Azure Functions Documentation

Azure Functions Compute Options

Azure Functions is a serverless compute service that lets you run small pieces of code, or "functions," without managing infrastructure. It's event-driven and scales automatically. This section covers the core compute concepts and options available within Azure Functions.

Understanding the Compute Model

Azure Functions executes your code in response to triggers and bindings. The underlying compute infrastructure is managed by Azure, allowing you to focus solely on your business logic.

Hosting Options

Azure Functions offers several hosting options, each with different scalability, cost, and management characteristics:

• Consumption Plan: Automatically scales based on incoming events. You pay only for the compute time you consume. Ideal for event-driven workloads with varying traffic.
• Premium Plan: Provides pre-warmed instances to eliminate cold starts, VNet connectivity, and longer run times. Offers more predictable performance for critical applications.
• App Service Plan: Runs your functions on the same VMs as your App Service apps. Offers predictable costs and dedicated resources. Useful if you already have App Services deployed.
• Kubernetes: Deploy Azure Functions to an Azure Kubernetes Service (AKS) cluster for maximum control over the compute environment.

Triggers and Bindings

Functions are defined by triggers (what starts execution) and bindings (how data flows in and out). Common triggers include HTTP requests, timer events, and messages from queues or topics.

Example: HTTP Trigger

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.Extensions.Logging;
using System.IO;
using System.Threading.Tasks;

namespace MyFunctionsApp
{
    public static class HttpTriggerExample
    {
        [FunctionName("HttpTriggerExample")]
        public static async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req,
            ILogger log)
        {
            log.LogInformation("C# HTTP trigger function processed a request.");

            string name = req.Query["name"];
            string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
            dynamic data = Newtonsoft.Json.JsonConvert.DeserializeObject(requestBody);
            name = name ?? data?.name;

            string responseMessage = string.IsNullOrEmpty(name)
                ? "This HTTP triggered function executed successfully. Pass a name in the query string or in the request body for a personalized response."
                : $"Hello, {name}! This HTTP triggered function executed successfully.";

            return new OkObjectResult(responseMessage);
        }
    }
    

Scalability and Performance

Azure Functions automatically scales based on the selected hosting plan and the number of incoming events. The Consumption plan offers elastic scaling, while Premium and App Service plans provide more control and predictable performance.

Runtime Support

Azure Functions supports multiple programming languages and runtimes, including:

• .NET (C#, F#)
• Node.js
• Python
• Java
• PowerShell
• Custom Handlers (for other languages)