App Engine

Google App Engine is a fully managed Platform-as-a-Service (PaaS) that lets you build and deploy applications without managing infrastructure. It automatically handles scaling, load balancing, and server management.

Key Features:

1. Standard Environment - Runs in a sandboxed environment with fast scaling to zero. Supports Python, Java, Go, PHP, Node.js, Ruby.

2. Flexible Environment - Runs in Docker containers on Compute Engine VMs. Supports any language or runtime.

3. Auto-scaling - Scales from zero to millions of requests automatically.

4. Traffic splitting - Split traffic between versions for A/B testing and canary deployments.

5. Integrated services - Built-in integration with Cloud SQL, Cloud Storage, Memorystore, and Pub/Sub.

The below example shows a Python Flask app deployed to App Engine Standard.

app.yaml configuration file,

Deploy with gcloud,

gcloud app deploy
Deployed service [default] to [https://my-project.uc.r.appspot.com]

Standard vs Flexible Environment:

Standard - Scales to zero, free tier available, very fast scaling, limited runtime customization.

Flexible - Always runs at least one instance, full Docker support, longer startup time, more customization.