feat: Provide support for batch scraping

.github/workflows/templates-build-push-image.yml

@@ -50,4 +50,4 @@ jobs:
           context: ./src/
           file: ./src/${{ inputs.project_name }}/Dockerfile.linux
           tags: ${{ env.image_commit_uri }},${{ env.image_latest_uri }}
-          push: true
+          push: true

src/Promitor.Agents.Scraper/Scheduling/ResourcesScrapingJob.cs

@@ -15,6 +15,7 @@
 using Promitor.Core.Extensions;
 using Promitor.Core.Metrics.Interfaces;
 using Promitor.Core.Metrics.Sinks;
+using Promitor.Core.Scraping.Batching;
 using Promitor.Core.Scraping.Configuration.Model;
 using Promitor.Core.Scraping.Configuration.Model.Metrics;
 using Promitor.Core.Scraping.Factories;
@@ -134,7 +135,6 @@ public async Task ExecuteAsync(CancellationToken cancellationToken)
             try
             {
                 var scrapeDefinitions = await GetAllScrapeDefinitions(cancellationToken);
-
                 await ScrapeMetrics(scrapeDefinitions, cancellationToken);
             }
             catch (OperationCanceledException)
@@ -251,22 +251,59 @@ private void GetResourceScrapeDefinition(IAzureResourceDefinition resourceDefini
         }
 
         private async Task ScrapeMetrics(IEnumerable<ScrapeDefinition<IAzureResourceDefinition>> scrapeDefinitions, CancellationToken cancellationToken)
-        {
+        {   
             var tasks = new List<Task>();
+            var batchScrapingEnabled = this._azureMonitorIntegrationConfiguration.Value.MetricsBatching?.Enabled ?? false;
+            if (batchScrapingEnabled) {
+                Logger.LogInformation("Promitor Scraper with operate in batch scraping mode, with max batch size {BatchSize}", this._azureMonitorIntegrationConfiguration.Value.MetricsBatching.MaxBatchSize);
+                Logger.LogWarning("Batch scraping is an experimental feature. See Promitor.io for its limitations and cost considerations");
+
+                var batchScrapeDefinitions = AzureResourceDefinitionBatching.GroupScrapeDefinitions(scrapeDefinitions, this._azureMonitorIntegrationConfiguration.Value.MetricsBatching.MaxBatchSize);
+
+                foreach(var batchScrapeDefinition in batchScrapeDefinitions) {
+                    var azureMetricName = batchScrapeDefinition.ScrapeDefinitionBatchProperties.AzureMetricConfiguration.MetricName;
+                    var resourceType = batchScrapeDefinition.ScrapeDefinitionBatchProperties.ResourceType;
+                    Logger.LogInformation("Executing batch scrape job of size {BatchSize} for Azure Metric {AzureMetricName} for resource type {ResourceType}.", batchScrapeDefinition.ScrapeDefinitions.Count, azureMetricName, resourceType);
+                    await ScheduleLimitedConcurrencyAsyncTask(tasks, () => ScrapeMetricBatched(batchScrapeDefinition), cancellationToken);
+                }
+            } else {
+                foreach (var scrapeDefinition in scrapeDefinitions)
+                {
+                    cancellationToken.ThrowIfCancellationRequested();
 
-            foreach (var scrapeDefinition in scrapeDefinitions)
-            {
-                cancellationToken.ThrowIfCancellationRequested();
-
-                var metricName = scrapeDefinition.PrometheusMetricDefinition.Name;
-                var resourceType = scrapeDefinition.Resource.ResourceType;
-                Logger.LogInformation("Scraping {MetricName} for resource type {ResourceType}.", metricName, resourceType);
+                    var metricName = scrapeDefinition.PrometheusMetricDefinition.Name;
+                    var resourceType = scrapeDefinition.Resource.ResourceType;
+                    Logger.LogInformation("Scraping {MetricName} for resource type {ResourceType}.", metricName, resourceType);
 
-                await ScheduleLimitedConcurrencyAsyncTask(tasks, () => ScrapeMetric(scrapeDefinition), cancellationToken);
+                    await ScheduleLimitedConcurrencyAsyncTask(tasks, () => ScrapeMetric(scrapeDefinition), cancellationToken);
+                }
             }
 
             await Task.WhenAll(tasks);
         }
+        private async Task ScrapeMetricBatched(BatchScrapeDefinition<IAzureResourceDefinition> batchScrapeDefinition) {
+            try
+            {
+                var resourceSubscriptionId = batchScrapeDefinition.ScrapeDefinitionBatchProperties.SubscriptionId;
+                var azureMonitorClient = _azureMonitorClientFactory.CreateIfNotExists(_metricsDeclaration.AzureMetadata.Cloud, _metricsDeclaration.AzureMetadata.TenantId,
+                    resourceSubscriptionId, _metricSinkWriter, _azureScrapingSystemMetricsPublisher, _resourceMetricDefinitionMemoryCache, _configuration,
+                    _azureMonitorIntegrationConfiguration, _azureMonitorLoggingConfiguration, _loggerFactory);
+                var azureEnvironent = _metricsDeclaration.AzureMetadata.Cloud.GetAzureEnvironment();
+
+                var tokenCredential = AzureAuthenticationFactory.GetTokenCredential(azureEnvironent.ManagementEndpoint, _metricsDeclaration.AzureMetadata.TenantId,
+                    AzureAuthenticationFactory.GetConfiguredAzureAuthentication(_configuration), new Uri(_metricsDeclaration.AzureMetadata.Cloud.GetAzureEnvironment().AuthenticationEndpoint));
+                var logAnalyticsClient = new LogAnalyticsClient(_loggerFactory, azureEnvironent, tokenCredential);
+
+                var scraper = _metricScraperFactory.CreateScraper(batchScrapeDefinition.ScrapeDefinitionBatchProperties.ResourceType, _metricSinkWriter, _azureScrapingSystemMetricsPublisher, azureMonitorClient, logAnalyticsClient);
+
+                await scraper.BatchScrapeAsync(batchScrapeDefinition);
+            }
+            catch (Exception ex)
+            {
+                Logger.LogError(ex, "Failed to scrape metric {MetricName} for resource batch {ResourceName}. Details: {Details}",
+                    batchScrapeDefinition.ScrapeDefinitionBatchProperties.PrometheusMetricDefinition.Name, batchScrapeDefinition.ScrapeDefinitionBatchProperties.ResourceType, ex.ToString());
+            }
+        }
 
         private async Task ScrapeMetric(ScrapeDefinition<IAzureResourceDefinition> scrapeDefinition)
         {
@@ -287,6 +324,7 @@ private async Task ScrapeMetric(ScrapeDefinition<IAzureResourceDefinition> scrap
                 var logAnalyticsClient = new LogAnalyticsClient(_loggerFactory, azureEnvironent, tokenCredential);
 
                 var scraper = _metricScraperFactory.CreateScraper(scrapeDefinition.Resource.ResourceType, _metricSinkWriter, _azureScrapingSystemMetricsPublisher, azureMonitorClient, logAnalyticsClient);
+
                 await scraper.ScrapeAsync(scrapeDefinition);
             }
             catch (Exception ex)

src/Promitor.Core.Scraping/AzureMonitorScraper.cs

@@ -1,10 +1,13 @@
 using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
+using System.Collections.Immutable;
 using System.Linq;
 using System.Threading.Tasks;
 using GuardNet;
 using Microsoft.Extensions.Logging;
 using Promitor.Core.Contracts;
+using Promitor.Core.Extensions;
 using Promitor.Core.Metrics;
 using Promitor.Core.Scraping.Configuration.Model;
 using Promitor.Core.Scraping.Configuration.Model.Metrics;
@@ -18,13 +21,19 @@ namespace Promitor.Core.Scraping
     /// <typeparam name="TResourceDefinition">Type of metric definition that is being used</typeparam>
     public abstract class AzureMonitorScraper<TResourceDefinition> : Scraper<TResourceDefinition>
         where TResourceDefinition : class, IAzureResourceDefinition
-    {
+    {   
+        /// <summary>
+        ///     A cache to store resource definitions. Used to hydrate resource info from resource ID, when processing batch query results
+        /// </summary>
+        private readonly ConcurrentDictionary<string, Tuple<IAzureResourceDefinition, TResourceDefinition>> _resourceDefinitions; // using a dictionary for now since IMemoryCache involves layers of injection
+
         /// <summary>
         ///     Constructor
         /// </summary>
         protected AzureMonitorScraper(ScraperConfiguration scraperConfiguration) :
             base(scraperConfiguration)
         {
+            _resourceDefinitions = new ConcurrentDictionary<string, Tuple<IAzureResourceDefinition, TResourceDefinition>>();
         }
 
         /// <inheritdoc />
@@ -73,6 +82,69 @@ protected override async Task<ScrapeResult> ScrapeResourceAsync(string subscript
             return new ScrapeResult(subscriptionId, scrapeDefinition.ResourceGroupName, resourceDefinition.ResourceName, resourceUri, finalMetricValues, metricLabels);
         }
 
+        protected override async Task<List<ScrapeResult>> BatchScrapeResourceAsync(string subscriptionId, BatchScrapeDefinition<IAzureResourceDefinition> batchScrapeDefinition, PromitorMetricAggregationType aggregationType, TimeSpan aggregationInterval)
+        {
+            Guard.NotNull(batchScrapeDefinition, nameof(batchScrapeDefinition));
+            Guard.NotLessThan(batchScrapeDefinition.ScrapeDefinitions.Count(), 1, nameof(batchScrapeDefinition));
+            Guard.NotNull(batchScrapeDefinition.ScrapeDefinitionBatchProperties.AzureMetricConfiguration, nameof(batchScrapeDefinition.ScrapeDefinitionBatchProperties.AzureMetricConfiguration));
+
+            var metricName = batchScrapeDefinition.ScrapeDefinitionBatchProperties.AzureMetricConfiguration.MetricName;
+
+            // Build list of resource URIs based on definitions in the batch 
+            var resourceUriList = new List<string>();
+            foreach (ScrapeDefinition<IAzureResourceDefinition> scrapeDefinition in batchScrapeDefinition.ScrapeDefinitions)
+            {
+                var resourceUri = $"/{BuildResourceUri(subscriptionId, scrapeDefinition, (TResourceDefinition) scrapeDefinition.Resource)}";
+                resourceUriList.Add(resourceUri);
+                // cache resource info 
+                // the TResourceDefinition resource definition attached to scrape definition can sometimes missing some attributes, need to them in here 
+                var resourceDefinitionToCache = new AzureResourceDefinition
+                (
+                    resourceType: scrapeDefinition.Resource.ResourceType, 
+                    resourceGroupName:  scrapeDefinition.ResourceGroupName, 
+                    subscriptionId: scrapeDefinition.SubscriptionId, 
+                    resourceName: scrapeDefinition.Resource.ResourceName
+                ); 
+                _resourceDefinitions.AddOrUpdate(resourceUri, new Tuple<IAzureResourceDefinition, TResourceDefinition>(resourceDefinitionToCache, (TResourceDefinition)scrapeDefinition.Resource), (newTuple, oldTuple) => oldTuple);
+            }
+
+            var metricLimit = batchScrapeDefinition.ScrapeDefinitionBatchProperties.AzureMetricConfiguration.Limit;
+            var dimensionNames = DetermineMetricDimensions(metricName, (TResourceDefinition) batchScrapeDefinition.ScrapeDefinitions[0].Resource, batchScrapeDefinition.ScrapeDefinitionBatchProperties.AzureMetricConfiguration); // TODO: resource definition doesn't seem to be used, can we remove it from function signature?  
+
+            var resourceIdTaggedMeasuredMetrics = new List<ResourceAssociatedMeasuredMetric>();
+            try
+            {
+                // Query Azure Monitor for metrics
+                resourceIdTaggedMeasuredMetrics = await AzureMonitorClient.BatchQueryMetricAsync(metricName, dimensionNames, aggregationType, aggregationInterval, resourceUriList, null, metricLimit);
+            }
+            catch (MetricInformationNotFoundException metricsNotFoundException)
+            {
+                Logger.LogWarning("No metric information found for metric {MetricName} with dimensions {MetricDimensions}. Details: {Details}", metricsNotFoundException.Name, metricsNotFoundException.Dimensions, metricsNotFoundException.Details);
+
+                var measuredMetric = dimensionNames.Count > 0
+                            ? MeasuredMetric.CreateForDimensions(dimensionNames) 
+                            : MeasuredMetric.CreateWithoutDimensions(null);
+                resourceIdTaggedMeasuredMetrics.Add(measuredMetric.WithResourceIdAssociation(null));
+            }
+
+            var scrapeResults = new List<ScrapeResult>();
+            // group based on resource, then do enrichment per group
+            var groupedMeasuredMetrics = resourceIdTaggedMeasuredMetrics.GroupBy(measuredMetric => measuredMetric.ResourceId);
+            foreach (IGrouping<string, ResourceAssociatedMeasuredMetric> resourceMetricsGroup in groupedMeasuredMetrics) 
+            {
+                var resourceId = resourceMetricsGroup.Key; 
+                if (_resourceDefinitions.TryGetValue(resourceId, out Tuple<IAzureResourceDefinition, TResourceDefinition> resourceDefinitionTuple))
+                {
+                    var resourceDefinition = resourceDefinitionTuple.Item1;
+                    var metricLabels = DetermineMetricLabels(resourceDefinitionTuple.Item2);
+                    var finalMetricValues = EnrichMeasuredMetrics(resourceDefinitionTuple.Item2, dimensionNames, resourceMetricsGroup.ToImmutableList());
+                    scrapeResults.Add(new ScrapeResult(subscriptionId, resourceDefinition.ResourceGroupName, resourceDefinition.ResourceName, resourceId, finalMetricValues, metricLabels));
+                }
+            }
+
+            return scrapeResults;
+        }
+
         private int? DetermineMetricLimit(ScrapeDefinition<IAzureResourceDefinition> scrapeDefinition)
         {
             return scrapeDefinition.AzureMetricConfiguration.Limit;
@@ -89,9 +161,9 @@ protected override async Task<ScrapeResult> ScrapeResourceAsync(string subscript
         /// <param name="dimensionNames">List of names of the specified dimensions provided by the scraper.</param>
         /// <param name="metricValues">Measured metric values that were found</param>
         /// <returns></returns>
-        protected virtual List<MeasuredMetric> EnrichMeasuredMetrics(TResourceDefinition resourceDefinition, List<string> dimensionNames, List<MeasuredMetric> metricValues)
+        protected virtual List<MeasuredMetric> EnrichMeasuredMetrics(TResourceDefinition resourceDefinition, List<string> dimensionNames, IReadOnlyList<MeasuredMetric> metricValues)
         {
-            return metricValues;
+            return metricValues.ToList();
         }
 
         /// <summary>

src/Promitor.Core.Scraping/Batching/AzureResourceDefinitionBatching.cs

@@ -0,0 +1,39 @@
+using System.Collections.Generic;
+using System.Linq;
+using Promitor.Core.Contracts;
+using Promitor.Core.Scraping.Configuration.Model.Metrics;
+
+namespace Promitor.Core.Scraping.Batching
+{
+    public static class AzureResourceDefinitionBatching
+    {
+        /// <summary>
+        /// groups scrape definitions based on following conditions:
+        /// 1. Definitions in a batch must target the same resource type 
+        /// 2. Definitions in a batch must target the same Azure metric with identical dimensions
+        /// 3. Definitions in a batch must have the same time granularity 
+        /// 4. Batch size cannot exceed configured maximum 
+        /// <see href="https://learn.microsoft.com/en-us/azure/azure-monitor/essentials/migrate-to-batch-api?tabs=individual-response#batching-restrictions"/> 
+        /// </summary>
+        public static List<BatchScrapeDefinition<IAzureResourceDefinition>> GroupScrapeDefinitions(IEnumerable<ScrapeDefinition<IAzureResourceDefinition>> allScrapeDefinitions, int maxBatchSize) 
+        {
+            return  allScrapeDefinitions.GroupBy(def => def.BuildScrapingBatchInfo()) 
+                        .ToDictionary(group => group.Key, group => group.ToList()) // first pass to build batches that could exceed max 
+                        .ToDictionary(group => group.Key, group => SplitScrapeDefinitionBatch(group.Value, maxBatchSize)) // split to right-sized batches 
+                        .SelectMany(group => group.Value.Select(batch => new BatchScrapeDefinition<IAzureResourceDefinition>(group.Key, batch)))
+                        .ToList(); // flatten 
+        }
+
+    /// <summary>
+        /// splits the "raw" batch according to max batch size configured
+        /// </summary>
+        private static List<List<ScrapeDefinition<IAzureResourceDefinition>>> SplitScrapeDefinitionBatch(List<ScrapeDefinition<IAzureResourceDefinition>> batchToSplit, int maxBatchSize) 
+        {
+            int numNewGroups = ((batchToSplit.Count - 1) / maxBatchSize) + 1;
+
+            return Enumerable.Range(0, numNewGroups)
+                .Select(i => batchToSplit.Skip(i * maxBatchSize).Take(maxBatchSize).ToList())
+                .ToList();
+        }
+    }
+}

src/Promitor.Core.Scraping/Configuration/Model/AzureMetricConfiguration.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Text;
 
 namespace Promitor.Core.Scraping.Configuration.Model
 {
@@ -45,5 +46,29 @@ public class AzureMetricConfiguration
             }
             return Dimensions?.Any(dimension => dimension.Name.Equals(dimensionName, StringComparison.InvariantCultureIgnoreCase));
         }
+
+         // A unique string to represent this Azure metric and its configured dimensions
+        public string ToUniqueStringRepresentation()
+        {
+            StringBuilder sb = new StringBuilder();
+            sb.Append(MetricName);
+            if (Dimension != null) 
+            {
+                sb.Append('_');
+                sb.Append(Dimension.Name);
+            }
+            else if (Dimensions != null) 
+            {
+                foreach (var dimension in Dimensions)
+                {
+                    sb.Append('_');
+                    sb.Append(dimension.Name);
+                }
+            }
+            sb.Append($"_limit{Limit}");
+
+
+            return sb.ToString();
+        }
     }
 }

src/Promitor.Core.Scraping/Configuration/Model/Metrics/BatchScrapeDefinition.cs

@@ -0,0 +1,39 @@
+using System.Collections.Generic;
+using GuardNet;
+using Promitor.Core.Contracts;
+
+namespace Promitor.Core.Scraping.Configuration.Model.Metrics
+{
+    /// <summary>
+    /// Defines a batch of ScrapeDefinitions to be executed in a single request 
+    /// Scrape definitions within a batch should share
+    /// 1. The same resource type 
+    /// 2. The same Azure metric scrape target with identical dimensions
+    /// 3. The same time granularity 
+    /// 4. The same filters
+    /// </summary>
+    public class BatchScrapeDefinition<TResourceDefinition> where TResourceDefinition : class, IAzureResourceDefinition
+    {
+        /// <summary>
+        /// Creates a new instance of the <see cref="BatchScrapeDefinition{TResourceDefinition}"/> class.
+        /// </summary>
+        /// <param name="scrapeDefinitionBatchProperties">Shared Properties Among ScrapeDefinition's in the batch</param>
+        /// <param name="groupedScrapeDefinitions">Scape definitions in the batch</param>
+        public BatchScrapeDefinition(ScrapeDefinitionBatchProperties scrapeDefinitionBatchProperties, List<ScrapeDefinition<TResourceDefinition>> groupedScrapeDefinitions)
+        {
+            Guard.NotNull(groupedScrapeDefinitions, nameof(groupedScrapeDefinitions));
+            Guard.NotLessThan(groupedScrapeDefinitions.Count, 1, nameof(groupedScrapeDefinitions));
+            Guard.NotNull(scrapeDefinitionBatchProperties, nameof(scrapeDefinitionBatchProperties));
+
+            ScrapeDefinitionBatchProperties = scrapeDefinitionBatchProperties;
+            ScrapeDefinitions = groupedScrapeDefinitions;
+        }
+
+        /// <summary>
+        /// A batch of scrape job definitions to be executed as a single request 
+        /// </summary>
+        public List<ScrapeDefinition<TResourceDefinition>> ScrapeDefinitions { get; set; }
+
+        public ScrapeDefinitionBatchProperties ScrapeDefinitionBatchProperties { get; set; }
+    }
+}

src/Promitor.Core.Scraping/Configuration/Model/Metrics/ScrapeDefinition.cs

@@ -94,5 +94,16 @@ public ScrapeDefinition(
             }
             return AzureMetricConfiguration?.Aggregation?.Interval;
         }
+
+        public ScrapeDefinitionBatchProperties BuildScrapingBatchInfo() { 
+            return new ScrapeDefinitionBatchProperties(
+                this.AzureMetricConfiguration,
+                this.LogAnalyticsConfiguration,
+                this.PrometheusMetricDefinition,    
+                this.Resource.ResourceType,
+                this.Scraping,
+                this.SubscriptionId
+            ); 
+         }
     }
 }