Restructure backend/endpoint config, config reload #9 (#42)

.editorconfig

@@ -231,7 +231,7 @@ csharp_using_directive_placement = outside_namespace:error
 
 # New-line options
 # https://docs.microsoft.com/en-us/visualstudio/ide/editorconfig-formatting-conventions?view=vs-2019#new-line-options
-csharp_new_line_before_open_brace = methods, properties, control_blocks, types
+csharp_new_line_before_open_brace = methods, properties, control_blocks, types, anonymous_methods, lambdas
 csharp_new_line_before_else = true
 csharp_new_line_before_catch = true
 csharp_new_line_before_finally = true

docs/config.md

@@ -133,6 +133,26 @@ Additional feedback: Why is it using arrays instead of objects? These items are
       },
 ```
 
+Update: The backend and endpoint layout has been modified to the following:
+```
+
+    "Backends": {
+      "backend1": {
+        "Endpoints": {
+          "backend1/endpoint1": {
+            "Address": "https://localhost:10000/"
+          }
+        }
+      },
+      "backend2": {
+        "Endpoints": {
+          "backend2/endpoint1": {
+            "Address": "https://localhost:10001/"
+          }
+        }
+      }
+    },
+```
 
 ## Config reloading
 
@@ -158,6 +178,10 @@ Config reload for proxy routes, backends, and endpoints already works. You edit
 
 Also, when a kestrel endpoint is modified or removed should existing connections on that endpoint be eagerly drained and closed, or should they be allowed to run a normal lifecycle? Kestrel does not currently track active connection per endpoint so additional tracking would be needed if we wanted to shut them down.
 
+Updates:
+
+The config reload code has been moved from the sample into the product assemblies.
+
 ## Augmenting config via code
 
 Some things are easier to do in code and we want to be able to support that while still pulling more transient data from config. [Kestrel](https://github.com/dotnet/aspnetcore/blob/aff01ebd7f82d641a4cfbd4a34954300311d9c2b/src/Servers/Kestrel/samples/SampleApp/Startup.cs#L138-L147) has a model where endpoints are named in config and then can be reference by name in code for additional configuration.

samples/ReverseProxy.Sample/Startup.cs

@@ -5,7 +5,6 @@
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.ReverseProxy.Core.Configuration.DependencyInjection;
-using Microsoft.ReverseProxy.Sample.Config;
 
 namespace Microsoft.ReverseProxy.Sample
 {
@@ -30,12 +29,7 @@ public Startup(IConfiguration configuration)
         public void ConfigureServices(IServiceCollection services)
         {
             services.AddControllers();
-            services.AddReverseProxy();
-
-            // The following 2 lines are all that we need to react to config changes on the fly.
-            // You can then change appsettings.json on disk and we will apply the new configs without a restart.
-            services.Configure<ProxyConfigRoot>(_configuration.GetSection("ReverseProxy"));
-            services.AddHostedService<ProxyConfigApplier>();
+            services.AddReverseProxy().LoadFromConfig(_configuration.GetSection("ReverseProxy"), reloadOnChange: true);
         }
 
         /// <summary>

samples/ReverseProxy.Sample/appsettings.Development.json

@@ -2,7 +2,7 @@
   "Logging": {
     "LogLevel": {
       "Default": "Debug",
-      "Microsoft": "Warning",
+      "Microsoft": "Debug",
       "Microsoft.Hosting.Lifetime": "Information"
     }
   }

samples/ReverseProxy.Sample/appsettings.json

@@ -15,32 +15,32 @@
     }
   },
   "ReverseProxy": {
-    "DiscoveryMechanism": "static",
-    "StaticDiscoveryOptions": {
-      "Backends": [
-        {
-          "BackendId": "backend1"
-        }
-      ],
-      "Endpoints": {
-        "backend1": [
-          {
-            "EndpointId": "backend1/endpoint1",
+    "Backends": {
+      "backend1": {
+        "Endpoints": {
+          "backend1/endpoint1": {
             "Address": "https://localhost:10000/"
           }
-        ]
+        }
       },
-      "Routes": [
-        {
-          "RouteId": "backend1/route1",
-          "BackendId": "backend1",
-          "Match": {
-            "Methods": [ "GET", "POST" ],
-            "Host": "localhost",
-            "Path": "/{**catchall}"
+      "backend2": {
+        "Endpoints": {
+          "backend2/endpoint1": {
+            "Address": "https://localhost:10001/"
           }
         }
-      ]
-    }
+      }
+    },
+    "Routes": [
+      {
+        "RouteId": "backend1/route1",
+        "BackendId": "backend1",
+        "Match": {
+          "Methods": [ "GET", "POST" ],
+          "Host": "localhost",
+          "Path": "/{**catchall}"
+        }
+      }
+    ]
   }
 }

src/ReverseProxy.Core/Abstractions/BackendDiscovery/Contract/Backend.cs

@@ -12,17 +12,8 @@ namespace Microsoft.ReverseProxy.Core.Abstractions
     /// by proxying to any endpoint within the matching backend,
     /// honoring load balancing and partitioning policies when applicable.
     /// </summary>
-    /// <remarks>
-    /// When proxying to Service Fabric services, a <see cref="Backend"/> will generally correspond to a Serice Fabric service instance,
-    /// and the backend endpoints correspond to the endpoints of the replicas of said service.
-    /// </remarks>
     public sealed class Backend : IDeepCloneable<Backend>
     {
-        /// <summary>
-        /// Unique identifier of this backend. No other backend may specify the same value.
-        /// </summary>
-        public string BackendId { get; set; }
-
         /// <summary>
         /// Circuit breaker options.
         /// </summary>
@@ -48,6 +39,11 @@ public sealed class Backend : IDeepCloneable<Backend>
         /// </summary>
         public HealthCheckOptions HealthCheckOptions { get; set; }
 
+        /// <summary>
+        /// The set of backend endpoints associated with this backend.
+        /// </summary>
+        public IDictionary<string, BackendEndpoint> Endpoints { get; private set; } = new Dictionary<string, BackendEndpoint>(StringComparer.Ordinal);
+
         /// <summary>
         /// Arbitrary key-value pairs that further describe this backend.
         /// </summary>
@@ -58,12 +54,12 @@ Backend IDeepCloneable<Backend>.DeepClone()
         {
             return new Backend
             {
-                BackendId = BackendId,
                 CircuitBreakerOptions = CircuitBreakerOptions?.DeepClone(),
                 QuotaOptions = QuotaOptions?.DeepClone(),
                 PartitioningOptions = PartitioningOptions?.DeepClone(),
                 LoadBalancingOptions = LoadBalancingOptions?.DeepClone(),
                 HealthCheckOptions = HealthCheckOptions?.DeepClone(),
+                Endpoints = Endpoints.DeepClone(StringComparer.Ordinal),
                 Metadata = Metadata?.DeepClone(StringComparer.Ordinal),
             };
         }

src/ReverseProxy.Core/Abstractions/BackendDiscovery/IBackendsRepo.cs

@@ -16,11 +16,11 @@ public interface IBackendsRepo
         /// <summary>
         /// Gets the current set of backends.
         /// </summary>
-        Task<IList<Backend>> GetBackendsAsync(CancellationToken cancellation);
+        Task<IDictionary<string, Backend>> GetBackendsAsync(CancellationToken cancellation);
 
         /// <summary>
         /// Sets the current set of backends.
         /// </summary>
-        Task SetBackendsAsync(IList<Backend> backends, CancellationToken cancellation);
+        Task SetBackendsAsync(IDictionary<string, Backend> backends, CancellationToken cancellation);
     }
 }

src/ReverseProxy.Core/Abstractions/BackendEndpointDiscovery/Contract/BackendEndpoint.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft Corporation.
+// Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
 using System;
@@ -11,11 +11,6 @@ namespace Microsoft.ReverseProxy.Core.Abstractions
     /// </summary>
     public sealed class BackendEndpoint : IDeepCloneable<BackendEndpoint>
     {
-        /// <summary>
-        /// Unique identifier of this endpoint. This must be globally unique.
-        /// </summary>
-        public string EndpointId { get; set; }
-
         /// <summary>
         /// Address of this endpoint. E.g. <c>https://127.0.0.1:123/abcd1234/</c>.
         /// </summary>
@@ -31,7 +26,6 @@ BackendEndpoint IDeepCloneable<BackendEndpoint>.DeepClone()
         {
             return new BackendEndpoint
             {
-                EndpointId = EndpointId,
                 Address = Address,
                 Metadata = Metadata?.DeepClone(StringComparer.Ordinal),
             };

src/ReverseProxy.Core/Configuration/DependencyInjection/BuilderExtensions/Core.cs

@@ -34,7 +34,6 @@ public static IReverseProxyBuilder AddMetrics(this IReverseProxyBuilder builder)
         public static IReverseProxyBuilder AddInMemoryRepos(this IReverseProxyBuilder builder)
         {
             builder.Services.AddSingleton<IBackendsRepo, InMemoryBackendsRepo>();
-            builder.Services.AddSingleton<IBackendEndpointsRepo, InMemoryEndpointsRepo>();
             builder.Services.AddSingleton<IRoutesRepo, InMemoryRoutesRepo>();
 
             return builder;

src/ReverseProxy.Core/Configuration/DependencyInjection/ReverseProxyServiceCollectionExtensions.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
+using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 
 namespace Microsoft.ReverseProxy.Core.Configuration.DependencyInjection
@@ -30,5 +31,21 @@ public static IReverseProxyBuilder AddReverseProxy(this IServiceCollection servi
 
             return builder;
         }
+
+        /// <summary>
+        /// Loads routes and endpoints from config.
+        /// </summary>
+        /// <param name="builder"></param>
+        /// <param name="config"></param>
+        /// <param name="reloadOnChange"></param>
+        /// <returns></returns>
+        public static IReverseProxyBuilder LoadFromConfig(this IReverseProxyBuilder builder, IConfiguration config, bool reloadOnChange = true)
+        {
+            builder.Services.Configure<ProxyConfigOptions>(config);
+            builder.Services.Configure<ProxyConfigOptions>(options => options.ReloadOnChange = reloadOnChange);
+            builder.Services.AddHostedService<ProxyConfigLoader>();
+
+            return builder;
+        }
     }
 }