Creating Serverless Applications with Azure Functions

Introduction

Azure Functions is a serverless compute service that enables you to run event-triggered code without having to explicitly provision or manage infrastructure. This tutorial will guide you through the process of creating a serverless application using Azure Functions in .NET.

Setting Up Your Environment

Before you begin, you need to set up your development environment.

Prerequisites

Azure Subscription
Visual Studio 2019 or later
Azure Functions Core Tools
Azure CLI

Creating an Azure Functions Project

Let's start by creating a new Azure Functions project in Visual Studio.

Steps to Create a New Project

// Step 1: Open Visual Studio and create a new project
// Step 2: Select 'Azure Functions' from the project templates
// Step 3: Configure the new project and click 'Create'
// Step 4: Select the trigger type (e.g., HTTP trigger) and click 'Create'

Understanding the Project Structure

The newly created project contains several files and folders:

Project Structure

- MyFunctionApp
  - Function1.cs
  - local.settings.json
  - host.json
  - bin
  - obj

Creating Your First Function

Let's create a simple HTTP-triggered function that returns a greeting message.

Function1.cs

using System.IO;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;

public static class Function1
{
    [FunctionName("Function1")]
    public static async Task 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 = JsonConvert.DeserializeObject(requestBody);
        name = name ?? data?.name;

        return name != null
            ? (ActionResult)new OkObjectResult($"Hello, {name}")
            : new BadRequestObjectResult("Please pass a name on the query string or in the request body");
    }
}

Running the Function Locally

You can run and test your Azure Function locally before deploying it to Azure.

Steps to Run Locally

// Step 1: Press F5 in Visual Studio to start the function app
// Step 2: Use a tool like Postman or your web browser to send a request to the function
// Example URL: http://localhost:7071/api/Function1?name=Azure

Deploying to Azure

Once you have tested your function locally, you can deploy it to Azure.

Steps to Deploy

// Step 1: Open the Command Palette in Visual Studio (Ctrl+Shift+P)
// Step 2: Select 'Azure Functions: Deploy to Function App'
// Step 3: Follow the prompts to create a new Function App in Azure or select an existing one
// Step 4: Once the deployment is complete, you can test the function in the Azure portal

Monitoring and Scaling

Azure Functions provides built-in monitoring and scaling capabilities. You can view logs, set up alerts, and configure scaling options in the Azure portal.

Monitoring in Azure Portal

// Step 1: Go to your Function App in the Azure portal
// Step 2: Click on 'Monitoring' in the left-hand menu
// Step 3: View logs, set up alerts, and configure scaling options

Conclusion

In this tutorial, you learned how to create a serverless application using Azure Functions, including setting up your environment, creating and running a function locally, deploying to Azure, and monitoring and scaling your function app.