Azure Functions Monitor Pattern Example

using System;
using System.Threading.Tasks;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using System.Net.Http;
using Microsoft.Azure.WebJobs.Extensions.DurableTask;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Text;
using Microsoft.AspNetCore.Mvc;  //also see Project Packages section

//your namespace encapsulation here
   //your class encapsulation here

[FunctionName("MonitorPage_Trigger")]
public static async Task<IActionResult> HttpStart(
[HttpTrigger(AuthorizationLevel.Function, "get", Route = null)] HttpRequest req,
ILogger log, [DurableClient] IDurableOrchestrationClient starter)
{
    string instanceId = await starter.StartNewAsync("BeginMonitor", null);

    log.LogInformation($"Started orchestration with ID = '{instanceId}'.");

    return new OkObjectResult($"The Page monitor has started, you will get an email alert ONLY when Artemis-I has launched, if not, assume it hasn't launched");
}

private static readonly HttpClient httpClient = new HttpClient();

[FunctionName("BeginMonitor")]
public static async Task BeginMonitor(
[OrchestrationTrigger] IDurableOrchestrationContext context, ILogger log)
{

    if (!context.IsReplaying) {
    log.LogInformation($"Artemis launch page monitoring has begun"); 
    }

    //this is your cut off period where the Function will fully stop
    DateTime cutOffPeriod = context.CurrentUtcDateTime.AddMonths(2);

    string launchStatus = string.Empty;
    while(context.CurrentUtcDateTime < cutOffPeriod)
    {
        launchStatus =
          await context.CallActivityAsync<string>("CheckLiftOff", "has it launched yet!!");
        if (launchStatus == "We are going to space!!")
        {
            //send an alert here and then self-shutdown
            //also refer to Logic App section further down
            string logicAppUrl = "[YOUR_LOGIC_APP_URL]";

            var uri = new Uri(logicAppUrl);
            var request = new HttpRequestMessage(HttpMethod.Post, uri)
            {
                Content = new StringContent("{" + 
                $"\"launchStatus\":\"{launchStatus}\" " + "}",
                Encoding.UTF8, "application/json")
            };

            //call the logic app to send an email
            await httpClient.SendAsync(request);
            log.LogInformation($"Artemis launch page monitoring is now ending");
            break;
        }
        else
        {
            //try again on the next interval (in 24 hrs)
            log.LogInformation($"Artemis launch page monitoring is scheduling next retry");

            var nextCheckpoint = context.CurrentUtcDateTime.AddDays(1);

            await context.CreateTimer(nextCheckpoint, CancellationToken.None);
        }
    }

}

[FunctionName("CheckLiftOff")]
public static async Task<string> CheckLiftOff([ActivityTrigger] string inputData,
ILogger log)
{
    log.LogInformation($"Checking liftoff!!");
    var page = await httpClient.GetAsync("https://www.nasa.gov/artemis-1");
    var pageText = await page.Content.ReadAsStringAsync();

    //heavily simplified assertions here!!

    List<string> keyData = new List<string>()
    {
        "Artemis-I has launched",
        "Artemis-I has been launched",
        "Artemis-I MECO", //main engine cutoff
        "Artemis-I liftoff",
        "Godspeed",
        "MAX-Q reached",
        "Mach 1 reached",
        "Go Artemis go"
        //"Bravo" , "Capcom" // useful indicators of flight takeoff but unlikely 
        //to be written in a webpage,largely used in radio dialogue
    };

    var liftOffIndicatorCount =
      keyData.Count(x => pageText.ToLower().Contains(x.ToLower()));

    if (liftOffIndicatorCount > 1)
    {
    	log.LogInformation($"liftoff Confirmed!");

    	return "We are going to space!!";
    }
    else
    {
    	return "Not yet launched :(";
    }

}