Scaler apis

build/common.props

@@ -1,8 +1,8 @@
 <Project>
   <PropertyGroup>
     <!-- Packages can have independent versions and only increment when released -->
-    <Version>3.0.36$(VersionSuffix)</Version>
-    <HostStorageVersion>5.0.0-beta.2$(VersionSuffix)</HostStorageVersion>
+    <Version>3.0.37$(VersionSuffix)</Version>
+    <HostStorageVersion>5.0.0-beta.3$(VersionSuffix)</HostStorageVersion>
     <LoggingVersion>4.0.3$(VersionSuffix)</LoggingVersion>
 
     <TargetFramework>netstandard2.0</TargetFramework>

src/Microsoft.Azure.WebJobs.Host.Storage/StorageServiceCollectionExtensions.cs

@@ -31,8 +31,12 @@ public static void AddAzureStorageCoreServices(this IServiceCollection services)
             // Adds necessary Azure services to create clients
             services.AddAzureClientsCore();
 
-            services.TryAddSingleton<IAzureBlobStorageProvider, AzureStorageProvider>();
+            services.AddAzureStorageScaleServices();
+        }
 
+        public static void AddAzureStorageScaleServices(this IServiceCollection services)
+        {
+            services.TryAddSingleton<IAzureBlobStorageProvider, AzureStorageProvider>();
             services.AddSingleton<IConcurrencyStatusRepository, BlobStorageConcurrencyStatusRepository>();
         }
 

src/Microsoft.Azure.WebJobs.Host/Constants.cs

@@ -15,5 +15,6 @@ internal static class Constants
         public const string AzureWebsiteInstanceId = "WEBSITE_INSTANCE_ID";
         public const string AzureWebsiteContainerName = "CONTAINER_NAME";
         public const string DateTimeFormatString = "yyyy'-'MM'-'dd'T'HH':'mm':'ss'.'fffK";
+        public const string HostingConfigSectionName = "HostingConfig";
     }
 }

src/Microsoft.Azure.WebJobs.Host/Hosting/WebJobsHostBuilderExtensions.cs

@@ -4,12 +4,17 @@
 using System;
 using System.Linq;
 using Microsoft.Azure.WebJobs;
+using Microsoft.Azure.WebJobs.Host;
+using Microsoft.Azure.WebJobs.Host.Config;
+using Microsoft.Azure.WebJobs.Host.Executors;
+using Microsoft.Azure.WebJobs.Host.Scale;
 using Microsoft.Azure.WebJobs.Hosting;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.Configuration.EnvironmentVariables;
 using Microsoft.Extensions.Configuration.Json;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
+using Microsoft.FeatureManagement;
 
 namespace Microsoft.Extensions.Hosting
 {
@@ -135,6 +140,38 @@ public static IHostBuilder ConfigureWebJobs(this IHostBuilder builder, Action<Ho
             return builder;
         }
 
+        /// <summary>
+        /// Configures the specified <see cref="IHostBuilder"/> as a scale manager host.
+        /// </summary>
+        /// <param name="builder">The <see cref="IHostBuilder"/> to configure.</param>
+        /// <param name="configure">Configuration action to perform as part of service configuration.</param>
+        /// <param name="configureScaleOptions">Configuration action for <see cref="ScaleOptions"/>.</param>
+        /// <returns>The <see cref="IHostBuilder"/>.</returns>
+        public static IHostBuilder ConfigureWebJobsScale(this IHostBuilder builder,
+            Action<HostBuilderContext, IWebJobsBuilder> configure,
+            Action<ScaleOptions> configureScaleOptions)
+        {
+            builder.ConfigureServices((context, services) =>
+            {
+                WebJobsBuilder webJobsBuilder = new WebJobsBuilder(services);
+                configure?.Invoke(context, webJobsBuilder);
+
+                if (configureScaleOptions != null)
+                {
+                    services.Configure(configureScaleOptions);
+                }
+
+                services.AddFeatureManagement();
+                services.TryAddSingleton<IScaleMonitorManager, ScaleMonitorManager>();
+                services.TryAddSingleton<ITargetScalerManager, TargetScalerManager>();
+                services.TryAddSingleton<IScaleManager, ScaleManager>();
+                services.TryAddSingleton<IHostedService, ScaleMonitorService>();
+                services.TryAddSingleton<IPrimaryHostStateProvider>(new PrimaryHostStateProvider() { IsPrimary = true });
+            });
+
+            return builder;
+        }
+
         private static IConfigurationBuilder TryAddDefaultConfigurationSources(this IConfigurationBuilder config)
         {
             if (!config.Sources.OfType<JsonConfigurationSource>().Any(p => string.Equals(p.Path, "appsettings.json", StringComparison.OrdinalIgnoreCase)))

src/Microsoft.Azure.WebJobs.Host/Hosting/WebJobsServiceCollectionExtensions.cs

@@ -89,6 +89,7 @@ public static IWebJobsBuilder AddWebJobs(this IServiceCollection services, Actio
             services.TryAddSingleton<IDistributedLockManager, InMemoryDistributedLockManager>();
             services.TryAddSingleton<IScaleMonitorManager, ScaleMonitorManager>();
             services.TryAddSingleton<ITargetScalerManager, TargetScalerManager>();
+            services.TryAddSingleton<IScaleManager, ScaleManager>();
 
             services.AddSingleton<IPrimaryHostStateProvider, PrimaryHostStateProvider>();
             services.AddSingleton<IHostedService, PrimaryHostCoordinator>();

src/Microsoft.Azure.WebJobs.Host/Scale/IScaleManager.cs

@@ -0,0 +1,23 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Microsoft.Azure.WebJobs.Host.Scale
+{
+    /// <summary>
+    /// Provides scale status.
+    /// </summary>
+    public interface IScaleManager
+    {
+        /// <summary>
+        /// Gets the current scale status <see cref="ScaleStatus"> for all monitored functions.
+        /// </summary>
+        /// <param name="context">The <see cref="ScaleStatusContext"/>.</param>
+        /// <returns>The current <see cref="ScaleStatus"/>.</returns>
+        Task<ScaleStatus> GetScaleStatusAsync(ScaleStatusContext context);
+    }
+}

src/Microsoft.Azure.WebJobs.Host/Scale/IScaleMetricsRepository.cs

@@ -0,0 +1,28 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+using System.Threading.Tasks;
+
+namespace Microsoft.Azure.WebJobs.Host.Scale
+{
+    /// <summary>
+    /// Interface defining methods for reading/writing scale metrics to a persistent store.
+    /// </summary>
+    public interface IScaleMetricsRepository
+    {
+        /// <summary>
+        /// Persist the metrics for each monitor.
+        /// </summary>
+        /// <param name="monitorMetrics">The collection of metrics for each monitor.</param>
+        /// <returns>A task.</returns>
+        Task WriteMetricsAsync(IDictionary<IScaleMonitor, ScaleMetrics> monitorMetrics);
+
+        /// <summary>
+        /// Read the metrics.
+        /// </summary>
+        /// <param name="monitors">The current collection of monitors.</param>
+        /// <returns>Map of metrics per monitor.</returns>
+        Task<IDictionary<IScaleMonitor, IList<ScaleMetrics>>> ReadMetricsAsync(IEnumerable<IScaleMonitor> monitors);
+    }
+}

src/Microsoft.Azure.WebJobs.Host/Scale/IScalerProvider.cs

@@ -0,0 +1,27 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Microsoft.Azure.WebJobs.Host.Scale
+{
+    /// <summary>
+    /// Interface for providing scalers.
+    /// </summary>
+    public interface IScalerProvider
+    {
+        /// <summary>
+        /// Gets a collection of <see cref="IScaleMonitor"/>s.
+        /// </summary>
+        /// <returns>The <see cref="IScaleMonitor"/>s.</returns>
+        IEnumerable<IScaleMonitor> GetScaleMonitors();
+
+        /// <summary>
+        /// Gets a collection of <see cref="ITargetScaler"/>s.
+        /// </summary>
+        /// <returns>The <see cref="ITargetScaler"/>s.</returns>
+        IEnumerable<ITargetScaler> GetTargetScalers();
+    }
+}

src/Microsoft.Azure.WebJobs.Host/Scale/ITriggerMetadataProvider.cs

@@ -0,0 +1,19 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+
+namespace Microsoft.Azure.WebJobs.Host.Scale
+{
+    /// <summary>
+    /// Provides trigger metadata.
+    /// </summary>
+    public interface ITriggerMetadataProvider
+    {
+        /// <summary>
+        /// Gets the trigger metadata.
+        /// </summary>
+        /// <returns>The trigger metadata.</returns>
+        IEnumerable<TriggerMetadata> GetTriggerMetadata();
+    }
+}