apiserversource-yaml.adoc

Creating an API server source by using YAML files

Creating Knative resources by using YAML files uses a declarative API, which enables you to describe event sources declaratively and in a reproducible manner. To create an API server source by using YAML, you must create a YAML file that defines an ApiServerSource object, then apply it by using the oc apply command.

Prerequisites

• The {ServerlessOperatorName} and Knative Eventing are installed on the cluster.

• You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in {product-title}.

• You have created the default broker in the same namespace as the one defined in the API server source YAML file.

• Install the OpenShift CLI (oc).

Procedure

snippets/serverless-service-account-apiserversource.adoc

1. Create an API server source as a YAML file:

   apiVersion: sources.knative.dev/v1alpha1
   kind: ApiServerSource
   metadata:
     name: testevents
   spec:
     serviceAccountName: events-sa
     mode: Resource
     resources:
       - apiVersion: v1
         kind: Event
     sink:
       ref:
         apiVersion: eventing.knative.dev/v1
         kind: Broker
         name: default

2. Apply the ApiServerSource YAML file:

   $ oc apply -f <filename>

3. To check that the API server source is set up correctly, create a Knative service as a YAML file that dumps incoming messages to its log:

   apiVersion: serving.knative.dev/v1
   kind: Service
   metadata:
     name: event-display
     namespace: default
   spec:
     template:
       spec:
         containers:
           - image: quay.io/openshift-knative/knative-eventing-sources-event-display:latest

4. Apply the Service YAML file:

   $ oc apply -f <filename>

5. Create a Trigger object as a YAML file that filters events from the default broker to the service created in the previous step:

   apiVersion: eventing.knative.dev/v1
   kind: Trigger
   metadata:
     name: event-display-trigger
     namespace: default
   spec:
     broker: default
     subscriber:
       ref:
         apiVersion: serving.knative.dev/v1
         kind: Service
         name: event-display

6. Apply the Trigger YAML file:

   $ oc apply -f <filename>

7. Create events by launching a pod in the default namespace:

   $ oc create deployment hello-node --image=quay.io/openshift-knative/knative-eventing-sources-event-display

8. Check that the controller is mapped correctly, by entering the following command and inspecting the output:

   $ oc get apiserversource.sources.knative.dev testevents -o yaml

   Example output

   apiVersion: sources.knative.dev/v1alpha1
   kind: ApiServerSource
   metadata:
     annotations:
     creationTimestamp: "2020-04-07T17:24:54Z"
     generation: 1
     name: testevents
     namespace: default
     resourceVersion: "62868"
     selfLink: /apis/sources.knative.dev/v1alpha1/namespaces/default/apiserversources/testevents2
     uid: 1603d863-bb06-4d1c-b371-f580b4db99fa
   spec:
     mode: Resource
     resources:
     - apiVersion: v1
       controller: false
       controllerSelector:
         apiVersion: ""
         kind: ""
         name: ""
         uid: ""
       kind: Event
       labelSelector: {}
     serviceAccountName: events-sa
     sink:
       ref:
         apiVersion: eventing.knative.dev/v1
         kind: Broker
         name: default

Verification

To verify that the Kubernetes events were sent to Knative, you can look at the message dumper function logs.

1. Get the pods by entering the following command:

   $ oc get pods

2. View the message dumper function logs for the pods by entering the following command:

   $ oc logs $(oc get pod -o name | grep event-display) -c user-container

   Example output

   ☁️  cloudevents.Event
   Validation: valid
   Context Attributes,
     specversion: 1.0
     type: dev.knative.apiserver.resource.update
     datacontenttype: application/json
     ...
   Data,
     {
       "apiVersion": "v1",
       "involvedObject": {
         "apiVersion": "v1",
         "fieldPath": "spec.containers{hello-node}",
         "kind": "Pod",
         "name": "hello-node",
         "namespace": "default",
          .....
       },
       "kind": "Event",
       "message": "Started container",
       "metadata": {
         "name": "hello-node.159d7608e3a3572c",
         "namespace": "default",
         ....
       },
       "reason": "Started",
       ...
     }

Deleting the API server source

1. Delete the trigger:

   $ oc delete -f trigger.yaml

2. Delete the event source:

   $ oc delete -f k8s-events.yaml

3. Delete the service account, cluster role, and cluster binding:

   $ oc delete -f authentication.yaml