Chapter 3. Connecting to Knative with Kamelets

Set up Knative:

Create kamelet bindings:

In an editor of your choice, create a YAML file with the following basic structure:

apiVersion: camel.apache.org/v1alpha1
kind: KameletBinding
metadata:
  name:
spec:
  source:
  sink:

Add a name for the kamelet binding. For this example, the name is coffees-to-knative because the binding connects the coffee-source kamelet to a Knative destination.

apiVersion: camel.apache.org/v1alpha1
kind: KameletBinding
metadata:
  name: coffees-to-knative
spec:
  source:
  sink:

For the kamelet binding’s source, specify a data source kamelet (for example, the coffee-source kamelet produces events that contain data about coffee) and configure any parameters for the kamelet.

apiVersion: camel.apache.org/v1alpha1
kind: KameletBinding
metadata:
  name: coffees-to-knative
spec:
  source:
    ref:
      kind: Kamelet
      apiVersion: camel.apache.org/v1alpha1
      name: coffee-source
    properties:
      period: 5000
  sink:

For the kamelet binding’s sink specify the Knative channel or broker and the required parameters.

This example specifies a Knative channel as the sink:

apiVersion: camel.apache.org/v1alpha1
kind: KameletBinding
metadata:
  name: coffees-to-knative
spec:
  source:
    ref:
      kind: Kamelet
      apiVersion: camel.apache.org/v1alpha1
      name: coffee-source
    properties:
      period: 5000
  sink:
    ref:
      apiVersion: messaging.knative.dev/v1
      kind: InMemoryChannel
      name: mychannel

This example specifies a Knative broker as the sink:

apiVersion: camel.apache.org/v1alpha1
kind: KameletBinding
metadata:
  name: coffees-to-knative
spec:
  source:
    ref:
      kind: Kamelet
      apiVersion: camel.apache.org/v1alpha1
      name: coffee-source
    properties:
      period: 5000
  sink:
      ref:
        kind: Broker
        apiVersion: eventing.knative.dev/v1
        name: default
      properties:
        type: coffee

Add the kamelet binding as a resource to your OpenShift namespace:

oc apply -f <kamelet binding filename>

For example:

oc apply -f coffees-to-knative.yaml

The Camel K operator generates and runs a Camel K integration by using the KameletBinding resource. It might take a few minutes to build.

To see the status of the KameletBinding:

oc get kameletbindings

To see the status of their integrations:

oc get integrations

To view the integration’s log:

kamel logs <integration> -n <project>

For example:

kamel logs coffees-to-knative -n my-camel-knative

The result is similar to the following output:

...
[1] INFO  [io.quarkus] (main) camel-k-integration 1.4.0 on JVM (powered by Quarkus 1.13.0.Final) started in 2.790s.

In an editor of your choice, create a YAML file with the following basic structure:

apiVersion: camel.apache.org/v1alpha1
kind: KameletBinding
metadata:
  name:
spec:
  source:
  sink:

Add a name for the kamelet binding. For this example, the name is knative-to-log because the binding connects the Knative destination to the log-sink kamelet.

apiVersion: camel.apache.org/v1alpha1
kind: KameletBinding
metadata:
  name: knative-to-log
spec:
  source:
  sink:

For the kamelet binding’s source, specify the Knative channel or broker and the required parameters.

This example specifies a Knative channel as the source:

apiVersion: camel.apache.org/v1alpha1
kind: KameletBinding
metadata:
  name: knative-to-log
spec:
  source:
    ref:
            apiVersion: messaging.knative.dev/v1
            kind: InMemoryChannel
            name: mychannel
  sink:

This example specifies a Knative broker as the source:

apiVersion: camel.apache.org/v1alpha1
kind: KameletBinding
metadata:
  name: knative-to-log
spec:
  source:
    ref:
          kind: Broker
          apiVersion: eventing.knative.dev/v1
          name: default
         properties:
         type: coffee
sink:

For the kamelet binding’s sink, specify the data consumer kamelet (for example, the log-sink kamelet) and configure any parameters for the kamelet, for example:

apiVersion: camel.apache.org/v1alpha1
kind: KameletBinding
metadata:
  name: knative-to-log
spec:
  source:
    ref:
            apiVersion: messaging.knative.dev/v1
            kind: InMemoryChannel
            name: mychannel
  sink:
    ref:
      apiVersion: camel.apache.org/v1alpha1
      kind: Kamelet
      name: log-sink

Add the kamelet binding as a resource to your OpenShift namespace: oc apply -f <kamelet binding filename>

For example:

oc apply -f knative-to-log.yaml

The Camel K operator generates and runs a Camel K integration by using the KameletBinding resource. It might take a few minutes to build.

To see the status of the KameletBinding:

oc get kameletbindings

To see the status of the integration:

oc get integrations

To view the integration’s log:

kamel logs <integration> -n <project>

For example:

kamel logs knative-to-log -n my-camel-knative

In the output, you should see coffee events, for example:

[1] 2021-07-23 13:06:38,111 INFO [sink] (vert.x-worker-thread-1) {"id":254,"uid":"8e180ef7-8924-4fc7-ab81-d6058618cc42","blend_name":"Good-morning Star","origin":"Santander, Colombia","variety":"Kaffa","notes":"delicate, creamy, lemongrass, granola, soil","intensifier":"sharp"}
[1] 2021-07-23 13:06:43,273 INFO [sink] (vert.x-worker-thread-2) {"id":8169,"uid":"3733c3a5-4ad9-43a3-9acc-d4cd43de6f3d","blend_name":"Caf? Java","origin":"Nayarit, Mexico","variety":"Red Bourbon","notes":"unbalanced, full, granola, bittersweet chocolate, nougat","intensifier":"delicate"}

To stop a running integration, delete the associated kamelet binding resource:

oc delete kameletbindings/<kameletbinding-name>

For example:

oc delete kameletbindings/knative-to-log