Eventing Overview

Weik.io’s eventing system standardizes event messaging on CloudEvents. NATS JetStream stores the events, and Apache Camel Kamelets move them between systems.

What is eventing?#

Weik.io routes events through a central messaging backbone instead of point-to-point connections. External systems push data in, Weik.io converts it to the CloudEvents standard, stores it in NATS JetStream, and delivers it to subscribers. This follows a standard publish-subscribe model, with CloudEvents enforced throughout to keep events consistent and easier to debug.

Core components#

Events#

Every message moving through the system is a CloudEvent. You always get a predictable envelope with standard attributes, such as type, source, id, and time, wrapped around your actual data.

Event Sources#

Event Sources are where data enters the system. They use Apache Camel Kamelets to connect to external APIs, databases, or message brokers. Once data arrives, the source converts it to a CloudEvent and publishes it to a dedicated NATS JetStream stream.

Configuration example:

apiVersion: weik.io/v1alpha1
kind: EventSource
metadata:
  name: s3-events
spec:
  type: aws-s3-source
  parameters:
    bucketNameOrArn: "my-bucket"
    region: "eu-west-1"

See the Event Sources reference for the available connectors.

Event Channels#

Event Channels deliver data out of the system. They take CloudEvents and use Camel Kamelets to deliver them to external targets.

Configuration example:

apiVersion: weik.io/v1alpha1
kind: EventChannel
metadata:
  name: webhook-channel
spec:
  type: http
  parameters:
    url: "https://example.com/webhook"
    method: "POST"

See Event Channels for the full list of delivery options.

Event Subscriptions#

Sources and channels are independent of each other. Event Subscriptions connect them by routing events from a specific source to a specific channel.

Configuration example:

apiVersion: weik.io/v1alpha1
kind: EventSubscription
metadata:
  name: s3-to-webhook
spec:
  source: s3-events
  channel: webhook-channel

See Event Subscriptions for more details.

Streams#

NATS JetStream stores the events in a durable, ordered log. If a target system goes down, the events wait in the stream until they can be delivered.

Event flow#

Events move through the system in four steps:

1. An Event Source reads data from an external system.
2. It publishes a CloudEvent to a NATS stream.
3. An Event Subscription picks up the event.
4. An Event Channel pushes it to the target system.

Supported patterns#

Publish-subscribe#

You can attach multiple channels to a single source. Each subscription gets its own consumer, so one slow target does not block other systems from receiving the same event.

Event replay#

Because NATS keeps a record, you can replay events from the past. If a downstream system loses data, you can replay the stream from an earlier point to recover it.

Configuration#

You configure these components with YAML. Weik.io supports variable substitution so you do not have to hardcode secrets in YAML files.

Example with variables:

apiVersion: weik.io/v1alpha1
kind: EventSource
metadata:
  name: s3-events
spec:
  type: aws-s3-source
  parameters:
    accessKey: "{{accessKey}}"
    secretKey: "{{secretKey}}"
  variables:
    - accessKey: "{{sys:AWS_ACCESS_KEY}}"
    - secretKey: "{{sys:AWS_SECRET_KEY}}"

See Variables to learn how to manage secrets safely.

Next steps#

• Events: View and manage events
• Streams: Configure event streams
• Event Sources: Capture events from systems
• Event Channels: Deliver events to destinations
• Event Subscriptions: Route events through your system