GCP for DevOps — Cloud Functions

Cloud Functions

Cloud Functions (Gen 2) is Google Cloud’s serverless Functions-as-a-Service (FaaS) platform. Write a function, deploy it, and GCP handles scaling, patching, and infrastructure. Gen 2 is built on Cloud Run.

Gen 1 vs Gen 2

Feature	Gen 1	Gen 2
Runtime	Custom	Built on Cloud Run
Concurrency	1 request per instance	Up to 1000 per instance
Timeout	9 minutes	60 minutes
Max memory	8 GB	32 GB
Traffic splitting	No	Yes
Eventarc triggers	No	Yes
Min instances	Yes	Yes

Always use Gen 2 for new functions.

HTTP Function (Python)

# main.py
import functions_framework

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

# requirements.txt
functions-framework==3.*

# Deploy HTTP function
$ gcloud functions deploy hello \
    --gen2 \
    --runtime=python312 \
    --region=us-central1 \
    --source=. \
    --entry-point=hello \
    --trigger-http \
    --allow-unauthenticated

# Test it
$ curl https://us-central1-my-project.cloudfunctions.net/hello?name=DevOps

Hello, DevOps!

HTTP Function (Node.js)

// index.js
const functions = require('@google-cloud/functions-framework');

functions.http('hello', (req, res) => {
  const name = req.query.name || 'World';
  res.send(`Hello, ${name}!`);
});

// package.json
{
  "dependencies": {
    "@google-cloud/functions-framework": "^3.0.0"
  }
}

Pub/Sub Triggered Function

# main.py
import base64
import functions_framework
from cloudevents.http import CloudEvent

@functions_framework.cloud_event
def process_message(cloud_event: CloudEvent):
    """Triggered by a Pub/Sub message."""
    data = base64.b64decode(cloud_event.data["message"]["data"]).decode()
    print(f"Received message: {data}")

# Deploy Pub/Sub function
$ gcloud functions deploy process-message \
    --gen2 \
    --runtime=python312 \
    --region=us-central1 \
    --source=. \
    --entry-point=process_message \
    --trigger-topic=my-topic

# Test by publishing a message
$ gcloud pubsub topics publish my-topic --message="Hello from Pub/Sub"

Cloud Storage Triggered Function

# main.py
import functions_framework
from cloudevents.http import CloudEvent

@functions_framework.cloud_event
def process_upload(cloud_event: CloudEvent):
    """Triggered when a file is uploaded to GCS."""
    data = cloud_event.data
    bucket = data["bucket"]
    name = data["name"]
    print(f"File uploaded: gs://{bucket}/{name}")

$ gcloud functions deploy process-upload \
    --gen2 \
    --runtime=python312 \
    --region=us-central1 \
    --source=. \
    --entry-point=process_upload \
    --trigger-event-filters="type=google.cloud.storage.object.v1.finalized" \
    --trigger-event-filters="bucket=my-uploads-bucket"

Environment Variables and Secrets

# Set environment variables
$ gcloud functions deploy hello \
    --gen2 \
    --runtime=python312 \
    --region=us-central1 \
    --source=. \
    --entry-point=hello \
    --trigger-http \
    --set-env-vars="ENV=production,LOG_LEVEL=info"

# Mount Secret Manager secrets
$ gcloud functions deploy hello \
    --gen2 \
    --runtime=python312 \
    --region=us-central1 \
    --source=. \
    --entry-point=hello \
    --trigger-http \
    --set-secrets="DB_PASSWORD=db-password:latest"

Scaling Configuration

# Set min and max instances
$ gcloud functions deploy hello \
    --gen2 \
    --runtime=python312 \
    --region=us-central1 \
    --source=. \
    --entry-point=hello \
    --trigger-http \
    --min-instances=1 \
    --max-instances=100 \
    --memory=512Mi \
    --cpu=1 \
    --concurrency=80 \
    --timeout=60s

Manage Functions

# List functions
$ gcloud functions list --region=us-central1

# View logs
$ gcloud functions logs read hello --region=us-central1 --gen2

# Describe a function
$ gcloud functions describe hello --region=us-central1 --gen2

# Delete a function
$ gcloud functions delete hello --region=us-central1 --gen2

Common Mistakes

Mistake	Why It’s Wrong	Fix
Using Gen 1 for new functions	Lower limits, no concurrency	Use --gen2
No min instances for production	Cold start latency	Set --min-instances=1
--allow-unauthenticated on internal	Security risk	Use IAM invoker role
No timeout set	Function runs too long	Set explicit --timeout
Large deployment package	Slow cold starts	Minimize dependencies

Quick Reference

Command	Description
gcloud functions deploy F --gen2 --trigger-http	Deploy HTTP function
gcloud functions deploy F --gen2 --trigger-topic=T	Deploy Pub/Sub function
gcloud functions list	List functions
gcloud functions logs read F	View logs
gcloud functions delete F	Delete function

Next → Cloud Run Serverless