Cloud Functions and Serverless (Cloud Run)

GCP offers several serverless compute options that let you run code without managing infrastructure. This lesson covers Cloud Functions for event-driven functions and Cloud Run for containerised applications.

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What Is Serverless on GCP?

Serverless means you don't manage servers. GCP handles provisioning, scaling, patching, and availability. You focus on your code and pay only for what you use.

GCP Serverless Compute Options

Service	Unit of Deployment	Use Case
Cloud Functions	A single function	Event-driven, lightweight operations
Cloud Run	A container image	Any HTTP service, APIs, microservices
App Engine	An application	Web applications, full app lifecycle

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Cloud Functions

Cloud Functions is GCP's Functions-as-a-Service (FaaS) offering. Write a single-purpose function, deploy it, and GCP runs it in response to events.

How It Works

1. You write a function in a supported language
2. You configure a trigger (HTTP request, Cloud Storage event, Pub/Sub message, etc.)
3. When the trigger fires, Cloud Functions executes your code
4. The platform scales automatically — from zero to thousands of instances

Supported Runtimes

Runtime	Languages
Node.js	16, 18, 20
Python	3.9, 3.10, 3.11, 3.12
Go	1.20, 1.21, 1.22
Java	11, 17, 21
Ruby	3.0, 3.2
.NET	6, 8
PHP	8.1, 8.2, 8.3

Trigger Types

Trigger	Event
HTTP	An HTTP request
Cloud Storage	Object created, deleted, archived, or metadata updated
Pub/Sub	Message published to a topic
Firestore	Document created, updated, deleted, or written
Cloud Audit Logs	Log entry matching a filter
Cloud Scheduler	Scheduled interval (cron)
Eventarc	Events from 130+ sources

Example: HTTP Function (Python)

import functions_framework

@functions_framework.http
def hello(request):
    name = request.args.get('name', 'World')
    return f'Hello, {name}!'

Deploy:

gcloud functions deploy hello \
  --gen2 \
  --runtime=python312 \
  --region=europe-west2 \
  --trigger-http \
  --allow-unauthenticated

Generations

Feature	1st Gen	2nd Gen
Runtime	Cloud Functions only	Built on Cloud Run
Max timeout	9 minutes	60 minutes
Max instances	1,000	1,000 (configurable)
Concurrency	1 request per instance	Multiple requests per instance
Traffic splitting	No	Yes
Event sources	Limited	130+ via Eventarc

2nd Gen is recommended for all new functions.

Pricing

Component	Rate
Invocations	$0.40 per million
Compute time	Varies by memory/CPU allocated
Networking	Outbound data transfer charges