports:
      - 4222:4222
    volumes:
      - ./config/server1:/config
      - ./persistent-data/server-n1/:/data/nats-server/jetstream

  n2:
    container_name: n2
    image: nats:2.9.11-alpine
    #entrypoint: /nats-server
    command: "-js --config /config/jetstream.conf --server_name S2"
    networks:
      - nats
    ports:
      - 4223:4222
    volumes:
      - ./config/server2:/config
      - ./persistent-data/server-n2/:/data/nats-server/jetstream

  n3:
    container_name: n3
    image: nats:2.9.11-alpine
    #entrypoint: /nats-server
    command: "-js --config /config/jetstream.conf --server_name S3"
    networks:
      - nats
    ports:
      - 4224:4222
    volumes:
      - ./config/server3:/config
      - ./persistent-data/server-n3/:/data/nats-server/jetstream

networks:
  nats: {}

jetstream.conf

debug: true
trace: true

# Each server can connect to clients on the internal port 4222 
# (mapped to external ports in our docker-compose)
port: 4222

# Persistent JetStream data store
jetstream = {
  # Each server persists messages within the docker container
  # at /data/nats-server (mounted as ./persistent-data/server-n… 
  # in our docker-compose)
  store_dir: "/data/nats-server/"
}

# Cluster formation
cluster = {
  name: "JSC"
  listen: "0.0.0.0:4245"

  # Servers can connect to one another at 
  # the following routes
  routes = [
    "nats-route://n2:4245"
    "nats-route://n3:4245"
  ]

}