add downstream service name finder (#1188)

Author: Mantas Audickas

src/Ocelot/DependencyInjection/OcelotBuilder.cs

@@ -108,6 +108,7 @@ public OcelotBuilder(IServiceCollection services, IConfiguration configurationRo
             Services.TryAddSingleton<IDownstreamPathPlaceholderReplacer, DownstreamTemplatePathPlaceholderReplacer>();
             Services.AddSingleton<IDownstreamRouteProvider, DownstreamRouteFinder>();
             Services.AddSingleton<IDownstreamRouteProvider, DownstreamRouteCreator>();
+            Services.TryAddSingleton<IDownstreamServiceFinder, DownstreamServiceFinder>();
             Services.TryAddSingleton<IDownstreamRouteProviderFactory, DownstreamRouteProviderFactory>();
             Services.TryAddSingleton<IHttpRequester, HttpClientHttpRequester>();
             Services.TryAddSingleton<IHttpResponder, HttpContextResponder>();

src/Ocelot/DownstreamRouteFinder/Finder/DownstreamRouteCreator.cs

@@ -14,17 +14,19 @@
     public class DownstreamRouteCreator : IDownstreamRouteProvider
     {
         private readonly IQoSOptionsCreator _qoSOptionsCreator;
+        private readonly IDownstreamServiceFinder _serviceFinder;
         private readonly ConcurrentDictionary<string, OkResponse<DownstreamRoute>> _cache;
 
-        public DownstreamRouteCreator(IQoSOptionsCreator qoSOptionsCreator)
+        public DownstreamRouteCreator(IQoSOptionsCreator qoSOptionsCreator, IDownstreamServiceFinder serviceFinder)
         {
             _qoSOptionsCreator = qoSOptionsCreator;
+            _serviceFinder = serviceFinder;
             _cache = new ConcurrentDictionary<string, OkResponse<DownstreamRoute>>();
         }
 
         public Response<DownstreamRoute> Get(string upstreamUrlPath, string upstreamQueryString, string upstreamHttpMethod, IInternalConfiguration configuration, string upstreamHost)
         {
-            var serviceName = GetServiceName(upstreamUrlPath);
+            var serviceName = _serviceFinder.GetServiceName(upstreamUrlPath, upstreamQueryString, upstreamHttpMethod, upstreamHost, configuration);
 
             var downstreamPath = GetDownstreamPath(upstreamUrlPath);
 
@@ -108,19 +110,6 @@ private static string GetDownstreamPath(string upstreamUrlPath)
                 .Substring(upstreamUrlPath.IndexOf('/', 1));
         }
 
-        private static string GetServiceName(string upstreamUrlPath)
-        {
-            if (upstreamUrlPath.IndexOf('/', 1) == -1)
-            {
-                return upstreamUrlPath
-                    .Substring(1);
-            }
-
-            return upstreamUrlPath
-                .Substring(1, upstreamUrlPath.IndexOf('/', 1))
-                .TrimEnd('/');
-        }
-
         private string CreateLoadBalancerKey(string downstreamTemplatePath, string httpMethod, LoadBalancerOptions loadBalancerOptions)
         {
             if (!string.IsNullOrEmpty(loadBalancerOptions.Type) && !string.IsNullOrEmpty(loadBalancerOptions.Key) && loadBalancerOptions.Type == nameof(CookieStickySessions))

src/Ocelot/DownstreamRouteFinder/Finder/DownstreamServiceFinder.cs

@@ -0,0 +1,20 @@
+using Ocelot.Configuration;
+
+namespace Ocelot.DownstreamRouteFinder.Finder
+{
+    public class DownstreamServiceFinder: IDownstreamServiceFinder
+    {
+        public string GetServiceName(string upstreamUrlPath, string upstreamQueryString, string upstreamHttpMethod, string upstreamHost, IInternalConfiguration configuration)
+        {
+            if (upstreamUrlPath.IndexOf('/', 1) == -1)
+            {
+                return upstreamUrlPath
+                    .Substring(1);
+            }
+
+            return upstreamUrlPath
+                .Substring(1, upstreamUrlPath.IndexOf('/', 1))
+                .TrimEnd('/');
+        }
+    }
+}

src/Ocelot/DownstreamRouteFinder/Finder/IDownstreamServiceFinder.cs

@@ -0,0 +1,9 @@
+using Ocelot.Configuration;
+
+namespace Ocelot.DownstreamRouteFinder.Finder
+{
+    public interface IDownstreamServiceFinder
+    {
+        string GetServiceName(string upstreamUrlPath, string upstreamQueryString, string upstreamHttpMethod, string upstreamHost, IInternalConfiguration configuration);
+    }
+}

test/Ocelot.UnitTests/DownstreamRouteFinder/DownstreamRouteCreatorTests.cs

@@ -39,7 +39,7 @@ public DownstreamRouteCreatorTests()
             _qosOptionsCreator
                 .Setup(x => x.Create(It.IsAny<QoSOptions>(), It.IsAny<string>(), It.IsAny<List<string>>()))
                 .Returns(_qoSOptions);
-            _creator = new DownstreamRouteCreator(_qosOptionsCreator.Object);
+            _creator = new DownstreamRouteCreator(_qosOptionsCreator.Object, new DownstreamServiceFinder());
         }
 
         [Fact]

test/Ocelot.UnitTests/DownstreamRouteFinder/DownstreamRouteProviderFactoryTests.cs

@@ -30,6 +30,7 @@ public DownstreamRouteProviderFactoryTests()
             services.AddSingleton<IQoSOptionsCreator, QoSOptionsCreator>();
             services.AddSingleton<IDownstreamRouteProvider, DownstreamRouteFinder>();
             services.AddSingleton<IDownstreamRouteProvider, DownstreamRouteCreator>();
+            services.AddSingleton<IDownstreamServiceFinder, DownstreamServiceFinder>();
             var provider = services.BuildServiceProvider();
             _logger = new Mock<IOcelotLogger>();
             _loggerFactory = new Mock<IOcelotLoggerFactory>();

test/Ocelot.UnitTests/DownstreamRouteFinder/DownstreamServiceFinderTests.cs

@@ -0,0 +1,36 @@
+using Ocelot.DownstreamRouteFinder.Finder;
+using Xunit;
+
+namespace Ocelot.UnitTests.DownstreamRouteFinder
+{
+    public class DownstreamServiceFinderTests
+    {
+        private readonly DownstreamServiceFinder _serviceFinder;
+
+        public DownstreamServiceFinderTests()
+        {
+            _serviceFinder = new DownstreamServiceFinder();
+        }
+
+        [Fact]
+        public void should_return_empty_when_without_path()
+        {
+            var serviceName = _serviceFinder.GetServiceName("/");
+            Assert.Equal("", serviceName);
+        }
+
+        [Fact]
+        public void should_return_node_name_when_single_node()
+        {
+            var serviceName = _serviceFinder.GetServiceName("/service-name");
+            Assert.Equal("service-name", serviceName);
+        }
+
+        [Fact]
+        public void should_return_first_node_name_when_multiple_nodes()
+        {
+            var serviceName = _serviceFinder.GetServiceName("/service-name/some/longer/path");
+            Assert.Equal("service-name", serviceName);
+        }
+    }
+}