# Cancel Subscription (/sdks/go/how-to/events/cancel-subscription)



## Overview [#overview]

A live Events subscription holds a client-side goroutine and its underlying gRPC stream open indefinitely, so a long-running service needs an explicit way to tear one down without closing the whole client connection — for example when a feature flag disables a channel, a worker is draining before shutdown, or a subscription needs to be re-created with different options. Calling `Unsubscribe()` on the returned handle stops delivery cleanly and frees those resources on both sides.

`SubscribeToEvents` returns a `*Subscription` handle rather than blocking, so the handler keeps running in the background until you cancel it. `Unsubscribe()` sends an unsubscribe request to the broker and terminates the stream goroutine; `IsDone()` gives you a synchronous check you can poll to confirm the teardown actually completed, which matters in tests and graceful-shutdown paths.

**Gotchas:** `Unsubscribe()` only affects this one handle — a consumer group with multiple subscribers keeps delivering to the others. Events already in flight when you call it may still land in the handler; there's a brief window where the server hasn't yet processed the unsubscribe. And because Events are fire-and-forget, anything published after cancellation is simply dropped for this subscriber — there's no queue to catch up from later.

## Prerequisites [#prerequisites]

* KubeMQ server running on `localhost:50000`
* Go SDK installed (`go get github.com/kubemq-io/kubemq-go/v2`)

## Code [#code]

```go title="main.go"
// Example: events/cancel-subscription
//
// Demonstrates how to cancel (unsubscribe from) an event subscription.
// After cancellation, no more events are delivered to the handler.
//
// Channel: go-events.cancel-subscription
// Client ID: go-events-cancel-subscription-client
//
// Run with a KubeMQ server on localhost:50000
// (see https://docs.kubemq.io/deploy).
package main

import (
	"context"
	"fmt"
	"log"
	"time"

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

func main() {
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	client, err := kubemq.NewClient(ctx,
		kubemq.WithAddress("localhost", 50000),
		kubemq.WithClientId("go-events-cancel-subscription-client"),
	)
	if err != nil {
		log.Fatal(err)
	}
	defer client.Close()

	channel := "go-events.cancel-subscription"
	received := make(chan struct{})

	// Create a subscription.
	sub, err := client.SubscribeToEvents(ctx, channel, "",
		kubemq.WithOnEvent(func(event *kubemq.Event) {
			fmt.Printf("Received: body=%s\n", event.Body)
			close(received)
		}),
		kubemq.WithOnError(func(err error) {
			log.Println("Subscription error:", err)
		}),
	)
	if err != nil {
		log.Fatal(err)
	}

	// Allow time for subscription to register on server
	time.Sleep(1 * time.Second)

	// Send an event and wait for it.
	err = client.SendEvent(ctx, kubemq.NewEvent().
		SetChannel(channel).
		SetBody([]byte("before cancel")).
		SetMetadata("test"))
	if err != nil {
		log.Fatal(err)
	}

	select {
	case <-received:
		fmt.Println("Event received before cancellation")
	case <-ctx.Done():
		log.Fatal("Timed out")
	}

	// Cancel the subscription. After this, no more events are delivered.
	sub.Unsubscribe()
	fmt.Println("Subscription cancelled")

	// Check that the subscription is done.
	if sub.IsDone() {
		fmt.Println("Subscription confirmed done")
	}
}

```

## How It Works [#how-it-works]

1. `SubscribeToEvents` returns a `*Subscription` handle that represents the live gRPC stream.
2. After one event is received and acknowledged via the `received` channel, `sub.Unsubscribe()` sends an unsubscribe request to the broker and terminates the stream goroutine.
3. `sub.IsDone()` is a synchronous check that returns `true` once the stream has fully closed — useful to confirm teardown in tests or cleanup logic.
4. Any events published to `go-events.cancel-subscription` after `Unsubscribe()` returns will not be delivered to this handler.

## Related [#related]

* [Pattern overview](/learn/events/getting-started)
* [Go SDK Reference](/sdks/go/reference)
* [Basic Pub/Sub](/sdks/go/tutorials/basic-pubsub)
* [Consumer Group](/sdks/go/how-to/events/consumer-group)