plugged load balancer middleware into Ocelot pipeline, load balanced downstream host and port now used by url creator middleware

src/Ocelot/Configuration/Builder/ReRouteBuilder.cs

@@ -6,6 +6,7 @@ namespace Ocelot.Configuration.Builder
 {
     public class ReRouteBuilder
     {
+        private string _loadBalancerKey;
         private string _downstreamPathTemplate;
         private string _upstreamTemplate;
         private string _upstreamTemplatePattern;
@@ -199,6 +200,12 @@ namespace Ocelot.Configuration.Builder
             return this;
         }
 
+        public ReRouteBuilder WithLoadBalancerKey(string loadBalancerKey)
+        {
+            _loadBalancerKey = loadBalancerKey;
+            return this;
+        }
+
         public ReRoute Build()
         {
             return new ReRoute(new DownstreamPathTemplate(_downstreamPathTemplate), _upstreamTemplate, _upstreamHttpMethod, _upstreamTemplatePattern, 
@@ -206,7 +213,7 @@ namespace Ocelot.Configuration.Builder
                 _requireHttps, _additionalScopes, _scopeSecret), _configHeaderExtractorProperties, _claimToClaims, _routeClaimRequirement, 
                 _isAuthorised, _claimToQueries, _requestIdHeaderKey, _isCached, _fileCacheOptions, _serviceName, 
                 _useServiceDiscovery, _serviceDiscoveryAddress, _serviceDiscoveryProvider, _downstreamScheme, _loadBalancer,
-                _downstreamHost, _dsPort);
+                _downstreamHost, _dsPort, _loadBalancerKey);
         }
     }
 }

src/Ocelot/Configuration/Creator/FileOcelotConfigurationCreator.cs

@@ -104,6 +104,9 @@ namespace Ocelot.Configuration.Creator
                 && !string.IsNullOrEmpty(globalConfiguration?.ServiceDiscoveryProvider?.Address)
                 && !string.IsNullOrEmpty(globalConfiguration?.ServiceDiscoveryProvider?.Provider);
 
+            //note - not sure if this is the correct key, but this is probably the only unique key i can think of given my poor brain
+            var loadBalancerKey = $"{fileReRoute.UpstreamTemplate}{fileReRoute.UpstreamHttpMethod}";
+
             ReRoute reRoute;
             
             if (isAuthenticated)
@@ -124,7 +127,7 @@ namespace Ocelot.Configuration.Creator
                     requestIdKey, isCached, new CacheOptions(fileReRoute.FileCacheOptions.TtlSeconds),
                     fileReRoute.ServiceName, useServiceDiscovery, globalConfiguration?.ServiceDiscoveryProvider?.Provider,
                     globalConfiguration?.ServiceDiscoveryProvider?.Address, fileReRoute.DownstreamScheme, 
-                    fileReRoute.LoadBalancer, fileReRoute.DownstreamHost, fileReRoute.DownstreamPort);
+                    fileReRoute.LoadBalancer, fileReRoute.DownstreamHost, fileReRoute.DownstreamPort,loadBalancerKey);
             }
 
             reRoute = new ReRoute(new DownstreamPathTemplate(fileReRoute.DownstreamPathTemplate), fileReRoute.UpstreamTemplate, 
@@ -134,11 +137,10 @@ namespace Ocelot.Configuration.Creator
                     requestIdKey, isCached, new CacheOptions(fileReRoute.FileCacheOptions.TtlSeconds),
                     fileReRoute.ServiceName, useServiceDiscovery, globalConfiguration?.ServiceDiscoveryProvider?.Provider,
                     globalConfiguration?.ServiceDiscoveryProvider?.Address, fileReRoute.DownstreamScheme,
-                    fileReRoute.LoadBalancer, fileReRoute.DownstreamHost, fileReRoute.DownstreamPort);
+                    fileReRoute.LoadBalancer, fileReRoute.DownstreamHost, fileReRoute.DownstreamPort,loadBalancerKey);
 
             var loadBalancer = _loadBalanceFactory.Get(reRoute);
-            //todo - not sure if this is the correct key, but this is probably the only unique key i can think of
-            _loadBalancerHouse.Add($"{fileReRoute.UpstreamTemplate}{fileReRoute.UpstreamHttpMethod}", loadBalancer);
+            _loadBalancerHouse.Add(reRoute.LoadBalancerKey, loadBalancer);
             return reRoute;
         }
 

src/Ocelot/Configuration/ReRoute.cs

@@ -11,8 +11,9 @@ namespace Ocelot.Configuration
             List<ClaimToThing> claimsToClaims, Dictionary<string, string> routeClaimsRequirement, bool isAuthorised, List<ClaimToThing> claimsToQueries, 
             string requestIdKey, bool isCached, CacheOptions fileCacheOptions, string serviceName, bool useServiceDiscovery,
             string serviceDiscoveryProvider, string serviceDiscoveryAddress,
-            string downstreamScheme, string loadBalancer, string downstreamHost, int downstreamPort)
+            string downstreamScheme, string loadBalancer, string downstreamHost, int downstreamPort, string loadBalancerKey)
         {
+            LoadBalancerKey = loadBalancerKey;
             LoadBalancer = loadBalancer;
             DownstreamHost = downstreamHost;
             DownstreamPort = downstreamPort;
@@ -39,6 +40,7 @@ namespace Ocelot.Configuration
                 ServiceDiscoveryAddress = serviceDiscoveryAddress;
                 DownstreamScheme = downstreamScheme;
         }
+        public string LoadBalancerKey {get;private set;}
         public DownstreamPathTemplate DownstreamPathTemplate { get; private set; }
         public string UpstreamTemplate { get; private set; }
         public string UpstreamTemplatePattern { get; private set; }

src/Ocelot/DownstreamUrlCreator/Middleware/DownstreamUrlCreatorMiddleware.cs

@@ -47,15 +47,12 @@ namespace Ocelot.DownstreamUrlCreator.Middleware
 
             var dsScheme = DownstreamRoute.ReRoute.DownstreamScheme;
             
-            //todo - get this out of scoped data repo?
-            var dsHostAndPort = new HostAndPort(DownstreamRoute.ReRoute.DownstreamHost,
-                DownstreamRoute.ReRoute.DownstreamPort);
+            var dsHostAndPort = HostAndPort;
 
             var dsUrl = _urlBuilder.Build(dsPath.Data.Value, dsScheme, dsHostAndPort);
 
             if (dsUrl.IsError)
             {
-                //todo - release the lb connection?
                 _logger.LogDebug("IUrlBuilder returned an error, setting pipeline error");
 
                 SetPipelineError(dsUrl.Errors);
@@ -70,8 +67,6 @@ namespace Ocelot.DownstreamUrlCreator.Middleware
 
             await _next.Invoke(context);
 
-            //todo - release the lb connection?
-
             _logger.LogDebug("succesfully called next middleware");
         }
     }

src/Ocelot/LoadBalancer/Middleware/LoadBalancingMiddleware.cs

@@ -31,26 +31,32 @@ namespace Ocelot.LoadBalancer.Middleware
         {
             _logger.LogDebug("started calling load balancing middleware");
 
-            var loadBalancer = _loadBalancerHouse.Get($"{DownstreamRoute.ReRoute.UpstreamTemplate}{DownstreamRoute.ReRoute.UpstreamHttpMethod}");
-            //todo check reponse and return error
+            var loadBalancer = _loadBalancerHouse.Get(DownstreamRoute.ReRoute.LoadBalancerKey);
+            if(loadBalancer.IsError)
+            {
+                //set errors and return
+            }
 
-            var response = loadBalancer.Data.Lease();
-            //todo check reponse and return error
+            var hostAndPort = loadBalancer.Data.Lease();
+            if(hostAndPort.IsError)
+            {
+                //set errors and return
+            }
+
+            SetHostAndPortForThisRequest(hostAndPort.Data);
 
-            SetHostAndPortForThisRequest(response.Data);
             _logger.LogDebug("calling next middleware");
 
-            //todo - try next middleware if we get an exception make sure we release 
-            //the host and port? Not sure if this is the way to go but we shall see!
             try
             {
                 await _next.Invoke(context);
 
-                loadBalancer.Data.Release(response.Data);
+                loadBalancer.Data.Release(hostAndPort.Data);
             }
             catch (Exception)
             {
-                loadBalancer.Data.Release(response.Data);
+                loadBalancer.Data.Release(hostAndPort.Data);
+                 _logger.LogDebug("error calling next middleware, exception will be thrown to global handler");
                 throw;
             }
 

src/Ocelot/LoadBalancer/Middleware/LoadBalancingMiddlewareExtensions.cs

@@ -4,7 +4,7 @@ namespace Ocelot.LoadBalancer.Middleware
 {
  public static class LoadBalancingMiddlewareExtensions
     {
-        public static IApplicationBuilder UseLoadBalancingMiddlewareExtensions(this IApplicationBuilder builder)
+        public static IApplicationBuilder UseLoadBalancingMiddleware(this IApplicationBuilder builder)
         {
             return builder.UseMiddleware<LoadBalancingMiddleware>();
         }

src/Ocelot/Middleware/OcelotMiddlewareExtensions.cs

@@ -18,6 +18,7 @@ namespace Ocelot.Middleware
     using System.Threading.Tasks;
     using Authorisation.Middleware;
     using Microsoft.AspNetCore.Http;
+    using Ocelot.LoadBalancer.Middleware;
 
     public static class OcelotMiddlewareExtensions
     {
@@ -98,6 +99,9 @@ namespace Ocelot.Middleware
             // Now we can run any query string transformation logic
             builder.UseQueryStringBuilderMiddleware();
 
+            // Get the load balancer for this request
+            builder.UseLoadBalancingMiddleware();
+
             // This takes the downstream route we retrieved earlier and replaces any placeholders with the variables that should be used
             builder.UseDownstreamUrlCreatorMiddleware();
 

test/Ocelot.UnitTests/DownstreamUrlCreator/DownstreamUrlCreatorMiddlewareTests.cs

@@ -36,6 +36,7 @@ namespace Ocelot.UnitTests.DownstreamUrlCreator
         private HttpResponseMessage _result;
         private OkResponse<DownstreamPath> _downstreamPath;
         private OkResponse<DownstreamUrl> _downstreamUrl;
+        private HostAndPort _hostAndPort;
 
         public DownstreamUrlCreatorMiddlewareTests()
         {
@@ -69,14 +70,25 @@ namespace Ocelot.UnitTests.DownstreamUrlCreator
         [Fact]
         public void should_call_dependencies_correctly()
         {
+            var hostAndPort = new HostAndPort("127.0.0.1", 80);
+
             this.Given(x => x.GivenTheDownStreamRouteIs(new DownstreamRoute(new List<UrlPathPlaceholderNameAndValue>(), new ReRouteBuilder().WithDownstreamPathTemplate("any old string").Build())))
+                .And(x => x.GivenTheHostAndPortIs(hostAndPort))
                 .And(x => x.TheUrlReplacerReturns("/api/products/1"))
-                .And(x => x.TheUrlBuilderReturns("http://www.bbc.co.uk/api/products/1"))
+                .And(x => x.TheUrlBuilderReturns("http://127.0.0.1:80/api/products/1"))
                 .When(x => x.WhenICallTheMiddleware())
                 .Then(x => x.ThenTheScopedDataRepositoryIsCalledCorrectly())
                 .BDDfy();
         }
 
+        private void GivenTheHostAndPortIs(HostAndPort hostAndPort)
+        {
+            _hostAndPort = hostAndPort;
+            _scopedRepository
+                .Setup(x => x.Get<HostAndPort>("HostAndPort"))
+                .Returns(new OkResponse<HostAndPort>(_hostAndPort));
+        }
+
         private void TheUrlBuilderReturns(string dsUrl)
         {
             _downstreamUrl = new OkResponse<DownstreamUrl>(new DownstreamUrl(dsUrl));

test/Ocelot.UnitTests/LoadBalancer/LoadBalancerMiddlewareTests.cs

@@ -54,7 +54,7 @@ namespace Ocelot.UnitTests.LoadBalancer
               .UseUrls(_url)
               .Configure(app =>
               {
-                  app.UseLoadBalancingMiddlewareExtensions();
+                  app.UseLoadBalancingMiddleware();
               });
 
             _server = new TestServer(builder);