What are Azure Functions?

Azure Functions is a serverless compute service that allows you to run small pieces of code, or "functions," in the cloud without having to provision or manage infrastructure. It's event-driven, meaning your functions are typically triggered by an event. This could be anything from an HTTP request, a new file arriving in storage, a message on a queue, or a scheduled timer.

With Azure Functions, you can focus solely on writing the code that solves your business problem, and Azure handles the rest, including scaling, patching, and availability. This makes it an ideal choice for building event-driven applications, APIs, and microservices.

Key Concepts

  • Functions: Small, self-contained units of code that perform a specific task.
  • Triggers: Events that invoke a function. Examples include HTTP requests, timers, and changes in data sources.
  • Bindings: Declarative ways to connect to other Azure services and SaaS offerings. Bindings simplify your code by allowing you to interact with services without complex SDKs.
  • Serverless: You don't need to manage servers. Azure automatically provisions and scales compute resources.
  • Event-Driven: Functions execute in response to events.

Common Use Cases

  • Web APIs and Microservices: Quickly build RESTful APIs and microservices.
  • Real-time Data Processing: Process streaming data from IoT devices or logs.
  • Scheduled Tasks: Run background jobs or scheduled operations.
  • Event Handling: Respond to changes in Azure Storage, Service Bus, or other event sources.
  • Orchestration: Coordinate multiple functions and services using Azure Durable Functions.

Benefits

  • Cost-Effective: Pay only for the compute time you consume. The Consumption plan offers a generous free grant.
  • Scalability: Automatically scales based on demand.
  • Language Support: Supports a variety of programming languages including C#, F#, Java, JavaScript, PowerShell, Python, and TypeScript.
  • Developer Productivity: Focus on code, not infrastructure.
  • Integration: Seamless integration with other Azure services and third-party services.

Getting Started

You can start developing Azure Functions using your preferred tools and languages:

  • Azure Portal: For simple functions and quick prototyping.
  • Visual Studio Code: With the Azure Functions extension for a rich development experience.
  • Visual Studio: For .NET developers.
  • Azure CLI: For scripting and automation.

Explore the next article to create your first Azure Function!

Example: A Simple HTTP Triggered Function

Here's a conceptual example of an HTTP triggered function written in JavaScript:


module.exports = async function (context, req) {
    context.log('JavaScript 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. Pass a name in the query string or in the request body for a personalized response.";

    context.res = {
        status: 200,
        body: responseMessage
    };
};