durable-streams-go

Go implementation of Durable Streams.

Conformance

Tested against conformance tests v0.1.8:

Suite	Tests	Passed	Failed
Server (memorystorage)	195	195	0
Client	177	177	0

Client features: batching, sse, longPoll, streaming, dynamicHeaders

Offset Format

This implementation uses the same offset format as the reference Node.js implementation:

<readSeq>_<byteOffset>

Both components are 16-digit zero-padded integers, e.g., 0000000000000000_0000000000000042. This ensures lexicographic sortability as required by PROTOCOL.md Section 6.

Test Coverage

Package	Coverage
durablestream	90.7%
durablestream/transport	93.1%
durablestream/storage/memorystorage	96.2%
durablestream/internal/protocol	98.1%

Usage

Server

func ExampleHandler() {
	storage := memorystorage.New()
	handler := durablestream.NewHandler(storage, nil)

	mux := http.NewServeMux()
	mux.Handle("/v1/stream/", http.StripPrefix("/v1/stream/", handler))

	log.Println("Listening on :4437")
	log.Fatal(http.ListenAndServe(":4437", mux))
}

Client

func ExampleClient() {
	ctx := context.Background()

	client := durablestream.NewClient("http://localhost:4437/streams", nil)

	_, err := client.Create(ctx, "events", &durablestream.CreateOptions{
		ContentType: "application/json",
	})
	if err != nil {
		log.Fatal(err)
	}

	// Write using Writer
	writer, err := client.Writer(ctx, "events")
	if err != nil {
		log.Fatal(err)
	}

	event := map[string]any{"type": "user.created", "id": 123}
	if err := writer.SendJSON(event, nil); err != nil {
		log.Fatal(err)
	}
	fmt.Println("Appended at offset:", writer.Offset())

	// Read using Reader
	reader := client.Reader("events", durablestream.ZeroOffset)
	defer reader.Close()

	result, err := reader.Read(ctx)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println("Got data:", len(result.Data) > 0)
	fmt.Println("Next offset:", result.NextOffset)
}

Streaming Reader

func ExampleReader() {
	ctx := context.Background()

	client := durablestream.NewClient("http://localhost:4437/streams", nil)

	// Create a reader starting from offset 0
	reader := client.Reader("events", durablestream.ZeroOffset)
	defer reader.Close()

	for msg, err := range reader.Messages(ctx) {
		if err != nil {
			log.Fatal(err)
		}
		// Use msg.String() for text, msg.Bytes() for raw bytes,
		// or msg.Decode(&v) for JSON
		fmt.Println("Received:", msg.String())
	}
}

License

MIT - see LICENSE