# Send Your First Message (/sdks/go/tutorials/first-message)



This is your first hands-on lesson with the Go SDK: create a client, send an event, and receive it. Make sure you have the SDK installed (see the [Go SDK overview](/sdks/go)).

## Create a Client [#create-a-client]

```go title="main.go"
package main

import (
    "context"
    "log"

    "github.com/kubemq-io/kubemq-go/v2"
)

func main() {
    ctx := context.Background()
    client, err := kubemq.NewClient(ctx,
        kubemq.WithAddress("localhost", 50000),
    )
    if err != nil {
        log.Fatal(err)
    }
    defer client.Close()

    log.Println("Connected to KubeMQ")
}
```

## Send Your First Event [#send-your-first-event]

```go title="send_event.go"
err = client.SendEvent(ctx, kubemq.NewEvent().
    SetChannel("notifications").
    SetBody([]byte("hello kubemq")),
)
if err != nil {
    log.Fatal(err)
}
log.Println("Event sent successfully")
```

## Receive Events [#receive-events]

```go title="receive_events.go"
sub, err := client.SubscribeToEvents(ctx, "notifications", "",
    kubemq.WithOnEvent(func(event *kubemq.Event) {
        fmt.Printf("Received: %s\n", event.Body)
    }),
    kubemq.WithOnError(func(err error) {
        log.Println("Error:", err)
    }),
)
if err != nil {
    log.Fatal(err)
}
defer sub.Unsubscribe()
```

## Configuration Options [#configuration-options]

| Option                      | Default                         | Description                        |
| --------------------------- | ------------------------------- | ---------------------------------- |
| `WithAddress(host, port)`   | `localhost:50000`               | KubeMQ server address              |
| `WithClientId(id)`          | Auto-generated UUID             | Unique client identifier           |
| `WithCredentialProvider(p)` | None                            | Authentication credential provider |
| `WithTLS(caCertFile)`       | None (plaintext)                | TLS with CA cert file              |
| `WithReconnectPolicy(p)`    | Infinite retries, 1-30s backoff | Reconnection behavior              |
| `WithConnectionTimeout(d)`  | 10s                             | Initial connection timeout         |
| `WithRetryPolicy(p)`        | 3 retries, 100ms-10s backoff    | Retry for transient failures       |
| `WithLogger(l)`             | None                            | Structured logger                  |
| `WithTracerProvider(tp)`    | None                            | OpenTelemetry tracer               |
| `WithMeterProvider(mp)`     | None                            | OpenTelemetry meter                |

## Error Handling [#error-handling]

All SDK operations return errors as `*kubemq.KubeMQError` with structured error information:

```go
err := client.SendEvent(ctx, event)
if err != nil {
    var ke *kubemq.KubeMQError
    if errors.As(err, &ke) {
        fmt.Printf("Code: %s, Retryable: %v\n", ke.Code, ke.IsRetryable)

        switch ke.Code {
        case kubemq.ErrCodeTimeout:
            // Retry with longer timeout
        case kubemq.ErrCodeAuthentication:
            // Check credentials
        case kubemq.ErrCodeTransient:
            // Automatic retry exhausted
        }
    }
}
```

## Next Steps [#next-steps]

* [Go SDK Reference](/sdks/go/reference) — full API documentation
* [Go SDK Examples](/sdks/go/how-to) — complete examples for all patterns
* [GitHub Repository](https://github.com/kubemq-io/kubemq-go) — source code and issues