GONGS - Go Nats Generic Streams

A thin wrapper around Nats Jetstream client that uses Go Generics to provide strongly typed NATS streams.

Example Usage

Define the Type that will be published and retrieved from the NATS stream:

type ExampleMsgEventData struct {
	Id          string
	Type        string
	Description string
}

type ExampleMsg struct {
	eventData *ExampleMsgEventData
}

// Mandatory - Implement the `gongs.MsgEvent` interface
func (e *ExampleMsg) GetId(ctx context.Context) string {
	return e.eventData.Id
}

func (e *ExampleMsg) DecodeEventData(b []byte) error {
	d := &ExampleMsgEventData{}
	json.Unmarshal(b, d)
	e.eventData = d
	return nil
}

func (e *ExampleMsg) EncodeEventData(ctx context.Context) []byte {
	b, _ := json.Marshal(e.eventData)
	return b
}

Create a Generic Stream for the above type:

	// create Jetstream for Stream
	cfg := &nats.StreamConfig{
		Name:      "EXAMPLE",
		Subjects:  []string{"example.>"},
		Storage:   nats.MemoryStorage,
		Retention: nats.WorkQueuePolicy,
	}
	js, _ := nc.JetStream()
	js.AddStream(cfg)

	// create Generic Stream
	q := gongs.NewGenericStream[ExampleMsg](js, "example.events", cfg.Name)

Publish event

	ctx := context.Background()
	// Publish an event
	q.Publish(ctx, &ExampleMsg{
		eventData: &ExampleMsgEventData{
			Id:          "abc123",
			Type:        "start",
			Description: "An important task has started",
		},
	})

Read the last event off queue.

	// Read event from NATS
	event, _ := q.GetLastMsg("example")

	fmt.Printf("Id: %s [%s] - %s",
		event.eventData.Id,
		event.eventData.Type,
		event.eventData.Description,
	)

sl1pm4t/gongs

GONGS - Go Nats Generic Streams

Example Usage