Quickstart: Receive events using Pub/Sub

This quickstart shows you how to deploy an unauthenticated Cloud Run service that receives events using Pub/Sub.

In this quickstart, you:

  1. Deploy an event receiver service to Cloud Run.

  2. Create an Eventarc trigger.

  3. Publish a message to a Pub/Sub topic to generate an event, and view it in the Cloud Run logs.

Before you begin

Some of the steps in this document might not work correctly if your organization applies constraints to your Google Cloud environment. In that case, you might not be able to complete tasks like creating public IP addresses or service account keys. If you make a request that returns an error about constraints, see how to Develop applications in a constrained Google Cloud environment.

  1. Sign in to your Google Cloud account. If you're new to Google Cloud, create an account to evaluate how our products perform in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.
  2. In the Google Cloud Console, on the project selector page, select or create a Google Cloud project.

    Go to project selector

  3. Make sure that billing is enabled for your Cloud project. Learn how to confirm that billing is enabled for your project.

  4. Enable the Cloud Run, Cloud Logging, Cloud Build, Pub/Sub, Eventarc APIs.

    Enable the APIs

  5. Install and initialize the Cloud SDK.
  6. Update gcloud components:
    gcloud components update
  7. Log in using your account:
    gcloud auth login
  8. Set the configuration variables used in this quickstart:

    gcloud config set project PROJECT_ID
    gcloud config set run/region us-central1
    gcloud config set run/platform managed
    gcloud config set eventarc/location us-central1
    

    Where PROJECT_ID is your Google Cloud project ID.

Deploy an event receiver to Cloud Run

Deploy a Cloud Run service that receives and logs events.

  1. Clone the repository:

    Node.js

    git clone https://github.com/GoogleCloudPlatform/nodejs-docs-samples.git

    Alternatively, you can download the sample as a zip file and extract it.

    Python

    git clone https://github.com/GoogleCloudPlatform/python-docs-samples.git

    Alternatively, you can download the sample as a zip file and extract it.

    Go

    git clone https://github.com/GoogleCloudPlatform/golang-samples.git

    Alternatively, you can download the sample as a zip file and extract it.

    Java

    git clone https://github.com/GoogleCloudPlatform/java-docs-samples.git

    Alternatively, you can download the sample as a zip file and extract it.

    Ruby

    git clone https://github.com/GoogleCloudPlatform/ruby-docs-samples.git

    Alternatively, you can download the sample as a zip file and extract it.

    C#

    git clone https://github.com/GoogleCloudPlatform/dotnet-docs-samples.git

    Alternatively, you can download the sample as a zip file and extract it.

  2. Change to the directory that contains the Cloud Run sample code:

    Node.js

    cd nodejs-docs-samples/eventarc/pubsub/

    Python

    cd python-docs-samples/eventarc/pubsub/

    Go

    cd golang-samples/eventarc/pubsub/

    Java

    cd java-docs-samples/eventarc/pubsub/

    Ruby

    cd ruby-docs-samples/eventarc/pubsub/

    C#

    cd dotnet-docs-samples/eventarc/pubsub/
  3. Build the container and upload it to Cloud Build:

    gcloud builds submit --tag gcr.io/$(gcloud config get-value project)/events-pubsub
    
  4. Deploy the container image to Cloud Run:

    gcloud run deploy helloworld-events-pubsub-quickstart \
        --image gcr.io/$(gcloud config get-value project)/events-pubsub \
        --allow-unauthenticated
    

When you see the service URL, the deployment is complete.

Create an Eventarc trigger

The event trigger sends messages to the event receiver service deployed on Cloud Run when a message is published to the Pub/Sub topic.

  1. Create a trigger to listen for Pub/Sub messages:

    New Pub/Sub topic

    gcloud eventarc triggers create events-pubsub-trigger \
      --destination-run-service=helloworld-events-pubsub-quickstart \
      --destination-run-region=us-central1 \
      --event-filters="type=google.cloud.pubsub.topic.v1.messagePublished"
    

    This creates a new Pub/Sub topic and a trigger for it called events-pubsub-trigger.

    Existing Pub/Sub topic

    gcloud eventarc triggers create events-pubsub-trigger \
      --destination-run-service=helloworld-events-pubsub-quickstart \
      --destination-run-region=us-central1 \
      --event-filters="type=google.cloud.pubsub.topic.v1.messagePublished" \
      --transport-topic=projects/PROJECT_ID/topics/TOPIC_ID
    

    Replace the following:

    • PROJECT_ID is your Google Cloud project ID
    • TOPIC_ID is the ID of the existing Pub/Sub topic.

    This creates a trigger called events-pubsub-trigger for the existing Pub/Sub topic.

  2. Confirm the trigger was successfully created:

    gcloud eventarc triggers list --location=us-central1
    

Send and view events in a Pub/Sub topic

Eventarc events are messages published to a Pub/Sub topic. To send events using a Pub/Sub topic:

  1. Find and set the Pub/Sub topic as an environment variable:

    export RUN_TOPIC=$(gcloud eventarc triggers describe events-pubsub-trigger \
        --format='value(transport.pubsub.topic)')
    
  2. Send a message to the Pub/Sub topic to generate an event:

    gcloud pubsub topics publish $RUN_TOPIC --message "Runner"
    

    The event is sent to the Cloud Run service, which logs the event message.

  3. To view the event message, go to the Cloud Run service logs:

    1. Go to the Google Cloud Console
    2. Click the helloworld-events-pubsub-quickstart service.
    3. Select the Logs tab.

      Logs might take a few moments to appear. If you don't see them immediately, check again after a few moments.

  4. Look for the "Hello Runner!" message.

Congratulations! You have successfully deployed an event receiver service to Cloud Run, created an Eventarc trigger, generated an event from Pub/Sub, and viewed it in the Cloud Run logs.

Clean up

While Cloud Run does not charge when the service is not in use, you might still be charged for storing the container image in Container Registry, Eventarc resources, and for Pub/Sub messages.

You can delete your image, delete the Pub/Sub topic, and delete the Pub/Sub subscription. To delete the Eventarc trigger:

gcloud eventarc triggers delete events-pubsub-trigger

Alternatively, you can delete your Google Cloud project to avoid incurring charges. Deleting your Cloud project stops billing for all the resources used within that project.

  1. In the Cloud Console, go to the Manage resources page.

    Go to Manage resources

  2. In the project list, select the project that you want to delete, and then click Delete.
  3. In the dialog, type the project ID, and then click Shut down to delete the project.

What's next