Chapter 6. Workflow eventing system

To configure a platform-scoped eventing system, you can use the spec.eventing.broker.ref field in the SonataFlowPlatform custom resource (CR) to reference a Knative Eventing broker.

This configuration instructs the OpenShift Serverless Logic Operator to automatically link every workflow deployed in the specified namespace, using the preview or gitops profile, to produce and consume events through the defined broker.

The supporting services deployed in the namespace without a custom eventing configuration are also linked to this broker.

The following example displays how to configure the SonataFlowPlatform CR for a platform-scoped eventing system:

apiVersion: sonataflow.org/v1alpha08
kind: SonataFlowPlatform
metadata:
  name: sonataflow-platform-example
  namespace: <example-namespace>
spec:
  eventing:
    broker:
      ref:
        name: example-broker 1
        namespace: <example-broker-namespace> 2
        apiVersion: eventing.knative.dev/v1
        kind: Broker

A workflow-scoped eventing system configuration allows for detailed customization of the events produced and consumed by a specific workflow. You can use the spec.sink.ref and spec.sources[] fields in the SonataFlow CR to configure outgoing and incoming events.

apiVersion: sonataflow.org/v1alpha08
kind: SonataFlow
metadata:
  name: example-workflow
  namespace: example-workflow-namespace
  annotations:
    sonataflow.org/description: Example Workflow
    sonataflow.org/version: 0.0.1
    sonataflow.org/profile: preview
spec:
  sink:
    ref:
      name: outgoing-example-broker 1
      namespace: outgoing-example-broker-namespace 2
      apiVersion: eventing.knative.dev/v1
      kind: Broker
  flow: 3
    start: ExampleStartState
    events: 4
      - name: outEvent1 5
        source: ''
        kind: produced
        type: out-event-type1 6
    ...

apiVersion: sonataflow.org/v1alpha08
kind: SonataFlow
metadata:
  name: example-workflow
  namespace: example-workflow-namespace
  annotations:
    sonataflow.org/description: Example Workflow
    sonataflow.org/version: 0.0.1
    sonataflow.org/profile: preview
spec:
  sources:
    - eventType: in-event-type1 1
      ref:
        name: incoming-example-broker1 2
        namespace: incoming-example-broker1-namespace 3
        apiVersion: eventing.knative.dev/v1
        kind: Broker
    - eventType: in-event-type2 4
      ref:
        name: incoming-example-broker2 5
        namespace: incoming-example-broker2-namespace 6
        apiVersion: eventing.knative.dev/v1
        kind: Broker
  flow: 7
    start: ExampleStartState
    events: 8
      - name: inEvent1 9
        source: ''
        kind: consumed
        type: in-event-type1 10
      - name: inEvent2 11
        source: ''
        kind: consumed
        type: in-event-type2 12
    ...

In a SonataFlowClusterPlatform setup, workflows are automatically linked to the Broker specified in the associated SonataFlowPlatform CR. This linkage follows the Eventing System configuration precedence rules.

To ensure proper integration, you can configure Broker in the SonataFlowPlatform CR referenced by the SonataFlowClusterPlatform CR.

The following example displays how to configure the SonataFlowClusterPlatform CR and its reference to the SonataFlowPlatform CR:

apiVersion: sonataflow.org/v1alpha08
kind: SonataFlowPlatform
metadata:
  name: global-platform
  namespace: global-namespace
spec:
  eventing:
    broker:
      ref:
        name: global-broker
        namespace: global-namespace
        apiVersion: eventing.knative.dev/v1
        kind: Broker
---
apiVersion: sonataflow.org/v1alpha08
kind: SonataFlowClusterPlatform
metadata:
  name: cluster-platform-example
spec:
  platformRef:
    name: global-platform
    namespace: global-namespace
    ...

The OpenShift Serverless Logic Operator follows a defined order of precedence to determine the eventing system configuration for a workflow.

Eventing system configuration precedence rules are as follows:

The OpenShift Serverless Logic Operator links workflows with the eventing system using Knative Eventing, SinkBindings, and triggers. These objects are created automatically by the OpenShift Serverless Logic Operator and simplify the production and consumption of workflow events.

The following example shows the Knative Eventing objects created for an example-workflow workflow configured with a platform-scoped eventing system:

apiVersion: sonataflow.org/v1alpha08
kind: SonataFlowPlatform
metadata:
  name: sonataflow-platform-example
  namespace: example-namespace
spec:
  eventing:
    broker:
      ref:
        name: example-broker 1
        apiVersion: eventing.knative.dev/v1
        kind: Broker
  services:
    dataIndex: 2
      enabled: true
    jobService: 3
      enabled: true
  ...

The example-broker object is a Kafka class Broker, and its configuration is defined in the kafka-broker-config config map.

The following example displays how to configure a Kafka Knative Broker for use with the SonataFlowPlatform:

apiVersion: eventing.knative.dev/v1
kind: Broker
metadata:
  annotations:
    eventing.knative.dev/broker.class: Kafka 1
  name: example-broker
  namespace: example-namespace
spec:
  config:
    apiVersion: v1
    kind: ConfigMap
    name: kafka-broker-config
    namespace: knative-eventing

The following example displays how the example-workflow is automatically linked to the example-broker in the example-namespace for event production and consumption:

apiVersion: sonataflow.org/v1alpha08
kind: SonataFlow
metadata:
  name: example-workflow
  namespace: example-namespace
  annotations:
    sonataflow.org/description: Example Workflow
    sonataflow.org/version: 0.0.1
    sonataflow.org/profile: preview
spec:
  flow:
    start: ExampleStartState
    events:
      - name: outEvent1
        source: ''
        kind: produced
        type: out-event-type1 1
      - name: inEvent1
        source: ''
        kind: consumed
        type: in-event-type1 2
      - name: inEvent2
        source: ''
        kind: consumed
        type: in-event-type2 3
    states:
      - name: ExampleStartState
    ...

You can list the automatically created SinkBinding named example-workflow-sb by using the following command:

$ oc get sinkbindings -n example-namespace

NAME                   TYPE          RESOURCE                           SINK                    READY
example-workflow-sb    SinkBinding   sinkbindings.sources.knative.dev   broker:example-broker   True

You can use the following command to list the automatically created triggers for event consumption:

$ oc get triggers -n <example-namespace>

NAME                                                              BROKER           SINK                                                     AGE   CONDITIONS   READY   REASON
example-workflow-inevent1-b40c067c-595b-4913-81a4-c8efa980bc11    example-broker   service:example-workflow                                 16m   7 OK / 7     True
example-workflow-inevent2-b40c067c-595b-4913-81a4-c8efa980bc11    example-broker   service:example-workflow                                 16m   7 OK / 7     True