PingSource

version

A PingSource produces events with a fixed payload on a specified cron schedule.

Installation

The PingSource source type is enabled by default when you install Knative Eventing.

Example

This example shows how to send an event every second to a Event Display Service.

Creating a namespace

Create a new namespace called pingsource-example by entering the following command:

  1. kubectl create namespace pingsource-example

Creating the Event Display Service

In this step, you create one event consumer, event-display to verify that PingSource is properly working.

To deploy the event-display consumer to your cluster, run the following command:

  1. kubectl -n pingsource-example apply -f - << EOF
  2. apiVersion: apps/v1
  3. kind: Deployment
  4. metadata:
  5.   name: event-display
  6. spec:
  7.   replicas: 1
  8.   selector:
  9.     matchLabels: &labels
  10.       app: event-display
  11.   template:
  12.     metadata:
  13.       labels: *labels
  14.     spec:
  15.       containers:
  16.         - name: event-display
  17.           image: gcr.io/knative-releases/knative.dev/eventing-contrib/cmd/event_display
  19. ---
  21. kind: Service
  22. apiVersion: v1
  23. metadata:
  24.   name: event-display
  25. spec:
  26.   selector:
  27.     app: event-display
  28.   ports:
  29.   - protocol: TCP
  30.     port: 80
  31.     targetPort: 8080
  32. EOF

Creating the PingSource

You can now create the PingSource sending an event containing {"message": "Hello world!"} every second.

  1. kubectl create -n pingsource-example -f - <<EOF
  2. apiVersion: sources.knative.dev/v1beta1
  3. kind: PingSource
  4. metadata:
  5.   name: test-ping-source
  6. spec:
  7.   schedule: "*/1 * * * *"
  8.   jsonData: '{"message": "Hello world!"}'
  9.   sink:
  10.     ref:
  11.       apiVersion: v1
  12.       kind: Service
  13.       name: event-display
  14. EOF
  1. kn source ping create test-ping-source \
  2.   --namespace pingsource-example
  3.   --schedule "*/1 * * * *" \
  4.   --data '{"message": "Hello world!"}' \
  5.   --sink http://event-display.svc.cluster.local

Verify

View the logs for the event-display event consumer by entering the following command:

  1. kubectl -n pingsource-example logs -l app=event-display --tail=100

This returns the Attributes and Data of the events that the PingSource sent to the event-display Service:

  1. ☁️  cloudevents.Event
  2. Validation: valid
  3. Context Attributes,
  4.   specversion: 1.0
  5.   type: dev.knative.sources.ping
  6.   source: /apis/v1/namespaces/default/pingsources/test-ping-source
  7.   id: d8e761eb-30c7-49a3-a421-cd5895239f2d
  8.   time: 2019-12-04T14:24:00.000702251Z
  9.   datacontenttype: application/json
  10. Data,
  11.   {
  12.     "message": "Hello world!"
  13.   }

Cleanup

Delete the pingsource-example namespace and all of its resources from your cluster by entering the following command:

  1. kubectl delete namespace pingsource-example

Reference Documentation

See the PingSource specification.

Contact

For any inquiries about this source, please reach out on to the Knative users group.