Augment config from code #9

samples/ReverseProxy.Sample/Startup.cs

@@ -1,11 +1,14 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
+using System;
 using System.Net;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Caching.Memory;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.ReverseProxy.Core.Abstractions;
 
 namespace Microsoft.ReverseProxy.Sample
 {
@@ -30,7 +33,39 @@ public Startup(IConfiguration configuration)
         public void ConfigureServices(IServiceCollection services)
         {
             services.AddControllers();
-            services.AddReverseProxy().LoadFromConfig(_configuration.GetSection("ReverseProxy"), reloadOnChange: true);
+            services.AddMemoryCache();
+            services.AddReverseProxy()
+                .LoadFromConfig(_configuration.GetSection("ReverseProxy"), reloadOnChange: true)
+                .ConfigureBackendDefaults((id, backend) =>
+                {
+                    backend.HealthCheckOptions ??= new HealthCheckOptions();
+                    // How to use custom metadata to configure backends
+                    if (backend.Metadata?.TryGetValue("CustomHealth", out var customHealth) ?? false
+                        && string.Equals(customHealth, "true", StringComparison.OrdinalIgnoreCase))
+                    {
+                        backend.HealthCheckOptions.Enabled = true;
+                    }
+                })
+                .ConfigureBackend("backend1", backend =>
+                {
+                    backend.HealthCheckOptions.Enabled = false;
+                })
+                .ConfigureRouteDefaults(route =>
+                {
+                    // Do not let config based routes take priority over code based routes.
+                    // Lower numbers are higher priority.
+                    if (route.Priority.HasValue && route.Priority.Value < 0)
+                    {
+                        route.Priority = 0;
+                    }
+                })
+                // If I need services as part of the config:
+                .ConfigureRoute<IMemoryCache>("route1", (route, cache) =>
+                {
+                    var value = cache.Get<int>("key");
+                    route.Priority = value;
+                })
+                ;
         }
 
         /// <summary>

samples/ReverseProxy.Sample/appsettings.json

@@ -20,6 +20,9 @@
         "LoadBalancing": {
           "Mode": "Random"
         },
+        "Metadata": {
+          "CustomHealth": "true"
+        },
         "Endpoints": {
           "backend1/endpoint1": {
             "Address": "https://localhost:10000/"
@@ -39,7 +42,7 @@
     },
     "Routes": [
       {
-        "RouteId": "backend1/route1",
+        "RouteId": "route1",
         "BackendId": "backend1",
         "Match": {
           "Methods": [ "GET", "POST" ],

src/ReverseProxy.Core/Abstractions/Config/IConfigErrorReporter.cs

@@ -1,6 +1,8 @@
-// Copyright (c) Microsoft Corporation.
+// Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
+using System;
+
 namespace Microsoft.ReverseProxy.Core.Abstractions
 {
     /// <summary>
@@ -12,5 +14,10 @@ public interface IConfigErrorReporter
         /// Reports a configuration error.
         /// </summary>
         void ReportError(string code, string itemId, string message);
+
+        /// <summary>
+        /// Reports a configuration error.
+        /// </summary>
+        void ReportError(string code, string itemId, string message, Exception ex);
     }
 }

src/ReverseProxy.Core/Abstractions/RouteDiscovery/Contract/ProxyRoute.cs

@@ -20,7 +20,7 @@ public sealed class ProxyRoute : IDeepCloneable<ProxyRoute>
         public ProxyMatch Match { get; private set; } = new ProxyMatch();
 
         /// <summary>
-        /// Optionally, a priority value for this route. Routes with higher numbers take precedence over lower numbers.
+        /// Optionally, a priority value for this route. Routes with lower numbers take precedence over higher numbers.
         /// </summary>
         public int? Priority { get; set; }
 

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

@@ -1,9 +1,13 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
+using System;
+using System.Collections.Generic;
 using Microsoft.Extensions.Configuration;
+using Microsoft.ReverseProxy.Core.Abstractions;
 using Microsoft.ReverseProxy.Core.Configuration;
 using Microsoft.ReverseProxy.Core.Configuration.DependencyInjection;
+using Microsoft.ReverseProxy.Core.Service;
 
 namespace Microsoft.Extensions.DependencyInjection
 {
@@ -48,5 +52,233 @@ public static IReverseProxyBuilder LoadFromConfig(this IReverseProxyBuilder buil
 
             return builder;
         }
+
+        /// <summary>
+        /// Provides a configuration action that runs on all routes each time the configuration is generated. This can be called more than once and
+        /// the Actions are run in the given order.
+        /// </summary>
+        /// <param name="builder"></param>
+        /// <param name="configure"></param>
+        /// <returns></returns>
+        public static IReverseProxyBuilder ConfigureRouteDefaults(this IReverseProxyBuilder builder, Action<ProxyRoute> configure)
+        {
+            if (configure is null)
+            {
+                throw new ArgumentNullException(nameof(configure));
+            }
+
+            builder.Services.Configure<DynamicConfigBuilderOptions>(options =>
+            {
+                options.RouteDefaultConfigs.Add(configure);
+            });
+
+            return builder;
+        }
+
+        /// <summary>
+        /// Provides a configuration action that runs on all routes each time the configuration is generated. This can be called more than once and
+        /// the Actions are run in the given order.
+        /// </summary>
+        /// <typeparam name="TService">TService: A service resolved from the IServiceProvider for use when configuring routes. If you need multiple services
+        /// then specify IServiceProvider and resolve them directly.</typeparam>
+        /// <param name="builder"></param>
+        /// <param name="configure"></param>
+        /// <returns></returns>
+        public static IReverseProxyBuilder ConfigureRouteDefaults<TService>(this IReverseProxyBuilder builder, Action<ProxyRoute, TService> configure) where TService : class
+        {
+            if (configure is null)
+            {
+                throw new ArgumentNullException(nameof(configure));
+            }
+
+            builder.Services.AddOptions<DynamicConfigBuilderOptions>().Configure<TService>((options, service) =>
+            {
+                options.RouteDefaultConfigs.Add(route => configure(route, service));
+            });
+
+            return builder;
+        }
+
+        /// <summary>
+        /// Provides a configuration action that runs on the named route each time the configuration is generated. This can be called more than once
+        /// per route and the Actions are run in the given order. These are applied after any default configuration Actions.
+        /// </summary>
+        /// <param name="builder"></param>
+        /// <param name="routeId"></param>
+        /// <param name="configure"></param>
+        /// <returns></returns>
+        public static IReverseProxyBuilder ConfigureRoute(this IReverseProxyBuilder builder, string routeId, Action<ProxyRoute> configure)
+        {
+            if (routeId is null)
+            {
+                throw new ArgumentNullException(nameof(routeId));
+            }
+
+            if (configure is null)
+            {
+                throw new ArgumentNullException(nameof(configure));
+            }
+
+            builder.Services.Configure<DynamicConfigBuilderOptions>(options =>
+            {
+                if (!options.RouteConfigs.TryGetValue(routeId, out var configs))
+                {
+                    configs = new List<Action<ProxyRoute>>(1);
+                    options.RouteConfigs[routeId] = configs;
+                }
+                configs.Add(configure);
+            });
+
+            return builder;
+        }
+
+        /// <summary>
+        /// Provides a configuration action that runs on the named route each time the configuration is generated. This can be called more than once
+        /// per route and the Actions are run in the given order. These are applied after any default configuration Actions.
+        /// </summary>
+        /// <typeparam name="TService">TService: A service resolved from the IServiceProvider for use when configuring this route. If you need multiple
+        /// services then specify IServiceProvider and resolve them directly.</typeparam>
+        /// <param name="builder"></param>
+        /// <param name="routeId"></param>
+        /// <param name="configure"></param>
+        /// <returns></returns>
+        public static IReverseProxyBuilder ConfigureRoute<TService>(this IReverseProxyBuilder builder, string routeId, Action<ProxyRoute, TService> configure) where TService : class
+        {
+            if (routeId is null)
+            {
+                throw new ArgumentNullException(nameof(routeId));
+            }
+
+            if (configure is null)
+            {
+                throw new ArgumentNullException(nameof(configure));
+            }
+
+            builder.Services.AddOptions<DynamicConfigBuilderOptions>().Configure<TService>((options, service) =>
+            {
+                if (!options.RouteConfigs.TryGetValue(routeId, out var configs))
+                {
+                    configs = new List<Action<ProxyRoute>>(1);
+                    options.RouteConfigs[routeId] = configs;
+                }
+                configs.Add(route => configure(route, service));
+            });
+
+            return builder;
+        }
+
+        /// <summary>
+        /// Provides a configuration action that runs on all backends each time the configuration is generated. This can be called more than once and
+        /// the Actions are run in the given order.
+        /// </summary>
+        /// <param name="builder"></param>
+        /// <param name="configure"></param>
+        /// <returns></returns>
+        public static IReverseProxyBuilder ConfigureBackendDefaults(this IReverseProxyBuilder builder, Action<string, Backend> configure)
+        {
+            if (configure is null)
+            {
+                throw new ArgumentNullException(nameof(configure));
+            }
+
+            builder.Services.Configure<DynamicConfigBuilderOptions>(options =>
+            {
+                options.BackendDefaultConfigs.Add(configure);
+            });
+
+            return builder;
+        }
+
+        /// <summary>
+        /// Provides a configuration action that runs on all backends each time the configuration is generated. This can be called more than once and
+        /// the Actions are run in the given order.
+        /// </summary>
+        /// <typeparam name="TService">TService: A service resolved from the IServiceProvider for use when configuring backends. If you need multiple
+        /// services then specify IServiceProvider and resolve them directly.</typeparam>
+        /// <param name="builder"></param>
+        /// <param name="configure"></param>
+        /// <returns></returns>
+        public static IReverseProxyBuilder ConfigureBackendDefaults<TService>(this IReverseProxyBuilder builder, Action<string, Backend, TService> configure) where TService : class
+        {
+            if (configure is null)
+            {
+                throw new ArgumentNullException(nameof(configure));
+            }
+
+            builder.Services.AddOptions<DynamicConfigBuilderOptions>().Configure<TService>((options, service) =>
+            {
+                options.BackendDefaultConfigs.Add((backendId, backend) => configure(backendId, backend, service));
+            });
+
+            return builder;
+        }
+
+        /// <summary>
+        /// Provides a configuration action that runs on the named backend each time the configuration is generated. This can be called more than once
+        /// per backend and the Actions are run in the given order. These are applied after any default configuration Actions.
+        /// </summary>
+        /// <param name="builder"></param>
+        /// <param name="backendId"></param>
+        /// <param name="configure"></param>
+        /// <returns></returns>
+        public static IReverseProxyBuilder ConfigureBackend(this IReverseProxyBuilder builder, string backendId, Action<Backend> configure)
+        {
+            if (backendId is null)
+            {
+                throw new ArgumentNullException(nameof(backendId));
+            }
+
+            if (configure is null)
+            {
+                throw new ArgumentNullException(nameof(configure));
+            }
+
+            builder.Services.Configure<DynamicConfigBuilderOptions>(options =>
+            {
+                if (!options.BackendConfigs.TryGetValue(backendId, out var configs))
+                {
+                    configs = new List<Action<Backend>>(1);
+                    options.BackendConfigs[backendId] = configs;
+                }
+                configs.Add(configure);
+            });
+
+            return builder;
+        }
+
+        /// <summary>
+        /// Provides a configuration action that runs on the named backend each time the configuration is generated. This can be called more than once
+        /// per backend and the Actions are run in the given order. These are applied after any default configuration Actions.
+        /// </summary>
+        /// <typeparam name="TService">TService: A service resolved from the IServiceProvider for use when configuring this backend. If you need multiple
+        /// services then specify IServiceProvider and resolve them directly.</typeparam>
+        /// <param name="builder"></param>
+        /// <param name="backendId"></param>
+        /// <param name="configure"></param>
+        /// <returns></returns>
+        public static IReverseProxyBuilder ConfigureBackend<TService>(this IReverseProxyBuilder builder, string backendId, Action<Backend, TService> configure) where TService : class
+        {
+            if (backendId is null)
+            {
+                throw new ArgumentNullException(nameof(backendId));
+            }
+
+            if (configure is null)
+            {
+                throw new ArgumentNullException(nameof(configure));
+            }
+
+            builder.Services.AddOptions<DynamicConfigBuilderOptions>().Configure<TService>((options, service) =>
+            {
+                if (!options.BackendConfigs.TryGetValue(backendId, out var configs))
+                {
+                    configs = new List<Action<Backend>>(1);
+                    options.BackendConfigs[backendId] = configs;
+                }
+                configs.Add(backend => configure(backend, service));
+            });
+
+            return builder;
+        }
     }
 }

src/ReverseProxy.Core/Configuration/ProxyConfigLoader.cs

@@ -112,6 +112,11 @@ public void ReportError(string code, string itemId, string message)
             {
                 Log.ConfigError(_logger, code, itemId, message);
             }
+
+            public void ReportError(string code, string itemId, string message, Exception ex)
+            {
+                Log.ConfigError(_logger, ex, code, itemId, message);
+            }
         }
 
 
@@ -142,6 +147,11 @@ public static void ConfigError(ILogger logger, string code, string itemId, strin
                 _configError(logger, code, itemId, message, null);
             }
 
+            public static void ConfigError(ILogger logger, Exception ex, string code, string itemId, string message)
+            {
+                _configError(logger, code, itemId, message, ex);
+            }
+
             public static void ApplyProxyConfig(ILogger logger)
             {
                 _applyProxyConfig(logger, null);

src/ReverseProxy.Core/Service/Config/ConfigErrors.cs

@@ -21,5 +21,8 @@ internal static class ConfigErrors
         internal const string ParsedRouteRuleMultipleHostMatchers = "ParsedRoute_RuleMultipleHostMatchers";
         internal const string ParsedRouteRuleMultiplePathMatchers = "ParsedRoute_RuleMultiplePathMatchers";
         internal const string ParsedRouteRuleInvalidMatcher = "ParsedRoute_RuleInvalidMatcher";
+
+        internal const string ConfigBuilderBackendException = "ConfigBuilder_BackendException";
+        internal const string ConfigBuilderRouteException = "ConfigBuilder_RouteException";
     }
 }