ARC101

Overview
In a challenge lab you’re given a scenario and a set of tasks. Instead of following step-by-step instructions, you will use the skills learned from the labs in the course to figure out how to complete the tasks on your own! An automated scoring system (shown on this page) will provide feedback on whether you have completed your tasks correctly.
When you take a challenge lab, you will not be taught new Google Cloud concepts. You are expected to extend your learned skills, like changing default values and reading and researching error messages to fix your own mistakes.
To score 100% you must successfully complete all tasks within the time period!
Setup
Before you click the Start Lab button
Read these instructions. Labs are timed and you cannot pause them. The timer, which starts when you click Start Lab, shows how long Google Cloud resources are made available to you.
This hands-on lab lets you do the lab activities in a real cloud environment, not in a simulation or demo environment. It does so by giving you new, temporary credentials you use to sign in and access Google Cloud for the duration of the lab.
To complete this lab, you need:
- Access to a standard internet browser (Chrome browser recommended).
Note: Use an Incognito (recommended) or private browser window to run this lab. This prevents conflicts between your personal account and the student account, which may cause extra charges incurred to your personal account.
- Time to complete the lab—remember, once you start, you cannot pause a lab.
Note: Use only the student account for this lab. If you use a different Google Cloud account, you may incur charges to that account.
Challenge scenario
You are just starting your junior cloud engineer role. So far you have been helping teams create and manage Google Cloud resources.
You are expected to have the skills and knowledge for these tasks.
Your challenge
You are asked to help a newly formed development team with some of their initial work on a new project around storing and organizing travel photographs, called Travel. You have been asked to assist the Travel team with initial configuration for their application development environment.
You need to:
- Create a Cloud Storage bucket and share with a second user.
- Create a Pub/Sub topic for the Cloud Run Function to send messages.
- Create a Cloud Run Function that executes every time a new object is created in the Cloud Storage bucket.
- Create an alerting policy to send a notification email about the number of active Cloud Run Function instances.
Some standards you should follow:
- Create all resources in the region unless otherwise directed.
- Use the project VPCs.
- Naming is normally team-resource, e.g. an instance could be named kraken-webserver1
- Allocate cost effective resource sizes. Projects are monitored and excessive resource use will result in the containing project's termination (and possibly yours), so beware. This is the guidance the monitoring team is willing to share; unless directed, use f1-micro for small Linux VMs and e2-medium for Windows or other applications such as Kubernetes nodes.
Each task is described in detail below, good luck!
Task 1. Create a bucket
-
Create a bucket named in region for the storage of the photographs.
-
Grant Storage Object Viewer to on the project containing this new bucket.
Click Check my progress to verify the objective.
Create a bucket called and grant access to .
Task 2. Create a Pub/Sub topic
- Create a Pub/Sub topic called for the Cloud Run Function to send messages.
Click Check my progress to verify the objective.
Create a Pub/Sub topic called .
Task 3. Create the thumbnail Cloud Run Function
-
Create a Cloud Run Function (2nd generation) called (using Node.js 22
) that executes every time an object is created in the bucket you created in task 1.
-
Make sure you set the Entry point (Function to execute) to thumbnail
and Trigger to Cloud Storage
.
-
In line 15 of index.js
replace the text REPLACE_WITH_YOUR_TOPIC ID with the you created in task 2.
index.js:
/* globals exports, require */
//jshint strict: false
//jshint esversion: 6
"use strict";
const crc32 = require("fast-crc32c");
const { Storage } = require('@google-cloud/storage');
const gcs = new Storage();
const { PubSub } = require('@google-cloud/pubsub');
const imagemagick = require("imagemagick-stream");
exports.thumbnail = (event, context) => {
const fileName = event.name;
const bucketName = event.bucket;
const size = "64x64"
const bucket = gcs.bucket(bucketName);
const topicName = "REPLACE_WITH_YOUR_TOPIC ID";
const pubsub = new PubSub();
if ( fileName.search("64x64_thumbnail") == -1 ){
// doesn't have a thumbnail, get the filename extension
var filename_split = fileName.split('.');
var filename_ext = filename_split[filename_split.length - 1];
var filename_without_ext = fileName.substring(0, fileName.length - filename_ext.length );
if (filename_ext.toLowerCase() == 'png' || filename_ext.toLowerCase() == 'jpg'){
// only support png and jpg at this point
console.log(`Processing Original: gs://${bucketName}/${fileName}`);
const gcsObject = bucket.file(fileName);
let newFilename = filename_without_ext + size + '_thumbnail.' + filename_ext;
let gcsNewObject = bucket.file(newFilename);
let srcStream = gcsObject.createReadStream();
let dstStream = gcsNewObject.createWriteStream();
let resize = imagemagick().resize(size).quality(90);
srcStream.pipe(resize).pipe(dstStream);
return new Promise((resolve, reject) => {
dstStream
.on("error", (err) => {
console.log(`Error: ${err}`);
reject(err);
})
.on("finish", () => {
console.log(`Success: ${fileName} → ${newFilename}`);
// set the content-type
gcsNewObject.setMetadata(
{
contentType: 'image/'+ filename_ext.toLowerCase()
}, function(err, apiResponse) {});
pubsub
.topic(topicName)
.publisher()
.publish(Buffer.from(newFilename))
.then(messageId => {
console.log(`Message ${messageId} published.`);
})
.catch(err => {
console.error('ERROR:', err);
});
});
});
}
else {
console.log(`gs://${bucketName}/${fileName} is not an image I can handle`);
}
}
else {
console.log(`gs://${bucketName}/${fileName} already has a thumbnail`);
}
};
package.json:
{
"name": "thumbnails",
"version": "1.0.0",
"description": "Create Thumbnail of uploaded image",
"scripts": {
"start": "node index.js"
},
"dependencies": {
"@google-cloud/pubsub": "^2.0.0",
"@google-cloud/storage": "^5.0.0",
"fast-crc32c": "1.0.4",
"imagemagick-stream": "4.1.1"
},
"devDependencies": {},
"engines": {
"node": ">=4.3.2"
}
}
Note:
You must upload one JPG or PNG image into the bucket to verify the thumbnail was created (after creating the function successfully). Use this image https://storage.googleapis.com/cloud-training/arc101/travel.jpg
; download the image to your machine and then upload that file to your bucket.
You will see a thumbnail image appear shortly afterwards (use REFRESH on the bucket details page).
After you upload the image file, you can click to check your progress below. You do not need to wait for the thumbnail image to be created.
Note: If the function deployed successfully and you do not see the thumbnail image in the bucket, you can check that the Triggers tab displays the trigger information that you previously provided for the function, which may not have saved correctly if you previously encountered errors.
If you do not see the Cloud Storage trigger in the Triggers tab of the function, you can recreate the trigger (see the documentation page titled Create a trigger for services), and then upload a new file again to test again (refresh the page after adding a new file).
Click Check my progress to verify the objective.
Verify that the Cloud Run Function works.
Task 4. Create an alerting policy
-
Create an alerting policy named Active Cloud Run Function Instances
that notifies your personal email account when the number of active Cloud Run Function instances is greater than zero (0
).
-
For the metric, be sure to select Cloud Function > Function > Active Instances.
Click Check my progress to verify the objective.
Verify that a Cloud Run Function alert has been created.
Congratulations!

Earn your next skill badge
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Manual Last Updated March 10, 2025
Lab Last Tested March 10, 2025
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