Rate limit

src/Ocelot/Configuration/Builder/ReRouteBuilder.cs

@@ -29,10 +29,12 @@ public class ReRouteBuilder
         private ServiceProviderConfiguraion _serviceProviderConfiguraion;
         private bool _useQos;
         private QoSOptions _qosOptions;
+        public bool _enableRateLimiting;
+        public RateLimitOptions _rateLimitOptions;
 
         public ReRouteBuilder WithLoadBalancer(string loadBalancer)
         {
-            _loadBalancer = loadBalancer;
+          _loadBalancer = loadBalancer;
             return this;
         }
 
@@ -161,6 +163,19 @@ public ReRouteBuilder WithAuthenticationOptions(AuthenticationOptions authentica
             return this;
         }
 
+        public ReRouteBuilder WithEnableRateLimiting(bool input)
+        {
+            _enableRateLimiting = input;
+            return this;
+        }
+
+        public ReRouteBuilder WithRateLimitOptions(RateLimitOptions input)
+        {
+            _rateLimitOptions = input;
+            return this;
+        }
+
+
         public ReRoute Build()
         {
             return new ReRoute(
@@ -185,7 +200,9 @@ public ReRoute Build()
                 _loadBalancerKey, 
                 _serviceProviderConfiguraion, 
                 _useQos, 
-                _qosOptions);
+                _qosOptions,
+                _enableRateLimiting,
+                _rateLimitOptions);
         }
     }
 }

src/Ocelot/Configuration/Creator/FileOcelotConfigurationCreator.cs

@@ -109,13 +109,17 @@ private async Task<ReRoute> SetUpReRoute(FileReRoute fileReRoute, FileGlobalConf
             var authOptionsForRoute = BuildAuthenticationOptions(fileReRoute);
 
             var claimsToHeaders = BuildAddThingsToRequest(fileReRoute.AddHeadersToRequest);
- 
+
             var claimsToClaims = BuildAddThingsToRequest(fileReRoute.AddClaimsToRequest);
 
             var claimsToQueries = BuildAddThingsToRequest(fileReRoute.AddQueriesToRequest);
 
             var qosOptions = BuildQoSOptions(fileReRoute);
 
+            var enableRateLimiting = IsEnableRateLimiting(fileReRoute);
+
+            var rateLimitOption = BuildRateLimitOptions(fileReRoute, globalConfiguration, enableRateLimiting);
+
             var reRoute = new ReRouteBuilder()
                 .WithDownstreamPathTemplate(fileReRoute.DownstreamPathTemplate)
                 .WithUpstreamPathTemplate(fileReRoute.UpstreamPathTemplate)
@@ -139,13 +143,34 @@ private async Task<ReRoute> SetUpReRoute(FileReRoute fileReRoute, FileGlobalConf
                 .WithServiceProviderConfiguraion(serviceProviderConfiguration)
                 .WithIsQos(isQos)
                 .WithQosOptions(qosOptions)
-                .Build();   
-
+                .WithEnableRateLimiting(enableRateLimiting)
+                .WithRateLimitOptions(rateLimitOption)
+                .Build();
             await SetupLoadBalancer(reRoute);
             SetupQosProvider(reRoute);
             return reRoute;
         }
 
+        private static RateLimitOptions BuildRateLimitOptions(FileReRoute fileReRoute, FileGlobalConfiguration globalConfiguration, bool enableRateLimiting)
+        {
+            RateLimitOptions rateLimitOption = null;
+            if (enableRateLimiting)
+            {
+                rateLimitOption = new RateLimitOptions(enableRateLimiting, globalConfiguration.RateLimitOptions.ClientIdHeader,
+                   fileReRoute.RateLimitOptions.ClientWhitelist, globalConfiguration.RateLimitOptions.DisableRateLimitHeaders,
+                   globalConfiguration.RateLimitOptions.QuotaExceededMessage, globalConfiguration.RateLimitOptions.RateLimitCounterPrefix,
+                   new RateLimitRule(fileReRoute.RateLimitOptions.Period, TimeSpan.FromSeconds(fileReRoute.RateLimitOptions.PeriodTimespan), fileReRoute.RateLimitOptions.Limit)
+                   , globalConfiguration.RateLimitOptions.HttpStatusCode);
+            }
+
+            return rateLimitOption;
+        }
+
+        private static bool IsEnableRateLimiting(FileReRoute fileReRoute)
+        {
+            return (fileReRoute.RateLimitOptions != null && fileReRoute.RateLimitOptions.EnableRateLimiting) ? true : false;
+        }
+
         private QoSOptions BuildQoSOptions(FileReRoute fileReRoute)
         {
             return new QoSOptionsBuilder()

src/Ocelot/Configuration/File/FileGlobalConfiguration.cs

@@ -5,8 +5,12 @@ public class FileGlobalConfiguration
         public FileGlobalConfiguration()
         {
             ServiceDiscoveryProvider = new FileServiceDiscoveryProvider();
+            RateLimitOptions = new FileRateLimitOptions();
         }
         public string RequestIdKey { get; set; }
+
         public FileServiceDiscoveryProvider ServiceDiscoveryProvider {get;set;}
+
+        public FileRateLimitOptions RateLimitOptions { get; set; }
     }
 }

src/Ocelot/Configuration/File/FileRateLimitOptions.cs

@@ -0,0 +1,39 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Ocelot.Configuration.File
+{
+    public class FileRateLimitOptions
+    {
+        /// <summary>
+        /// Gets or sets the HTTP header that holds the client identifier, by default is X-ClientId
+        /// </summary>
+        public string ClientIdHeader { get; set; } = "ClientId";
+
+        /// <summary>
+        /// Gets or sets a value that will be used as a formatter for the QuotaExceeded response message.
+        /// If none specified the default will be: 
+        /// API calls quota exceeded! maximum admitted {0} per {1}
+        /// </summary>
+        public string QuotaExceededMessage { get; set; }
+
+        /// <summary>
+        /// Gets or sets the counter prefix, used to compose the rate limit counter cache key
+        /// </summary>
+        public string RateLimitCounterPrefix { get; set; } = "ocelot";
+
+        /// <summary>
+        /// Disables X-Rate-Limit and Rety-After headers
+        /// </summary>
+        public bool DisableRateLimitHeaders { get; set; }
+
+        /// <summary>
+        /// Gets or sets the HTTP Status code returned when rate limiting occurs, by default value is set to 429 (Too Many Requests)
+        /// </summary>
+        public int HttpStatusCode { get;  set; } = 429;
+    }
+
+
+}

src/Ocelot/Configuration/File/FileRateLimitRule.cs

@@ -0,0 +1,34 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Ocelot.Configuration.File
+{
+
+    public class FileRateLimitRule
+    {
+        public FileRateLimitRule()
+        {
+            ClientWhitelist = new List<string>();
+        }
+
+        public List<string> ClientWhitelist { get; set; }
+
+        /// <summary>
+        /// Enables endpoint rate limiting based URL path and HTTP verb
+        /// </summary>
+        public bool EnableRateLimiting { get; set; }
+
+        /// <summary>
+        /// Rate limit period as in 1s, 1m, 1h
+        /// </summary>
+        public string Period { get; set; }
+
+        public double PeriodTimespan { get; set; }
+        /// <summary>
+        /// Maximum number of requests that a client can make in a defined period
+        /// </summary>
+        public long Limit { get; set; }
+    }
+}

src/Ocelot/Configuration/File/FileReRoute.cs

@@ -13,6 +13,7 @@ public FileReRoute()
             AuthenticationOptions = new FileAuthenticationOptions();
             FileCacheOptions = new FileCacheOptions();
             QoSOptions = new FileQoSOptions();
+            RateLimitOptions = new FileRateLimitRule();
         }
 
         public string DownstreamPathTemplate { get; set; }
@@ -32,5 +33,6 @@ public FileReRoute()
         public int DownstreamPort { get; set; }
         public FileQoSOptions QoSOptions { get; set; }
         public string LoadBalancer {get;set;}
+        public FileRateLimitRule RateLimitOptions { get; set; }
     }
 }

src/Ocelot/Configuration/RateLimitOptions.cs

@@ -0,0 +1,83 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Ocelot.Configuration
+{
+    /// <summary>
+    /// RateLimit Options
+    /// </summary>
+    public class RateLimitOptions
+    {
+        public RateLimitOptions(bool enbleRateLimiting, string clientIdHeader, List<string> clientWhitelist,bool disableRateLimitHeaders,
+            string quotaExceededMessage, string rateLimitCounterPrefix, RateLimitRule rateLimitRule, int httpStatusCode)
+        {
+            EnableRateLimiting = enbleRateLimiting;
+            ClientIdHeader = clientIdHeader;
+            ClientWhitelist = clientWhitelist?? new List<string>();
+            DisableRateLimitHeaders = disableRateLimitHeaders;
+            QuotaExceededMessage = quotaExceededMessage;
+            RateLimitCounterPrefix = rateLimitCounterPrefix;
+            RateLimitRule = rateLimitRule;
+            HttpStatusCode = httpStatusCode;
+        }
+
+        public RateLimitRule RateLimitRule { get;  private set; }
+
+        public List<string> ClientWhitelist { get; private set; }
+
+        /// <summary>
+        /// Gets or sets the HTTP header that holds the client identifier, by default is X-ClientId
+        /// </summary>
+        public string ClientIdHeader { get; private set; }  
+
+        /// <summary>
+        /// Gets or sets the HTTP Status code returned when rate limiting occurs, by default value is set to 429 (Too Many Requests)
+        /// </summary>
+        public int HttpStatusCode { get; private set; } 
+
+        /// <summary>
+        /// Gets or sets a value that will be used as a formatter for the QuotaExceeded response message.
+        /// If none specified the default will be: 
+        /// API calls quota exceeded! maximum admitted {0} per {1}
+        /// </summary>
+        public string QuotaExceededMessage { get; private set; }
+
+        /// <summary>
+        /// Gets or sets the counter prefix, used to compose the rate limit counter cache key
+        /// </summary>
+        public string RateLimitCounterPrefix { get; private set; }  
+
+        /// <summary>
+        /// Enables endpoint rate limiting based URL path and HTTP verb
+        /// </summary>
+        public bool EnableRateLimiting { get; private set; }
+
+        /// <summary>
+        /// Disables X-Rate-Limit and Rety-After headers
+        /// </summary>
+        public bool DisableRateLimitHeaders { get; private set; }
+    }
+
+    public class RateLimitRule
+    {
+        public RateLimitRule(string period, TimeSpan periodTimespan, long limit)
+        {
+            Period = period;
+            PeriodTimespan = periodTimespan;
+            Limit = limit;
+        }
+
+        /// <summary>
+        /// Rate limit period as in 1s, 1m, 1h,1d
+        /// </summary>
+        public string Period { get; private set; }
+
+        public TimeSpan PeriodTimespan { get; private set; }
+        /// <summary>
+        /// Maximum number of requests that a client can make in a defined period
+        /// </summary>
+        public long Limit { get; private set; }
+    }
+}

src/Ocelot/Configuration/ReRoute.cs

@@ -28,7 +28,9 @@ public ReRoute(PathTemplate downstreamPathTemplate,
             string reRouteKey, 
             ServiceProviderConfiguraion serviceProviderConfiguraion,
             bool isQos,
-            QoSOptions qos)
+            QoSOptions qos,
+            bool enableRateLimit,
+            RateLimitOptions ratelimitOptions)
         {
             ReRouteKey = reRouteKey;
             ServiceProviderConfiguraion = serviceProviderConfiguraion;
@@ -55,6 +57,8 @@ public ReRoute(PathTemplate downstreamPathTemplate,
                 DownstreamScheme = downstreamScheme;
             IsQos = isQos;
             QosOptions = qos;
+            EnableEndpointRateLimiting = enableRateLimit;
+            RateLimitOptions = ratelimitOptions;
         }
 
         public string ReRouteKey {get;private set;}
@@ -79,5 +83,7 @@ public ReRoute(PathTemplate downstreamPathTemplate,
         public string DownstreamHost { get; private set; }
         public int DownstreamPort { get; private set; }
         public ServiceProviderConfiguraion ServiceProviderConfiguraion { get; private set; }
+        public bool EnableEndpointRateLimiting { get; private set; }
+        public RateLimitOptions RateLimitOptions { get; private set; }
     }
 }

src/Ocelot/DependencyInjection/ServiceCollectionExtensions.cs

@@ -31,6 +31,7 @@
 using Ocelot.Requester.QoS;
 using Ocelot.Responder;
 using Ocelot.ServiceDiscovery;
+using Ocelot.RateLimit;
 
 namespace Ocelot.DependencyInjection
 {
@@ -87,12 +88,13 @@ public static IServiceCollection AddOcelot(this IServiceCollection services)
             services.AddSingleton<IErrorsToHttpStatusCodeMapper, ErrorsToHttpStatusCodeMapper>();
             services.AddSingleton<IAuthenticationHandlerFactory, AuthenticationHandlerFactory>();
             services.AddSingleton<IAuthenticationHandlerCreator, AuthenticationHandlerCreator>();
+            services.AddSingleton<IRateLimitCounterHandler, MemoryCacheRateLimitCounterHandler>();
 
             // see this for why we register this as singleton http://stackoverflow.com/questions/37371264/invalidoperationexception-unable-to-resolve-service-for-type-microsoft-aspnetc
             // could maybe use a scoped data repository
             services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
             services.AddScoped<IRequestScopedDataRepository, HttpDataRepository>();
-
+            services.AddMemoryCache();
             return services;
         }
     }

src/Ocelot/Middleware/OcelotMiddlewareExtensions.cs

@@ -11,6 +11,7 @@
 using Ocelot.Requester.Middleware;
 using Ocelot.RequestId.Middleware;
 using Ocelot.Responder.Middleware;
+using Ocelot.RateLimit.Middleware;
 
 namespace Ocelot.Middleware
 {
@@ -57,6 +58,9 @@ public static IApplicationBuilder UseOcelot(this IApplicationBuilder builder, Oc
             // Then we get the downstream route information
             builder.UseDownstreamRouteFinderMiddleware();
 
+            // We check whether the request is ratelimit, and if there is no continue processing
+            builder.UseRateLimiting();
+
             // Now we can look for the requestId
             builder.UseRequestIdMiddleware();
 

src/Ocelot/RateLimit/ClientRateLimitProcessor.cs

@@ -0,0 +1,37 @@
+using Microsoft.AspNetCore.Http;
+using Ocelot.Configuration;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Ocelot.RateLimit
+{
+    public class ClientRateLimitProcessor
+    {
+        private readonly IRateLimitCounterHandler _counterHandler;
+        private readonly RateLimitCore _core;
+
+        public ClientRateLimitProcessor(IRateLimitCounterHandler counterHandler)
+        {
+            _counterHandler = counterHandler;
+            _core = new RateLimitCore(_counterHandler);
+        }
+
+        public RateLimitCounter ProcessRequest(ClientRequestIdentity requestIdentity, RateLimitOptions option)
+        {
+            return _core.ProcessRequest(requestIdentity, option);
+        }
+
+        public string RetryAfterFrom(DateTime timestamp, RateLimitRule rule)
+        {
+            return _core.RetryAfterFrom(timestamp, rule);
+        }
+
+        public RateLimitHeaders GetRateLimitHeaders(HttpContext context, ClientRequestIdentity requestIdentity, RateLimitOptions option)
+        {
+            return _core.GetRateLimitHeaders(context, requestIdentity, option);
+        }
+
+    }
+}