azure-functions-basics

name	azure-functions-basics
description	To use serverless on Azure. Use when: Bindings and triggers; When the specific requirement for Azure Functions Basics arises in the project.

Purpose

To use serverless on Azure.

When to Use

• Bindings and triggers.
• When the specific requirement for Azure Functions Basics arises in the project.

Procedure

1. Project Initialization

Create a new Azure Functions project using the CLI.

# Install tools
npm install -g azure-functions-core-tools@4

# Initialize project (Node.js/TypeScript)
func init MyFunctionProj --typescript
cd MyFunctionProj

# Create a specific function (HTTP Trigger)
func new --name MyHttpTrigger --template "HTTP trigger" --authlevel "anonymous"

2. Defining Triggers and Bindings

Edit function.json (or use decorators in v4+) to define how the function is invoked.

// v4 Node.js model (index.ts)
import { app, HttpRequest, HttpResponseInit, InvocationContext } from "@azure/functions";

export async function MyHttpTrigger(request: HttpRequest, context: InvocationContext): HttpResponseInit {
    context.log(`Http function processed request for url "${request.url}"`);

    const name = request.query.get('name') || await request.text() || 'world';

    return { body: `Hello, ${name}!` };
};

app.http('MyHttpTrigger', {
    methods: ['GET', 'POST'],
    authLevel: 'anonymous',
    handler: MyHttpTrigger
});

3. Local Testing

Run the function locally before deploying.

npm start
# Function will be available at http://localhost:7071/api/MyHttpTrigger

4. Deployment

Deploy to Azure using the CLI or GitHub Actions.

# Via CLI
func azure functionapp publish <FunctionAppName>

Constraints

• Cold Starts: Be aware of latency for the first request after inactivity on "Consumption" plans.
• Statelessness: Functions must be stateless. Use Azure Durable Functions if you need state/orchestration.
• Execution Limit: Consumption plan functions have a default timeout of 5 minutes (max 10).

Expected Output

A serverless function deployed to Azure that responds to triggers (HTTP, Timer, Queue) without managing underlying server infrastructure.