Send notifications to Slack

This document explains how to send budget notifications to Slack.

Budgets are typically configured to send email notifications. However, email isn't always the best way to stay up to date on your cloud costs, particularly if your budget is critical and time sensitive. With programmatic notifications, you can forward your budget messages to other mediums, such as Slack.

Before you begin

Before you begin, you must complete the following tasks:

  1. Enable the Cloud Billing API
  2. Create a budget
  3. Set up programmatic budget notifications

Set up a Slack channel and permissions

The first step is to create your Slack workspace and the bot user tokens that are used to call the Slack API. API tokens can be managed at https://api.slack.com/apps. For detailed instructions, see Bot Users on the Slack site.

Configure Slack notifications.

Set up a Cloud Run function

  1. Complete the steps in Create a Cloud Run function. Ensure that the Trigger type is set to the same Pub/Sub topic that your budget will use.

  2. Add the following dependencies:

    Node.js

    Copy the following to your package.json:

    {
  "name": "cloud-functions-billing",
  "private": "true",
  "version": "0.0.1",
  "description": "Examples of integrating Cloud Functions with billing",
  "main": "index.js",
  "engines": {
    "node": ">=16.0.0"
  },
  "scripts": {
    "compute-test": "c8 mocha -p -j 2 test/periodic.test.js --timeout=600000",
    "test": "c8 mocha -p -j 2 test/index.test.js --timeout=5000 --exit"
  },
  "author": "Ace Nassri <anassri@google.com>",
  "license": "Apache-2.0",
  "dependencies": {
    "@google-cloud/billing": "^4.0.0",
    "@google-cloud/compute": "^4.0.0",
    "google-auth-library": "^9.0.0",
    "googleapis": "^143.0.0",
    "slack": "^11.0.1"
  },
  "devDependencies": {
    "@google-cloud/functions-framework": "^3.0.0",
    "c8": "^10.0.0",
    "gaxios": "^6.0.0",
    "mocha": "^10.0.0",
    "promise-retry": "^2.0.0",
    "proxyquire": "^2.1.0",
    "sinon": "^18.0.0",
    "wait-port": "^1.0.4"
  }
}

    Python

    Copy the following to your requirements.txt:

    slackclient==2.9.4
google-api-python-client==2.131.0

  3. Copy the following code into your Cloud Run function to post budget notifications to a Slack chat channel using the Slack API:

    Node.js 

    const slack = require('slack');

// TODO(developer) replace these with your own values
const BOT_ACCESS_TOKEN =
  process.env.BOT_ACCESS_TOKEN || 'xxxx-111111111111-abcdefghidklmnopq';
const CHANNEL = process.env.SLACK_CHANNEL || 'general';

exports.notifySlack = async pubsubEvent => {
  const pubsubAttrs = pubsubEvent.attributes;
  const pubsubData = Buffer.from(pubsubEvent.data, 'base64').toString();
  const budgetNotificationText = `${JSON.stringify(
    pubsubAttrs
  )}, ${pubsubData}`;

  await slack.chat.postMessage({
    token: BOT_ACCESS_TOKEN,
    channel: CHANNEL,
    text: budgetNotificationText,
  });

  return 'Slack notification sent successfully';
};

    Python 

    import base64
import json
import os

import slack
from slack.errors import SlackApiError

# See https://api.slack.com/docs/token-types#bot for more info
BOT_ACCESS_TOKEN = "xxxx-111111111111-abcdefghidklmnopq"
CHANNEL = "C0XXXXXX"

slack_client = slack.WebClient(token=BOT_ACCESS_TOKEN)


def notify_slack(data, context):
    pubsub_message = data

    # For more information, see
    # https://cloud.google.com/billing/docs/how-to/budgets-programmatic-notifications#notification_format
    try:
        notification_attr = json.dumps(pubsub_message["attributes"])
    except KeyError:
        notification_attr = "No attributes passed in"

    try:
        notification_data = base64.b64decode(data["data"]).decode("utf-8")
    except KeyError:
        notification_data = "No data passed in"

    # This is just a quick dump of the budget data (or an empty string)
    # You can modify and format the message to meet your needs
    budget_notification_text = f"{notification_attr}, {notification_data}"

    try:
        slack_client.api_call(
            "chat.postMessage",
            json={"channel": CHANNEL, "text": budget_notification_text},
        )
    except SlackApiError:
        print("Error posting to Slack")

  4. Ensure the following Slack API postMessage parameters are set correctly:

    • Bot User OAuth access token
    • Channel name

Test your function

To ensure your function works as expected, follow the steps in Test a Cloud Run function.

If successful, a message will show up in Slack.

What's next

Review other programmatic notification examples to learn how to do the following: