Serverless computing allows you to run applications without managing the underlying infrastructure. With serverless architectures, cloud providers handle scaling, maintenance, and execution, so you only pay for the compute time your code actually uses.
This guide covers serverless Python applications, including Flask and Django, and how to deploy them using platforms like AWS Lambda, Azure Functions, and Google Cloud Functions.
1. What is Serverless Computing?
Serverless computing eliminates the need to manage servers. Instead, code runs in short-lived, event-driven functions. Common providers include:
- AWS Lambda (Amazon Web Services)
- Azure Functions (Microsoft Azure)
- Google Cloud Functions (Google Cloud)
- Vercel & Netlify (For web applications)
Key Benefits:
No server management
Automatic scaling
Cost-efficient (pay per execution)
Event-driven execution
2. Serverless Frameworks for Python
Several frameworks help in deploying serverless applications:
| Framework | Supports |
|---|---|
| AWS Lambda | Flask, Django, FastAPI |
| Azure Functions | Flask, Django, FastAPI |
| Google Cloud Functions | Flask, Django, FastAPI |
| Zappa | Flask, Django |
| Chalice | Flask-like apps for AWS |
| Serverless Framework | Multi-cloud |
3. Deploying a Flask App on AWS Lambda (Zappa)
AWS Lambda does not support Flask natively, so we use Zappa, which converts Flask apps into serverless applications.
3.1 Install Dependencies
pip install flask zappa
3.2 Create a Flask App (app.py)
from flask import Flask
app = Flask(__name__)
@app.route("/")
def home():
return "Hello, Serverless Flask!"
if __name__ == "__main__":
app.run()
3.3 Initialize Zappa
zappa init
This will prompt:
- AWS profile selection
- S3 bucket setup
- Python version selection
3.4 Deploy the Flask App
zappa deploy
3.5 Update or Rollback
zappa update # To update the app
zappa rollback # To revert to a previous version
3.6 Remove the Application
zappa undeploy
4. Deploying a Django App on AWS Lambda
Django apps are heavier, so we use Zappa to package and deploy.
4.1 Install Dependencies
pip install django zappa
4.2 Create a Django Project
django-admin startproject myproject
cd myproject
4.3 Configure Zappa
Run:
zappa init
Ensure settings.py includes:
import os
ALLOWED_HOSTS = ["*"]
4.4 Deploy the Django App
zappa deploy
4.5 Run Migrations on AWS Lambda
zappa manage "migrate"
5. Deploying Python Functions to Azure Functions
Azure Functions provide a serverless environment with event-driven execution.
5.1 Install Azure CLI & Functions Core Tools
pip install azure-functions
5.2 Create an Azure Function
func init myfunction --python
cd myfunction
func new --name HttpTrigger1 --template "HTTP trigger" --authlevel "anonymous"
5.3 Run Locally
func start
5.4 Deploy to Azure
az login
func azure functionapp publish <YOUR_APP_NAME>
6. Deploying Python Functions to Google Cloud Functions
Google Cloud Functions enable running Python code in response to HTTP requests.
6.1 Install Google Cloud SDK
pip install google-cloud-functions
6.2 Create a Cloud Function
def hello_world(request):
return "Hello, Serverless World!"
6.3 Deploy the Function
gcloud functions deploy hello_world --runtime python39 --trigger-http --allow-unauthenticated
7. Using Serverless Framework
The Serverless Framework provides multi-cloud deployment support.
7.1 Install Serverless CLI
npm install -g serverless
7.2 Create a Serverless Python App
serverless create --template aws-python --path my-app
cd my-app
7.3 Deploy
serverless deploy
8. Comparing Serverless Providers
| Feature | AWS Lambda | Azure Functions | Google Cloud Functions |
|---|---|---|---|
| Pricing Model | Pay per request | Pay per execution | Pay per execution |
| Scalability | High | High | High |
| Cold Start Issues | Yes | Yes | Yes |
| Native Python Support | Yes | Yes | Yes |