GCP Cloud Functions Overview
Google Cloud Functions enables event-driven serverless computing on Google Cloud Platform. Build functions with automatic scaling, integrated security, and seamless integration with Google Cloud services for rapid development.
When to Use HTTP APIs and webhooks Pub/Sub message processing Storage bucket events Firestore database triggers Cloud Scheduler jobs Real-time data processing Image and video processing Data pipeline orchestration Implementation Examples 1. Cloud Function Creation with gcloud CLI
Install Google Cloud SDK
curl https://sdk.cloud.google.com | bash exec -l $SHELL
Initialize and authenticate
gcloud init gcloud auth application-default login
Set project
gcloud config set project MY_PROJECT_ID
Create service account
gcloud iam service-accounts create cloud-function-sa \ --display-name "Cloud Function Service Account"
Grant permissions
gcloud projects add-iam-policy-binding MY_PROJECT_ID \ --member="serviceAccount:cloud-function-sa@MY_PROJECT_ID.iam.gserviceaccount.com" \ --role="roles/cloudfunctions.invoker"
Deploy HTTP function
gcloud functions deploy my-http-function \ --gen2 \ --runtime nodejs18 \ --region us-central1 \ --source ./src \ --entry-point httpHandler \ --trigger-http \ --allow-unauthenticated \ --timeout 60 \ --memory 256MB \ --max-instances 100 \ --set-env-vars NODE_ENV=production,API_KEY=xxx \ --service-account cloud-function-sa@MY_PROJECT_ID.iam.gserviceaccount.com
Deploy Pub/Sub function
gcloud functions deploy my-pubsub-function \ --gen2 \ --runtime nodejs18 \ --region us-central1 \ --source ./src \ --entry-point pubsubHandler \ --trigger-topic my-topic \ --memory 256MB \ --timeout 300 \ --service-account cloud-function-sa@MY_PROJECT_ID.iam.gserviceaccount.com
Deploy Cloud Storage function
gcloud functions deploy my-storage-function \ --gen2 \ --runtime nodejs18 \ --region us-central1 \ --source ./src \ --entry-point storageHandler \ --trigger-bucket my-bucket \ --trigger-location us-central1 \ --timeout 60 \ --service-account cloud-function-sa@MY_PROJECT_ID.iam.gserviceaccount.com
List functions
gcloud functions list
Get function details
gcloud functions describe my-http-function --gen2 --region us-central1
Call function
gcloud functions call my-http-function \ --region us-central1 \ --data '{"name":"John"}'
View logs
gcloud functions logs read my-http-function --limit 50 --gen2 --region us-central1
Delete function
gcloud functions delete my-http-function --gen2 --region us-central1
-
Cloud Functions Implementation (Node.js) // HTTP Trigger Function exports.httpHandler = async (req, res) => { try { // Enable CORS res.set('Access-Control-Allow-Origin', '*'); res.set('Access-Control-Allow-Methods', 'GET, POST, OPTIONS');
if (req.method === 'OPTIONS') { res.status(204).send(''); return; }
// Parse request const { name } = req.query;
if (!name) { return res.status(400).json({ error: 'Name is required' }); }
// Log with Cloud Logging console.log(JSON.stringify({ severity: 'INFO', message: 'Processing request', name: name, requestId: req.id }));
// Business logic const response = { message:
Hello ${name}!, timestamp: new Date().toISOString() };res.status(200).json(response); } catch (error) { console.error(JSON.stringify({ severity: 'ERROR', message: error.message, stack: error.stack }));
res.status(500).json({ error: 'Internal server error' }); } };
// Pub/Sub Trigger Function exports.pubsubHandler = async (message, context) => { try { // Decode Pub/Sub message const pubsubMessage = message.data ? Buffer.from(message.data, 'base64').toString() : null;
console.log('Received message:', pubsubMessage);
// Parse message
const data = JSON.parse(pubsubMessage);
// Process message asynchronously
await processMessage(data);
console.log('Message processed successfully');
} catch (error) { console.error('Error processing message:', error); throw error; // Function will retry } };
// Cloud Storage Trigger Function exports.storageHandler = async (file, context) => { try { const { name, bucket } = file;
console.log(JSON.stringify({
message: 'Processing storage event',
bucket: bucket,
file: name,
eventId: context.eventId,
eventType: context.eventType
}));
// Check file type
if (!name.endsWith('.jpg') && !name.endsWith('.png')) {
console.log('Skipping non-image file');
return;
}
// Process image
await processImage(bucket, name);
console.log('Image processed successfully');
} catch (error) { console.error('Error processing file:', error); throw error; } };
// Cloud Scheduler (CRON) Function exports.cronHandler = async (req, res) => { try { console.log('Scheduled job started');
// Run batch processing
await performBatchJob();
res.status(200).json({ message: 'Batch job completed' });
} catch (error) { console.error('Error in batch job:', error); res.status(500).json({ error: error.message }); } };
// Helper functions async function processMessage(data) { // Business logic return new Promise(resolve => { setTimeout(() => resolve(), 1000); }); }
async function processImage(bucket, filename) { // Use Cloud Vision API or similar return true; }
async function performBatchJob() { // Batch processing logic return true; }
- Terraform Cloud Functions Configuration
cloud-functions.tf
terraform { required_providers { google = { source = "hashicorp/google" version = "~> 5.0" } } }
provider "google" { project = var.project_id region = var.region }
variable "project_id" { description = "GCP Project ID" }
variable "region" { default = "us-central1" }
Service account for functions
resource "google_service_account" "function_sa" { account_id = "cloud-function-sa" display_name = "Cloud Function Service Account" }
Grant invoker role
resource "google_project_iam_member" "function_invoker" { project = var.project_id role = "roles/cloudfunctions.invoker" member = "serviceAccount:${google_service_account.function_sa.email}" }
Grant Cloud Logging role
resource "google_project_iam_member" "function_logs" { project = var.project_id role = "roles/logging.logWriter" member = "serviceAccount:${google_service_account.function_sa.email}" }
Source archive bucket
resource "google_storage_bucket" "function_source" { name = "${var.project_id}-function-source" location = var.region }
Upload function code
resource "google_storage_bucket_object" "function_zip" { name = "function-${data.archive_file.function.output_md5}.zip" bucket = google_storage_bucket.function_source.name source = data.archive_file.function.output_path }
Archive function code
data "archive_file" "function" { type = "zip" source_dir = "${path.module}/src" output_path = "${path.module}/function.zip" }
HTTP Cloud Function
resource "google_cloudfunctions2_function" "http_function" { name = "my-http-function" location = var.region description = "HTTP trigger function"
build_config { runtime = "nodejs18" entry_point = "httpHandler" source { storage_source { bucket = google_storage_bucket.function_source.name object = google_storage_bucket_object.function_zip.name } } }
service_config { max_instance_count = 100 available_memory_mb = 256 timeout_seconds = 60 service_account_email = google_service_account.function_sa.email
environment_variables = {
NODE_ENV = "production"
API_KEY = "your-api-key"
}
}
labels = { env = "production" } }
Allow public HTTP access
resource "google_cloudfunctions2_function_iam_member" "http_public" { cloud_function = google_cloudfunctions2_function.http_function.name role = "roles/cloudfunctions.invoker" member = "allUsers" }
Pub/Sub topic
resource "google_pubsub_topic" "messages" { name = "message-topic" }
Pub/Sub Cloud Function
resource "google_cloudfunctions2_function" "pubsub_function" { name = "my-pubsub-function" location = var.region description = "Pub/Sub trigger function"
build_config { runtime = "nodejs18" entry_point = "pubsubHandler" source { storage_source { bucket = google_storage_bucket.function_source.name object = google_storage_bucket_object.function_zip.name } } }
service_config { max_instance_count = 100 available_memory_mb = 256 timeout_seconds = 300 service_account_email = google_service_account.function_sa.email }
event_trigger { trigger_region = var.region event_type = "google.cloud.pubsub.topic.publish" pubsub_topic = google_pubsub_topic.messages.id } }
Cloud Storage bucket
resource "google_storage_bucket" "uploads" { name = "${var.project_id}-uploads" location = var.region }
Cloud Storage trigger function
resource "google_cloudfunctions2_function" "storage_function" { name = "my-storage-function" location = var.region description = "Cloud Storage trigger function"
build_config { runtime = "nodejs18" entry_point = "storageHandler" source { storage_source { bucket = google_storage_bucket.function_source.name object = google_storage_bucket_object.function_zip.name } } }
service_config { max_instance_count = 50 available_memory_mb = 256 timeout_seconds = 60 service_account_email = google_service_account.function_sa.email }
event_trigger { trigger_region = var.region event_type = "google.storage.object.finalize" resource = google_storage_bucket.uploads.name } }
Cloud Scheduler job (CRON)
resource "google_cloud_scheduler_job" "batch_job" { name = "batch-job-scheduler" description = "Scheduled batch job" schedule = "0 2 * * *" # Daily at 2 AM time_zone = "UTC" attempt_deadline = "320s" region = var.region
retry_config { retry_count = 1 }
http_target { uri = google_cloudfunctions2_function.http_function.service_config[0].uri http_method = "POST"
headers = {
"Content-Type" = "application/json"
}
body = base64encode(jsonencode({
job_type = "batch"
}))
oidc_token {
service_account_email = google_service_account.function_sa.email
}
} }
Cloud Logging sink
resource "google_logging_project_sink" "function_logs" { name = "cloud-function-logs" destination = "logging.googleapis.com/projects/${var.project_id}/logs/my-http-function"
filter = "resource.type=\"cloud_function\" AND resource.labels.function_name=\"my-http-function\"" }
Monitoring alert
resource "google_monitoring_alert_policy" "function_errors" { display_name = "Cloud Function Error Rate" combiner = "OR"
conditions { display_name = "Error rate threshold"
condition_threshold {
filter = "metric.type=\"cloudfunctions.googleapis.com/function/error_count\" AND resource.type=\"cloud_function\""
duration = "60s"
comparison = "COMPARISON_GT"
threshold_value = 10
aggregations {
alignment_period = "60s"
per_series_aligner = "ALIGN_RATE"
}
}
} }
output "http_function_url" { value = google_cloudfunctions2_function.http_function.service_config[0].uri }
Best Practices ✅ DO Use service accounts with least privilege Store secrets in Secret Manager Implement proper error handling Use environment variables for configuration Monitor with Cloud Logging and Cloud Monitoring Set appropriate memory and timeout Use event filters to reduce invocations Implement idempotent functions ❌ DON'T Store secrets in code Use default service account Create long-running functions Ignore error handling Deploy without testing Use unauthenticated access for sensitive functions Monitoring Cloud Logging for application logs Cloud Monitoring for metrics Error Reporting for error tracking Cloud Trace for distributed tracing Cloud Profiler for performance analysis Resources Google Cloud Functions Documentation Cloud Functions Best Practices Cloud Functions Terraform Provider