README.md

CloudPubSubSource Example

Overview

This sample shows how to configure CloudPubSubSources. The CloudPubSubSource fires a new event each time a message is published on a Cloud Pub/Sub topic. This source sends events using a Push-compatible format.

Prerequisites

1. Install Knative-GCP

2. Create a Service Account for the Data Plane

Deployment

1. Create a GCP PubSub Topic. If you change its name (testing), you also need to update the topic in the CloudPubSubSource file.

   1. If you are in GKE and using Workload Identity, update serviceAccountName with the Kubernetes service account you created in Create a Service Account for the Data Plane, which is bound to the Pub/Sub enabled Google service account.

   2. If you are using standard Kubernetes secrets, but want to use a non-default one, update secret with your own secret.

   3. By default, the Pub/Sub Topic will exist in the same project as your GKE cluster. However, if you are managing multiple projects, then you can specify spec.project, which is the Google Cloud Project that the Topic exists in.

   gcloud pubsub topics create testing --project=your-project-id

2. Create a CloudPubSubSource

   kubectl apply --filename cloudpubsubsource.yaml

3. Create a Service that the CloudPubSubSource will sink into:

   kubectl apply --filename event-display.yaml

Publish

Publish messages to your GCP PubSub topic:

gcloud pubsub topics publish testing --message='{"Hello": "world"}' --topic-project=$PROJECT_ID

Verify

We will verify that the published event was sent by looking at the logs of the service that this CloudPubSubSource sinks to.

1. We need to wait for the downstream pods to get started and receive our event, wait 60 seconds. You can check the status of the downstream pods with:

   kubectl get pods --selector app=event-display

   You should see at least one.

2. Inspect the logs of the service:

   kubectl logs --selector app=event-display -c user-container --tail=200

You should see log lines similar to:

☁️  cloudevents.Event
Validation: valid
Context Attributes,
  specversion: 1.0
  type: google.cloud.pubsub.topic.v1.messagePublished
  source: //pubsub.googleapis.com/projects/test-project/topics/testing
  id: 1314133748793931
  time: 2020-06-30T16:32:57.012Z
  dataschema: https://raw.githubusercontent.com/googleapis/google-cloudevents/master/proto/google/events/cloud/pubsub/v1/data.proto
  datacontenttype: application/json
Extensions,
  knativearrivaltime: 2020-06-30T16:32:58.016175839Z
  knsourcetrigger: link0.13999342310482066
  traceparent: 00-e9ce0f38d85d8333bd1a3334ead78b4d-acd063b2d3e93980-00
Data,
  {
    "subscription": "cre-src_rc3_source-for-knativegcp-test-pubsub-tr_fcdf7716-c4bd-43b9-8ccc-e6e8ff848cd4",
    "message": {
      "messageId": "1314133748793931",
      "data": "eyJIZWxsbyI6ICJ3b3JsZCJ9", // base64 encoded '{"Hello": "world"}'
      "publishTime": "2020-06-30T16:32:57.012Z"
    }
  }

Troubleshooting

You may have issues receiving desired CloudEvent. Please use Authentication Mechanism Troubleshooting to check if it is due to an auth problem.

What's Next

1. For more details on Cloud Pub/Sub formats refer to the Subscriber overview guide.
2. For integrating with Cloud Storage see the Storage example.
3. For integrating with Cloud Scheduler see the Scheduler example.
4. For integrating with Cloud Audit Logs see the Cloud Audit Logs example.
5. For integrating with Cloud Build see the Build example.
6. For more information about CloudEvents, see the HTTP transport bindings documentation.

Cleaning Up

1. Delete the CloudPubSubSource

   kubectl delete -f ./cloudpubsubsource.yaml

2. Delete the Service

   kubectl delete -f ./event-display.yaml