Monitoring a Website heath with Azure Functions

Sometimes you get your self in need to monitor a website's health or it's content for changes. Of course, there's plenty of options out there, but for the sake of curiosity, let's code our own to see what we can do. First things first. Everything you'll see here, you can achieve with the free tier of azure.

The main idea of our app will be to monitor website health (status code). To create a new Azure Function Project, follow the steps below.

Steps to create a azure function project

After creating the project, you'll have a few files. Open your main file and start coding. The main file will have a function called Run and you can code your request method. I've created an async method to make the request and log the output at the console. The full code you can see below.

using System;
using System.Linq;
using System.Net.Http;
using System.Threading.Tasks;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Host;
using Microsoft.Extensions.Logging;

namespace Sipmann.CheckMySite
{
    public static class HttpCheck
    {

        private static async Task GetTask(string url, ILogger log)
        {
            var request = new HttpRequestMessage(HttpMethod.Get, url);

            var client = new HttpClient();
            var response = await client.SendAsync(request);

            if (response.IsSuccessStatusCode)
            {
                log.LogInformation($"URL ${url} esta OK");
            }
            else
            {
                log.LogInformation($"URL ${url} não esta OK");
            }
        }

        [FunctionName("HttpCheck")]
        public static void Run([TimerTrigger("0 */5 * * * *")]TimerInfo myTimer, ILogger log)
        {
            var urls = new[]{"https://www.sipmann.com", "https://www.canezecanez.com.br"};

            // Start every request and wait for them all to complete
            Task.WaitAll(urls.Select(url => GetTask(url, log)).ToArray());
            log.LogInformation($"Finalizou a fila");
        }
    }
}

Now you can enhance the function and maybe send some alerts like a Telegram message when one of your sites went down.

Translations: