Nats Module

NATS is a simple, secure and high performance open source messaging system for cloud native applications, IoT messaging, and microservices architectures.

Install

npm install @testcontainers/nats --save-dev

Examples

Connect:

it("should start, connect and close", async () => {
  const container = await new NatsContainer().start();

  // establish connection
  const nc = await connect(container.getConnectionOptions());
  // close the connection
  await nc.close();
  // check if the close was OK
  const err = await nc.closed();
  expect(err).toBe(undefined);

  await container.stop();
});

Publish and subscribe:

it("should subscribe and receive one published message", async () => {
  const SUBJECT = "HELLO";
  const PAYLOAD = "WORLD";

  const container = await new NatsContainer().start();
  const nc = await connect(container.getConnectionOptions());
  const sc = StringCodec();

  //----------------
  const sub = nc.subscribe(SUBJECT);
  (async () => {
    for await (const m of sub) {
      const actual: string = sc.decode(m.data);
      expect(actual).toEqual(PAYLOAD);
    }
  })().then();

  //----------------
  nc.publish(SUBJECT, sc.encode(PAYLOAD));

  //----------------
  await nc.drain();
  await nc.close();
  const err = await nc.closed();
  expect(err).toBe(undefined);

  await container.stop();
});

Set credentials:

it("should start with alternative username and password ", async () => {
  // set username and password like this
  const container = await new NatsContainer().withPass("1234").withUsername("George").start();

  const nc = await connect(container.getConnectionOptions());
  // close the connection
  await nc.close();
  // check if the close was OK
  const err = await nc.closed();
  expect(err).toBe(undefined);

  await container.stop();
});

Enable JetStream:

it("should start with JetStream ", async () => {
  // enable JetStream
  const container = await new NatsContainer().withJetStream().start();

  const nc = await connect(container.getConnectionOptions());

  // ensure JetStream is enabled, otherwise this will throw an error
  await nc.jetstream().jetstreamManager();

  // close the connection
  await nc.close();
  // check if the close was OK
  const err = await nc.closed();
  expect(err).toBe(undefined);

  await container.stop();
});

it("should fail without JetStream ", async () => {
  const container = await new NatsContainer().start();

  const nc = await connect(container.getConnectionOptions());

  // ensure JetStream is not enabled, as this will throw an error
  await expect(nc.jetstream().jetstreamManager()).rejects.toThrow("503");

  // close the connection
  await nc.close();
  // check if the close was OK
  const err = await nc.closed();
  expect(err).toBe(undefined);

  await container.stop();
});