Azure Functions runs Python code on Microsoft’s serverless platform, integrating with Azure services, Cosmos DB, and Event Grid.

Setup

Install the Azure Functions Core Tools and Azure CLI:

  # macOS
brew tap azure/functions
brew install azure-functions-core-tools@4

# Verify
func --version
az --version

Create a Function App 

  func init MyFunctionApp --python
cd MyFunctionApp
func new --name HttpTrigger --template "HTTP trigger" --authlevel anonymous

This creates:

  MyFunctionApp/
├── function_app.py
├── host.json
├── local.settings.json
└── requirements.txt

HTTP Trigger Function 

  # function_app.py
import azure.functions as func
import json

app = func.FunctionApp()

@app.route(route="hello", auth_level=func.AuthLevel.ANONYMOUS)
def hello(req: func.HttpRequest) -> func.HttpResponse:
    name = req.params.get('name', 'World')
    return func.HttpResponse(f"Hello, {name}!")

@app.route(route="items", methods=["GET", "POST"])
def items(req: func.HttpRequest) -> func.HttpResponse:
    if req.method == "GET":
        return func.HttpResponse(
            json.dumps([{"id": 1, "name": "Item 1"}]),
            mimetype="application/json",
        )

    body = req.get_json()
    return func.HttpResponse(
        json.dumps({"id": 2, "name": body["name"]}),
        status_code=201,
        mimetype="application/json",
    )

Local Development 

  # Create virtual environment
python -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt

# Run locally
func start
# Visit http://localhost:7071/api/hello?name=Alice

Deploy to Azure 

  # Login
az login

# Create resource group and storage account
az group create --name MyResourceGroup --location eastus
az storage account create --name mystorageaccount --location eastus --resource-group MyResourceGroup --sku Standard_LRS

# Create function app
az functionapp create \
    --resource-group MyResourceGroup \
    --consumption-plan-location eastus \
    --runtime python \
    --runtime-version 3.12 \
    --functions-version 4 \
    --name my-python-function-app \
    --storage-account mystorageaccount

# Deploy
func azure functionapp publish my-python-function-app

Blob Storage Trigger

Process files uploaded to Azure Blob Storage:

  @app.blob_trigger(arg_name="myblob", path="uploads/{name}", connection="AzureWebJobsStorage")
def blob_processor(myblob: func.InputStream):
    print(f"Processing blob: {myblob.name}, Size: {myblob.length} bytes")
    content = myblob.read().decode('utf-8')
    # Process content...

Timer Trigger

Run on a schedule (cron expression):

  @app.timer_trigger(schedule="0 0 8 * * *", arg_name="timer", run_on_startup=False)
def daily_report(timer: func.TimerRequest) -> None:
    print("Generating daily report...")
    # Generate and send report...

Application Settings

Store configuration in local.settings.json (local) or Azure App Settings (production):

  {
  "IsEncrypted": false,
  "Values": {
    "AzureWebJobsStorage": "UseDevelopmentStorage=true",
    "FUNCTIONS_WORKER_RUNTIME": "python",
    "DATABASE_URL": "your-connection-string"
  }
}

Access in code:

  import os
db_url = os.environ["DATABASE_URL"]

Best Practices

  1. Use the v2 programming model (function_app.py with decorators)
  2. Store secrets in Azure Key Vault, not in code or settings files
  3. Use Application Insights for monitoring and debugging
  4. Set appropriate timeout and memory in host.json
  5. Use Durable Functions for complex orchestration workflows

Azure Functions is the natural choice when your infrastructure runs on Microsoft Azure.