@azure/functions

What is @azure/functions?

@azure/functions is an npm package that provides tools and libraries for building and deploying serverless functions on the Azure platform. It allows developers to create event-driven applications that can respond to various triggers such as HTTP requests, timers, and messages from other Azure services.

What are @azure/functions's main functionalities?

HTTP Trigger

This feature allows you to create a function that responds to HTTP requests. The code sample demonstrates a simple HTTP-triggered function that returns a greeting message.

module.exports = async function (context, req) {
  context.log('HTTP trigger function processed a request.');
  const name = req.query.name || (req.body && req.body.name);
  const responseMessage = name
    ? `Hello, ${name}. This HTTP triggered function executed successfully.`
    : 'This HTTP triggered function executed successfully. Pass a name in the query string or in the request body for a personalized response.';
  context.res = {
    status: 200,
    body: responseMessage
  };
};

Timer Trigger

This feature allows you to create a function that runs on a schedule. The code sample demonstrates a timer-triggered function that logs the current timestamp.

module.exports = async function (context, myTimer) {
  var timeStamp = new Date().toISOString();
  if (myTimer.isPastDue) {
    context.log('Timer function is running late!');
  }
  context.log('Timer trigger function ran!', timeStamp);
};

Queue Trigger

This feature allows you to create a function that responds to messages in an Azure Storage Queue. The code sample demonstrates a queue-triggered function that logs the message content.

module.exports = async function (context, myQueueItem) {
  context.log('Queue trigger function processed work item', myQueueItem);
};

Other packages similar to @azure/functions

aws-lambda

aws-lambda is an npm package for building serverless functions on AWS Lambda. It provides similar functionalities to @azure/functions, such as handling HTTP requests, scheduled tasks, and processing messages from queues. However, it is designed specifically for the AWS ecosystem.

serverless

serverless is a framework-agnostic npm package that allows you to build and deploy serverless applications across multiple cloud providers, including AWS, Azure, and Google Cloud. It provides a unified experience for managing serverless functions, but requires additional configuration compared to provider-specific packages like @azure/functions.

README

Azure Functions Node.js Programming Model

Branch	Status	Support level	Node.js Versions
v4.x		Preview	20 (Preview), 18
v3.x (default)		GA (Recommended)	20 (Preview), 18, 16, 14

Install

npm install @azure/functions@preview

Documentation

• Azure Functions JavaScript Developer Guide
• Upgrade guide from v3 to v4
• Create your first TypeScript function
• Create your first JavaScript function

Considerations

• During preview, the v4 model requires you to set the app setting AzureWebJobsFeatureFlags to EnableWorkerIndexing. For more information, see Enable v4 programming model.
• The Node.js "programming model" shouldn't be confused with the Azure Functions "runtime".
  • Programming model: Defines how you author your code and is specific to JavaScript and TypeScript.
  • Runtime: Defines underlying behavior of Azure Functions and is shared across all languages.
• The programming model version is strictly tied to the version of the @azure/functions npm package, and is versioned independently of the runtime. Both the runtime and the programming model use "4" as their latest major version, but that is purely a coincidence.

Usage

TypeScript

import { app, HttpRequest, HttpResponseInit, InvocationContext } from "@azure/functions";

export async function httpTrigger1(request: HttpRequest, context: InvocationContext): Promise<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('httpTrigger1', {
    methods: ['GET', 'POST'],
    authLevel: 'anonymous',
    handler: httpTrigger1
});

JavaScript

const { app } = require('@azure/functions');

app.http('httpTrigger1', {
    methods: ['GET', 'POST'],
    authLevel: 'anonymous',
    handler: async (request, context) => {
        context.log(`Http function processed request for url "${request.url}"`);

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

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

Contributing

• Clone the repository locally and open in VS Code
• Run "Extensions: Show Recommended Extensions" from the command palette and install all extensions listed under "Workspace Recommendations"
• Run npm install
• Run npm run build
• Run npm link
• Create or open a local function app to test with
• In the local function app:
  • Run npm link @azure/functions. This will point your app to the local repository for the @azure/functions package
  • Add the following settings to your "local.settings.json" file or configure them directly as environment variables
    • languageWorkers__node__arguments: --inspect

      💡 Tip: Set logging__logLevel__Worker to debug if you want to view worker-specific logs in the output of func start

  • Start the app (i.e. run func start or press F5)
• Back in the framework repository, press F5 and select the process for your running function app
• Before you submit a PR, run npm test and fix any issues. If you want to debug the tests, switch your launch profile in VS Code to "Launch Unit Tests" and press F5.

Code of Conduct

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact [e-mail] with any additional questions or comments.

Contributing to type definitions

The type definitions are located in the types folder. Please make sure to update the tests in ./test/types/index.test.ts as well.