Serverless Containers and Functions: Deploying with Cloud Run and Cloud Functions

Big Picture: Serverless on Google Cloud

Cloud Run Fundamentals: Services, Revisions, and Requests

Hands-On Flow: Deploying to Cloud Run from Source and Registry

Traffic Splitting and Revisions in Cloud Run

Cloud Functions Fundamentals: Functions, Triggers, and Runtimes

Deploying Cloud Functions: HTTP and Event Triggers

This step walks through two concrete Cloud Functions deployments with `gcloud`: one HTTP-triggered, one event-triggered via Pub/Sub.

Assume a Node.js function file `index.js` in directory `hello-fn/`:

```js

// index.js

exports.helloHttp = (req, res) => {

const name = req.query.name || 'World';

res.send(`Hello ${name} from Cloud Functions!`);

};

exports.helloPubSub = (event, context) => {

const message = Buffer.from(event.data, 'base64').toString();

console.log(`Received message: ${message}`);

};

```

And a `package.json` that declares dependencies.

1. Deploy an HTTP-triggered function (2nd gen)

```bash

cd hello-fn

Enable APIs if needed

gcloud services enable cloudfunctions.googleapis.com run.googleapis.com eventarc.googleapis.com

Deploy HTTP function

gcloud functions deploy helloHttp \

--gen2 \

--region=REGION \

--runtime=nodejs20 \

--entry-point=helloHttp \

--trigger-http \

--allow-unauthenticated

```

Key flags:

• `--gen2`: Use 2nd gen (exam questions may specify this).
• `--trigger-http`: Creates an HTTPS endpoint.
• `--allow-unauthenticated`: Make it publicly callable.

2. Deploy an event-driven function triggered by Pub/Sub (2nd gen)

```bash

Create a Pub/Sub topic

gcloud pubsub topics create my-topic

Deploy the function with a Pub/Sub trigger

gcloud functions deploy helloPubSub \

--gen2 \

--region=REGION \

--runtime=nodejs20 \

--entry-point=helloPubSub \

--trigger-topic=my-topic

Test by publishing a message

gcloud pubsub topics publish my-topic --message="Exam prep!"

```

Exam angles:

• Recognize `--trigger-http` vs `--trigger-topic` vs storage triggers like `--trigger-bucket`.
• Understand that for event triggers, Cloud Functions integrates with Pub/Sub and other services via Eventarc under the hood.
• Identify when `--allow-unauthenticated` is (or is not) appropriate based on security requirements.

Autoscaling and Configuration: Cloud Run vs Cloud Functions

Thought Exercise: Choosing Cloud Run vs Cloud Functions

Work through these scenarios mentally. For each, decide whether Cloud Run or Cloud Functions is the better fit, and why. Then compare your reasoning to the guidance.

1. Image processing API

• You have a containerized image-processing service that exposes multiple endpoints (`/resize`, `/thumbnail`, `/filter`). It uses a custom C++ library.
• Which compute option? Why?

Guidance: Cloud Run is a better fit because you already have a container and need a custom C++ library. Cloud Functions only supports managed runtimes and is aimed at single-purpose functions, not a multi-endpoint API.

1. Audit log forwarding

• You need to forward Cloud Audit Logs entries to an external SIEM whenever a new log entry matches certain filters.
• Which compute option? Why?

Guidance: Cloud Functions (event-driven) is ideal. You can use a log sink to Pub/Sub and trigger a function on each message. The function is small, single-purpose, and tightly coupled to events.

1. Public JSON API with canary rollouts

• You are building a public JSON REST API and want to do 5% canary rollouts for new versions while keeping 95% on stable. You want simple traffic splitting with minimal infrastructure.
• Which compute option? Why?

Guidance: Cloud Run is ideal because it supports explicit traffic splitting across revisions. You can send 5% of traffic to the new revision and 95% to the old one without extra load balancers.

1. Scheduled daily job

• A job runs once per day to clean up old data in Cloud Storage. It does not need a custom runtime.
• Which compute option? Why?

Guidance: Cloud Functions triggered by Cloud Scheduler (via Pub/Sub or HTTP) is usually simpler and cheaper than running a container on Cloud Run for a tiny daily task.

Quick Check: Cloud Run and Cloud Functions Basics

Answer this question to reinforce key distinctions.

Quick Check: Cloud Functions Triggers and Autoscaling

Test your understanding of Cloud Functions triggers and scaling behavior.

Key Term Review: Cloud Run and Cloud Functions

Use these flashcards to reinforce essential terms and behaviors before moving to practice questions and labs.