Cloud Run vs Cloud Functions decision in GCP - CLI Comparison

Introduction

Sometimes you need to run your code in the cloud without managing servers. Cloud Run and Cloud Functions both do this but work differently. Choosing the right one helps your app run smoothly and saves money.

When you want to run a simple function that responds to events like file uploads or messages.

When you need to run a full containerized app that can handle web requests with custom dependencies.

When you want automatic scaling without worrying about infrastructure.

When you want to pay only for the exact time your code runs.

When you want to deploy code quickly without building a container.

Commands

This command deploys a simple Cloud Function named helloWorld using Node.js 18 runtime. It triggers on HTTP requests and allows public access.

Terminal

gcloud functions deploy helloWorld --runtime nodejs18 --trigger-http --allow-unauthenticated

Expected Output

Deploying function (may take a while)...done.

availableMemoryMb: 256

entryPoint: helloWorld

httpsTrigger:

  url: https://REGION-PROJECT_ID.cloudfunctions.net/helloWorld

runtime: nodejs18

serviceAccountEmail: [e-mail]

status: ACTIVE

updateTime: '2024-06-01T12:00:00Z'

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--runtime - Specifies the language runtime environment

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--trigger-http - Sets the function to be triggered by HTTP requests

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--allow-unauthenticated - Allows public access without authentication

This command deploys a containerized app to Cloud Run named my-app. It uses a container image stored in Google Container Registry, runs on managed Cloud Run in us-central1, and allows public access.

Terminal

gcloud run deploy my-app --image gcr.io/my-project/my-app-image --platform managed --region us-central1 --allow-unauthenticated

Expected Output

Deploying container to Cloud Run service [my-app] in project [my-project] region [us-central1]

✓ Deploying new service... Done

  ✓ Creating Revision...

  ✓ Routing traffic...

Done.

Service [my-app] revision [my-app-00001-abc] has been deployed and is serving 100 percent of traffic.

Service URL: https://my-app-abcdefg-uc.a.run.app

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--image - Specifies the container image to deploy

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--platform - Specifies Cloud Run platform type

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--allow-unauthenticated - Allows public access without authentication

This command calls the deployed Cloud Function helloWorld to test it works.

Terminal

gcloud functions call helloWorld

Expected Output

result: Hello from Cloud Functions!

This command sends an HTTP request to the Cloud Run service URL to check the app is running.

Terminal

curl https://my-app-abcdefg-uc.a.run.app

Expected Output

Hello from Cloud Run!

Key Concept

If you remember nothing else from this pattern, remember: Cloud Functions are best for simple event-driven code, while Cloud Run is best for full container apps needing more control.

Common Mistakes

Trying to deploy complex apps as Cloud Functions without containers

Cloud Functions have limited runtime and environment control, causing failures or limitations

Use Cloud Run to deploy containerized apps with full control over dependencies and runtime

Not setting --allow-unauthenticated flag when public access is needed

The service will reject public requests, causing 403 errors

Add --allow-unauthenticated flag during deployment to allow public HTTP access

Using Cloud Run for very simple functions that don't need containers

It adds unnecessary complexity and cost for simple event-driven tasks

Use Cloud Functions for simple, short-lived event-driven code

Summary

Deploy Cloud Functions for simple event-driven code triggered by HTTP or events.

Deploy Cloud Run for containerized apps needing more control and custom dependencies.

Use gcloud commands to deploy and test both services with proper flags for access.