Remove custom scheduling implementation and migrate to CronScheduler.AspNetCore

src/Promitor.Scraper.Host/Extensions/IServiceCollectionExtensions.cs

@@ -1,11 +1,10 @@
-using System;
-using System.IO;
+using System.IO;
 using System.Linq;
+using System.Threading.Tasks;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.DependencyInjection;
+using Promitor.Core.Telemetry.Interfaces;
 using Promitor.Scraper.Host.Scheduling;
-using Promitor.Scraper.Host.Scheduling.Infrastructure.Extensions;
-using Promitor.Scraper.Host.Scheduling.Interfaces;
 using Swashbuckle.AspNetCore.Swagger;
 
 // ReSharper disable once CheckNamespace
@@ -20,11 +19,10 @@ public static class IServiceCollectionExtensions
         /// <param name="services">Collections of services in application</param>
         public static void UseCronScheduler(this IServiceCollection services)
         {
-            services.AddSingleton<IScheduledTask, AzureMonitorScrapingTask>();
-            services.AddScheduler((sender, args) =>
+            services.AddScheduler(builder =>
             {
-                Console.Write(args.Exception.Message);
-                args.SetObserved();
+                builder.AddJob<MetricScrapingJob>();
+                builder.UnobservedTaskExceptionHandler = (sender, exceptionEventArgs) => UnobservedJobHandlerHandler(sender, exceptionEventArgs, services);
             });
         }
 
@@ -81,5 +79,14 @@ private static string GetXmlDocumentationPath(IServiceCollection services)
 
             return File.Exists(xmlDocumentationPath) ? xmlDocumentationPath : string.Empty;
         }
+
+        private static void UnobservedJobHandlerHandler(object sender, UnobservedTaskExceptionEventArgs e, IServiceCollection services)
+        {
+            var exceptionTrackerService = services.FirstOrDefault(service => service.ServiceType == typeof(IExceptionTracker));
+            var exceptionTracker = (IExceptionTracker)exceptionTrackerService?.ImplementationInstance;
+            exceptionTracker?.Track(e.Exception);
+
+            e.SetObserved();
+        }
     }
 }

src/Promitor.Scraper.Host/Promitor.Scraper.Host.csproj

@@ -33,9 +33,9 @@
   </ItemGroup>
 
   <ItemGroup>
+    <PackageReference Include="CronScheduler.AspNetCore" Version="1.0.11" />
     <PackageReference Include="Microsoft.AspNetCore.App" Version="2.2.3" />
     <PackageReference Include="Prometheus.Client.AspNetCore" Version="2.1.0" />
-    <PackageReference Include="Shuttle.Core.Cron" Version="10.0.6" />
     <PackageReference Include="Swashbuckle.AspNetCore" Version="4.0.1" />
     <PackageReference Include="Swashbuckle.AspNetCore.Annotations" Version="4.0.1" />
     <PackageReference Include="System.Net.Http" Version="4.3.4" />

src/Promitor.Scraper.Host/Scheduling/MetricScrapingJob.cs

@@ -0,0 +1,78 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using CronScheduler.AspNetCore;
+using GuardNet;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Logging;
+using Promitor.Core;
+using Promitor.Core.Scraping.Configuration.Model;
+using Promitor.Core.Scraping.Configuration.Model.Metrics;
+using Promitor.Core.Scraping.Configuration.Providers.Interfaces;
+using Promitor.Core.Scraping.Factories;
+using Promitor.Core.Telemetry.Interfaces;
+
+namespace Promitor.Scraper.Host.Scheduling
+{
+    public class MetricScrapingJob : IScheduledJob
+    {
+        private readonly IMetricsDeclarationProvider _metricsDeclarationProvider;
+        private readonly IExceptionTracker _exceptionTracker;
+        private readonly ILogger _logger;
+
+        public MetricScrapingJob(IMetricsDeclarationProvider metricsDeclarationProvider, ILogger logger, IExceptionTracker exceptionTracker)
+        {
+            Guard.NotNull(metricsDeclarationProvider, nameof(metricsDeclarationProvider));
+            Guard.NotNull(exceptionTracker, nameof(exceptionTracker));
+            Guard.NotNull(logger, nameof(logger));
+
+            _metricsDeclarationProvider = metricsDeclarationProvider;
+            _exceptionTracker = exceptionTracker;
+            _logger = logger;
+
+            ConfigureJob();
+        }
+
+        public string CronSchedule { get; set; }
+        public string CronTimeZone { get; }
+        public bool RunImmediately { get; set; }
+
+        private void ConfigureJob()
+        {
+            CronSchedule = Environment.GetEnvironmentVariable(EnvironmentVariables.Scraping.CronSchedule);
+            RunImmediately = false;
+        }
+
+        public async Task ExecuteAsync(CancellationToken cancellationToken)
+        {
+            _logger.LogInformation("Scraping Azure Monitor - {timestamp}", DateTimeOffset.Now);
+
+            try
+            {
+                var scrapeConfiguration = _metricsDeclarationProvider.Get();
+
+                var scrapingTasks = new List<Task>();
+
+                foreach (var metricDefinition in scrapeConfiguration.Metrics)
+                {
+                    var scrapingTask = ScrapeMetric(scrapeConfiguration.AzureMetadata, scrapeConfiguration.MetricDefaults, metricDefinition);
+                    scrapingTasks.Add(scrapingTask);
+                }
+                await Task.WhenAll(scrapingTasks);
+            }
+            catch (Exception exception)
+            {
+                _exceptionTracker.Track(exception);
+            }
+        }
+
+        private async Task ScrapeMetric(AzureMetadata azureMetadata, MetricDefaults metricDefaults, MetricDefinition metricDefinitionDefinition)
+        {
+            _logger.LogInformation("Scraping '{MetricName}' for resource type '{ResourceType}'", metricDefinitionDefinition.Name, metricDefinitionDefinition.ResourceType);
+
+            var scraper = MetricScraperFactory.CreateScraper(metricDefinitionDefinition.ResourceType, azureMetadata, metricDefaults, _logger, _exceptionTracker);
+            await scraper.ScrapeAsync(metricDefinitionDefinition);
+        }
+    }
+}

src/Promitor.Scraper.Host/Startup.cs

@@ -49,6 +49,7 @@ public void ConfigureServices(IServiceCollection services)
                         jsonOptions.SerializerSettings.Converters.Add(new Newtonsoft.Json.Converters.StringEnumConverter());
                         jsonOptions.SerializerSettings.NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore;
                     });
+
             services.UseCronScheduler();
             services.UseOpenApiSpecifications(ScrapeEndpointBasePath, apiVersion: 1);
         }