Monitoring Queue Length with AzureFunctions w/MSI Auth to Storage Queue

MonitorMetrics.cs

using Microsoft.ApplicationInsights;
using Microsoft.ApplicationInsights.Extensibility;
using Microsoft.Azure.Services.AppAuthentication;
using Microsoft.Azure.WebJobs;
using Microsoft.Extensions.Logging;
using Microsoft.WindowsAzure.Storage;
using Microsoft.WindowsAzure.Storage.Auth;
using Microsoft.WindowsAzure.Storage.Queue;
using MyFunction.Extensions;
using System;
using System.Linq;
using System.Threading.Tasks;

namespace StorageFunctions
{
    public class MonitorMetrics
    {
        private static readonly string key = TelemetryConfiguration.Active.InstrumentationKey = Environment.GetEnvironmentVariable("APPINSIGHTS_INSTRUMENTATIONKEY", EnvironmentVariableTarget.Process);
        private static readonly TelemetryClient telemetry = new TelemetryClient() { InstrumentationKey = key };

        [FunctionName("MonitorQueueLength")]
        public static async Task MonitorQueueLength(
            [TimerTrigger("*/30 * * * * *")]TimerInfo myTimer,
            ExecutionContext context,
            ILogger log)
        {
            log.LogInformation($"C# Timer trigger function executed at: {DateTime.Now}");

            try
            {
                // connect to Azure Storage
                var queueClient = context.IsAzureEnvironment()
                    ? await CreateQueueClientAsync("your_storage_account_name")
                    : CreateQueueClient(Environment.GetEnvironmentVariable("queue_storage_connection_string"));

                var queueNames = new [] {"queuename" };
                var tasks = queueNames.Select(async x =>
                {
                    // get a reference to the queue and retrieve the queue length
                    var queue = queueClient.GetQueueReference(x);
                    await queue.FetchAttributesAsync();
                    var length = queue.ApproximateMessageCount;

                    // log the length
                    log.LogInformation($"{x}: {length}");
                    telemetry.GetMetric($"QueueLength.{x}").TrackValue(length);
                });
                await Task.WhenAll(tasks);
            }
            catch (Exception ex)
            {
                log.LogError($"{ex.Message}, {ex.GetType()}, {ex.StackTrace}");
            }
        }

        private static CloudQueueClient CreateQueueClient(string connectionString)
        {
            var account = CloudStorageAccount.Parse(connectionString);
            var queueClient = account.CreateCloudQueueClient();
            return queueClient;
        }

        private static async Task<CloudQueueClient> CreateQueueClientAsync(string storageAccountName)
        {
            var azureServiceTokenProvider = new AzureServiceTokenProvider();
            var accessToken = await azureServiceTokenProvider.GetAccessTokenAsync("https://storage.azure.com/");
            var tokenCredential = new TokenCredential(accessToken);
            var storageCredentials = new StorageCredentials(tokenCredential);
            var queueClient = new CloudQueueClient(new StorageUri(new Uri($"https://{storageAccountName}.queue.core.windows.net")), storageCredentials);
            return queueClient;
        }
    }
}