Singleton eternal function with watchdog timer

SingletonEternalFunctionWithWatchdogTimer.cs

using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.DurableTask;
using Microsoft.Extensions.Logging;
using System;
using System.Threading;
using System.Threading.Tasks;

namespace DurableFunctionsPatterns
{
	public class EternalFunctionWithWatchdogTimer
	{
		private const string FunctionName = "EternalFunctionWithWatchdogTimer";
		private const string UniqueInstanceId = "MyBackgroundProcess";
		private const string EveryMinute = "0 */1 * * * *";
    
		private readonly ILogger<Orchestrator> _logger;

		public EternalFunctionWithWatchdogTimer(ILogger<Orchestrator> logger)
		{
			_logger = logger;
		}

		[FunctionName(FunctionName+"_WatchdogTimer")]
		public async Task TimerStart(
			[TimerTrigger(EveryMinute, RunOnStartup = true)]
			TimerInfo timer,
			[DurableClient] IDurableOrchestrationClient starter)
		{
			await EnsureRunning(starter);
		}

		private async Task EnsureRunning(IDurableOrchestrationClient starter)
		{
			// Check if an instance with the specified ID already exists or an existing one stopped running(completed/failed/terminated).
			var existingInstance = await starter.GetStatusAsync(UniqueInstanceId);
			if (existingInstance == null
			    || existingInstance.RuntimeStatus == OrchestrationRuntimeStatus.Completed
			    || existingInstance.RuntimeStatus == OrchestrationRuntimeStatus.Failed
			    || existingInstance.RuntimeStatus == OrchestrationRuntimeStatus.Terminated)
			{
				var startedInstance = await starter.StartNewAsync(FunctionName, instanceId: UniqueInstanceId);
				_logger.LogInformation("Started orchestration {instance}'.", UniqueInstanceId);
			}
			else
			{
				_logger.LogDebug($"Orchestration {UniqueInstanceId} is running.");
			}

		}

		private Random random = new Random(DateTime.UtcNow.Millisecond);

		[FunctionName(FunctionName)]
		public async Task RunOrchestrator(
			[OrchestrationTrigger] IDurableOrchestrationContext context)
		{
			_logger.LogInformation($"Do stuff {context.InstanceId}");

			if (random.Next(10) > 7)
			{
				throw new InvalidOperationException("Random exception that terminates the orchestrator");
			}

			// sleep for a while
			DateTime nextCleanup = context.CurrentUtcDateTime.AddSeconds(20);
			await context.CreateTimer(nextCleanup, CancellationToken.None);

			_logger.LogInformation($"Wake up {context.InstanceId}");

			context.ContinueAsNew(null);
		}
	}
}