GCP Cloud Run

Patterns

Cloud Run Service Pattern

Containerized web service on Cloud Run

When to use: 'Web applications and APIs', 'Need any runtime or library', 'Complex services with multiple endpoints', 'Stateless containerized workloads']

javascript

Dockerfile - Multi-stage build for smaller image

FROM node:20-slim AS builder WORKDIR /app COPY package.json ./ RUN npm ci --only=production

FROM node:20-slim WORKDIR /app

Copy only production dependencies

COPY --from=builder /app/node_modules ./node_modules COPY src ./src COPY package.json ./

Cloud Run uses PORT env variable

ENV PORT=8080 EXPOSE 8080

Run as non-root user

USER node

CMD "node", "src/index.js"]

// src/index.js const express = require('express'); const app = express();

app.use(express.json());

// Health check endpoint app.get('/health', (req, res) => { res.status(200).send('OK'); });

// API routes app.get('/api/items/:id', async (req, res) => { try { const item = await getItem(req.params.id); res.json(item); } catch (error) { console.error('Error:', error); res.status(500).json({ error: 'Internal server error' }); } });

// Graceful shutdown process.on('SIGTERM', () => { console.log('SIGTERM received, shutting down gracefully'); server.close(() => { console.log('Server closed'); process.exit(0); }); });

const PORT = process.env.PORT || 8080; const server = app.listen(PORT, () => { console.log(Server listening on port ${PORT}); });

cloudbuild.yaml

steps: # Build the container image

• name: 'gcr.io/cloud-builders/docker'

args: 'build', '-t', 'gcr.io/$PROJECT_ID/my-service:$COMMIT_SHA', '.']

# Push the container image

• name: 'gcr.io/cloud-builders/docker'

args: 'push', 'gcr.io/$PROJECT_ID/my-service:$COMMIT_SHA']

# Deploy to Cloud Run

• name: 'gcr.io/google.com/cloudsdktool/cloud-sdk'

entrypoint: gcloud args:

• 'run'
• 'deploy'
• 'my-service'
• '--image=gcr.io/$PROJECT_ID/my-service:$COMMIT_SHA'
• '--region=us-central1'
• '--platform=managed'
• '--allow-unauthenticated'
• '--memory=512Mi'
• '--cpu=1'
• '--min-instances=1'
• '--max-instances=100'

### Cloud Run Functions Pattern

Event-driven functions (formerly Cloud Functions)

**When to use**: ['Simple event handlers', 'Pub/Sub message processing', 'Cloud Storage triggers', 'HTTP webhooks']

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

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

javascript
// Pub/Sub Function
const functions = require('@google-cloud/functions-framework');

functions.cloudEvent('processPubSub', (cloudEvent) => {
  // Decode Pub/Sub message
  const message = cloudEvent.data.message;
  const data = message.data
    ? JSON.parse(Buffer.from(message.data, 'base64').toString())
    : {};

  console.log('Received message:', data);

  // Process message
  processMessage(data);
});

javascript
// Cloud Storage Function
const functions = require('@google-cloud/functions-framework');

functions.cloudEvent('processStorageEvent', async (cloudEvent) => {
  const file = cloudEvent.data;

  console.log(`Event: ${cloudEvent.type}`);
  console.log(`Bucket: ${file.bucket}`);
  console.log(`File: ${file.name}`);

  if (cloudEvent.type === 'google.cloud.storage.object.v1.finalized') {
    await processUploadedFile(file.bucket, file.name);
  }
});

bash
# Deploy HTTP function
gcloud functions deploy hello-http \
  --gen2 \
  --runtime nodejs20 \
  --trigger-http \
  --allow-unauthenticated \
  --region us-central1

# Deploy Pub/Sub function
gcloud functions deploy process-messages \
  --gen2 \
  --runtime nodejs20 \
  --trigger-topic my-topic \
  --region us-central1

# Deploy Cloud Storage function
gcloud functions deploy process-uploads \
  --gen2 \
  --runtime nodejs20 \
  --trigger-event-filters="type=google.cloud.storage.object.v1.finalized" \
  --trigger-event-filters="bucket=my-bucket" \
  --region us-central1

### Cold Start Optimization Pattern

Minimize cold start latency for Cloud Run

**When to use**: ['Latency-sensitive applications', 'User-facing APIs', 'High-traffic services']

1. Enable Startup CPU Boost

bash
gcloud run deploy my-service \
  --cpu-boost \
  --region us-central1

2. Set Minimum Instances

bash
gcloud run deploy my-service \
  --min-instances 1 \
  --region us-central1

3. Optimize Container Image

dockerfile
# Use distroless for minimal image
FROM node:20-slim AS builder
WORKDIR /app
COPY package*.json ./
RUN npm ci --only=production

FROM gcr.io/distroless/nodejs20-debian12
WORKDIR /app
COPY --from=builder /app/node_modules ./node_modules
COPY src ./src
CMD ["src/index.js"]

4. Lazy Initialize Heavy Dependencies

javascript
// Lazy load heavy libraries
let bigQueryClient = null;

function getBigQueryClient() {
  if (!bigQueryClient) {
    const { BigQuery } = require('@google-cloud/bigquery');
    bigQueryClient = new BigQuery();
  }
  return bigQueryClient;
}

// Only initialize when needed
app.get('/api/analytics', async (req, res) => {
  const client = getBigQueryClient();
  const results = await client.query({...});
  res.json(results);
});

5. Increase Memory (More CPU)

bash
# Higher memory = more CPU during startup
gcloud run deploy my-service \
  --memory 1Gi \
  --cpu 2 \
  --region us-central1

## Anti-Patterns

### ❌ CPU-Intensive Work Without Concurrency=1

**Why bad**: CPU is shared across concurrent requests. CPU-bound work
will starve other requests, causing timeouts.

### ❌ Writing Large Files to /tmp

**Why bad**: /tmp is an in-memory filesystem. Large files consume
your memory allocation and can cause OOM errors.

### ❌ Long-Running Background Tasks

**Why bad**: Cloud Run throttles CPU to near-zero when not handling
requests. Background tasks will be extremely slow or stall.

## ⚠️ Sharp Edges

| Issue | Severity | Solution |
|-------|----------|----------|
| Issue | high | ## Calculate memory including /tmp usage |
| Issue | high | ## Set appropriate concurrency |
| Issue | high | ## Enable CPU always allocated |
| Issue | medium | ## Configure connection pool with keep-alive |
| Issue | high | ## Enable startup CPU boost |
| Issue | medium | ## Explicitly set execution environment |
| Issue | medium | ## Set consistent timeouts |