PingSource example

This example shows how to configure PingSource as an event source for functions.

Before you begin

  1. Set up Knative Serving.
  2. Set up Knative Eventing.

Create a Knative Service

To verify that PingSource is working, create a simple Knative Service that dumps incoming messages to its log.

Use following command to create the service from STDIN:

cat <<EOF | kubectl create -f -
apiVersion: serving.knative.dev/v1
kind: Service
metadata:
  name: event-display
spec:
  template:
    spec:
      containers:
        - image: gcr.io/knative-releases/knative.dev/eventing-contrib/cmd/event_display
EOF

Use following command to create the service from the service.yaml file:

kubectl apply --filename service.yaml

Create a PingSource

For each set of ping events that you want to request, create an Event Source in the same namespace as the destination.

Use following command to create the event source from STDIN:

cat <<EOF | kubectl create -f -
apiVersion: sources.knative.dev/v1alpha2
kind: PingSource
metadata:
  name: test-ping-source
spec:
  schedule: "*/2 * * * *"
  jsonData: '{"message": "Hello world!"}'
  sink:
    ref:
      apiVersion: serving.knative.dev/v1
      kind: Service
      name: event-display
EOF

Use following command to create the event source from the ping-source.yaml file:

kubectl apply --filename ping-source.yaml

Verify

Verify that the message was sent to the Knative eventing system by looking at message dumper logs.

Use following command to view the logs of the event-display service:

kubectl logs -l serving.knative.dev/service=event-display -c user-container --since=10m

You can also use kail instead of kubectl logs to tail the logs of the subscriber.

kail -l serving.knative.dev/service=event-display -c user-container --since=10m

You should see log lines showing the request headers and body from the source:

☁️  cloudevents.Event
Validation: valid
Context Attributes,
  specversion: 1.0
  type: dev.knative.sources.ping
  source: /apis/v1/namespaces/default/pingsources/test-ping-source
  id: d8e761eb-30c7-49a3-a421-cd5895239f2d
  time: 2019-12-04T14:24:00.000702251Z
  datacontenttype: application/json
Data,
  {
    "message": "Hello world!"
  }

Cleanup

You can delete the PingSource instance by entering the following command:

kubectl delete pingsources.sources.knative.dev test-ping-source

kubectl delete --filename ping-source.yaml

Similarly, you can delete the Service instance via:

kubectl delete service.serving.knative.dev event-display

kubectl delete --filename service.yaml