# Kafka Consumer

## Connection

Connect to your Kafka bootstrap broker(s):

```sh
ilagent daemon --kafka_brokers localhost:9092 --kafka_group_id ilagent \
    -e 'events-topic' -r 'heartbeats-topic'
```

| Flag               | Description                                       | Default      |
| ------------------ | ------------------------------------------------- | ------------ |
| `--kafka_brokers`  | Comma-separated broker list (required)            | —            |
| `--kafka_group_id` | Consumer group ID (required)                      | —            |
| `-e`               | Topic for event messages                          | —            |
| `-r`               | Topic for heartbeat messages                      | —            |
| `-p`               | HTTP server port (for health/readiness endpoints) | *(disabled)* |

{% hint style="info" %}
Kafka mode does not start the HTTP server by default. Pass `-p` explicitly if you need `/health` and `/ready` endpoints (e.g. for Kubernetes probes).
{% endhint %}

## Graceful shutdown

The Kafka consumer shuts down gracefully on SIGINT/SIGTERM — in-flight messages are finished processing and offsets are committed before exit. If the HTTP server is running (`-p`), the `/health` endpoint returns 503 during shutdown to allow load balancers or Kubernetes to drain traffic.

## At least once delivery

In Kafka mode, events are **not** buffered in SQLite. Instead, the consumer offset is used to provide at-least-once delivery. If an event cannot be delivered, the offset is not committed and ilagent will exit after 5 seconds.

We recommend running ilagent so it is automatically restarted on exit:

```sh
docker run --restart always ilert/ilagent daemon \
    --kafka_brokers localhost:9092 --kafka_group_id ilagent \
    -e 'events-topic'
```

## Payload format

All message payloads must be JSON. An example event payload using the default field names:

```json
{
  "integrationKey": "il1api123...",
  "eventType": "ALERT",
  "summary": "Hey from Kafka"
}
```

If your payloads use different field names, you can map them with `--map_key_etype`, `--map_key_summary`, `--map_key_alert_key`, and set a fixed integration key with `--event_key`. See [Event Mapping](/developer-docs/client-libraries/ilagent/event-mapping.md) for details.

{% hint style="warning" %}
The `integrationKey` (or `--event_key`) must belong to a [**Kafka** alert source](https://github.com/iLert/docs/blob/master/product-docs/integrations/inbound-integrations/kafka.md) in ilert. Events sent with integration keys from other alert source types will be rejected.
{% endhint %}

An example heartbeat payload:

```json
{
  "integrationKey": "il1hbt123..."
}
```

## Sample command

```sh
ilagent daemon -v -v \
    --kafka_brokers localhost:9092 \
    --kafka_group_id ilagent \
    -e 'events-topic' -r 'heartbeats-topic'
```

See [Event Mapping](/developer-docs/client-libraries/ilagent/event-mapping.md) for mapping custom message fields to ilert event properties.


---

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