Azure Functions Overview

Azure Functions is a serverless compute service that lets you run event-driven code without explicitly provisioning or managing infrastructure. With Azure Functions, you can build applications by connecting various services, scale applications on-demand, and pay only for the resources you consume.

What are Serverless and Azure Functions?

Serverless computing allows you to build and run applications and services without thinking about servers. It's a cloud-native development model that powers Functions. You write code and the cloud provider manages the infrastructure to run that code, scaling it up or down as needed.

Azure Functions offers:

  • Event-driven: Code runs in response to events from Azure services or third-party sources.
  • Scalability: Automatically scales based on demand, handling millions of events per second.
  • Cost-effective: Pay only for the compute time you consume. No charge when your code isn't running.
  • Language support: Develop in your preferred language, including C#, F#, Java, JavaScript, Python, and TypeScript.
  • Integrated development: Develop locally using the Azure Functions Core Tools and deploy to the cloud.

Key Concepts

Functions

A function is a piece of code that executes in response to an event. Functions are triggered by specific events and can interact with other Azure services through input and output bindings.

Triggers

A trigger defines how a function is invoked. It's the event that causes your function to run. Examples include an HTTP request, a new message in a storage queue, or a new file uploaded to Azure Blob Storage.

Common triggers include:

  • HTTP Trigger
  • Timer Trigger
  • Blob Trigger
  • Queue Trigger
  • Event Grid Trigger

Bindings

Bindings are declarative ways to connect your function to other Azure services. They simplify your code by allowing you to access data from these services without writing custom integration code. Bindings can be either input or output.

An input binding pulls data into your function, while an output binding pushes data from your function to another service.

Example: An HTTP trigger starts a function, and an output binding writes a result to Azure Table Storage.

Common Use Cases

Azure Functions are ideal for a wide range of scenarios:

  • Web APIs and Microservices: Build lightweight APIs that scale automatically.
  • Real-time data processing: Process data from IoT devices, social media feeds, or logs.
  • Scheduled tasks: Run background jobs or scheduled maintenance tasks.
  • Event processing: Respond to changes in Azure Storage, Cosmos DB, or Event Hubs.
  • Orchestration: Use Durable Functions to orchestrate complex workflows involving multiple functions.
Pro Tip: Consider using Azure Durable Functions for building stateful workflows and orchestrating complex, long-running processes.

Hosting Options

Azure Functions can be hosted in several ways, offering flexibility for different needs:

  • Consumption Plan: The default serverless option. You pay per execution and resource consumption. Scales automatically.
  • Premium Plan: Provides pre-warmed instances for zero-cold-start execution, VNet connectivity, and longer run durations.
  • App Service Plan: Run functions on the same infrastructure as your App Service apps, ideal for predictable workloads or when consolidating resources.

Getting Started

To get started with Azure Functions, you can:

  1. Azure Portal: Create and manage functions directly in the browser.
  2. Azure Functions Core Tools: Develop and debug functions locally on your machine before deploying to Azure.
  3. IDE Integration: Use extensions for Visual Studio, VS Code, and IntelliJ for a seamless development experience.
Refer to the "Create Your First Function" tutorial for a step-by-step guide.