Listen to your Pub/Sub notifications

Example reference architecture

This document explains how to listen to your programmatic budget notifications by subscribing to your Pub/Sub topic with Cloud Run function triggers. Without a subscriber, Pub/Sub drops published messages and you can't retrieve them later. In this document, you'll learn how to complete the following tasks:

1. Create a Cloud Run function that listens to notifications.
2. View Cloud Run function events.
3. Test a Cloud Run function.

Before you begin

Before you begin, you must complete the following tasks:

1. Create a budget
2. Set up programmatic notifications

Create a Cloud Run function

To create a Cloud Run function, complete the following steps:

1. In the Google Cloud console, go to the Cloud Run functionspage.

   Go to Cloud Run functions

2. Click CREATE SERVICE.

3. Select Use an inline editor to create a function.

4. Enter a Service namethat's meaningful to your budget notification.

5. Select the region where your Cloud Run functions will run. You can't edit this setting after you deploy your function.

6. Click Add triggerand select Cloud Pub/Sub.

7. If prompted, enable any required APIs.

8. In the Eventarc triggerpanel, complete the following steps:

   1. Enter a Trigger name.
   2. Set Trigger typeto Google sources.
   3. Set Event providerto Cloud Pub/Sub.
   4. Select the Cloud Pub/Sub topicthat you configured on your budget.
   5. Select a Region.
   6. Click Save trigger.

9. Edit the Identity-Aware Proxy, Billing, Service scaling, Ingress, and Container(s), Volume, Networking, Securitysettings as needed, then click Create.

10. Write code using the inline editor or upload a file that tells your function how to handle notifications.

    See the following examples for code samples:

    • Send notifications to Slack
    • Control resource usage with notifications
    • Disable billing usage with notifications

    For details about the notifications your code will receive, see Notification format .

11. Set Function entry pointto the correct function to execute:

12. Click DEPLOY.

View Cloud Run function events

After you deploy the Cloud Run function, click LOGSto view the logs from your function invocations.

Test a Cloud Run function

As notifications are sent to Pub/Sub, subscribers receive the messages. To test a sample notification and ensure that your function is working as expected, publish a message in Pub/Sub with the following object as the message body:

 {
    "budgetDisplayName": "name-of-budget",
    "alertThresholdExceeded": 1.0,
    "costAmount": 100.01,
    "costIntervalStart": "2019-01-01T00:00:00Z",
    "budgetAmount": 100.00,
    "budgetAmountType": "SPECIFIED_AMOUNT",
    "currencyCode": "USD"
} 

You can also add message attributes such as the billing account ID. For more information, see Notification format .

What's next

To learn more about how you can use programmatic notifications, review the following examples of programmatic cost control responses:

• Send notifications to Slack
• Control resource usage with notifications
• Disable billing usage with notifications