Ocelot/test/Ocelot.AcceptanceTests/LoadBalancerTests.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using Consul;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Ocelot.Configuration.File;
using Shouldly;
using TestStack.BDDfy;
using Xunit;

namespace Ocelot.AcceptanceTests
{
    public class LoadBalancerTests : IDisposable
    {
        private IWebHost _builderOne;
        private IWebHost _builderTwo;
        private readonly Steps _steps;
        private int _counterOne;
        private int _counterTwo;
        private static readonly object _syncLock = new object();

        public LoadBalancerTests()
        {
            _steps = new Steps();
        }

        [Fact]
        public void should_use_service_discovery_and_load_balance_request()
        {
            var downstreamServiceOneUrl = "http://localhost:50881";
            var downstreamServiceTwoUrl = "http://localhost:50882";

            var configuration = new FileConfiguration
            {
                ReRoutes = new List<FileReRoute>
                    {
                        new FileReRoute
                        {
                            DownstreamPathTemplate = "/",
                            DownstreamScheme = "http",
                            UpstreamPathTemplate = "/",
                            UpstreamHttpMethod = new List<string> { "Get" },
                            LoadBalancer = "LeastConnection",
                            DownstreamHostAndPorts = new List<FileHostAndPort>
                            {
                                new FileHostAndPort
                                {
                                    Host = "localhost",
                                    Port = 50881
                                },
                                new FileHostAndPort
                                {
                                    Host = "localhost",
                                    Port = 50882
                                }
                            }
                        }
                    },
                    GlobalConfiguration = new FileGlobalConfiguration()
                    {
                    }
            };

            this.Given(x => x.GivenProductServiceOneIsRunning(downstreamServiceOneUrl, 200))
                .And(x => x.GivenProductServiceTwoIsRunning(downstreamServiceTwoUrl, 200))
                .And(x => _steps.GivenThereIsAConfiguration(configuration))
                .And(x => _steps.GivenOcelotIsRunning())
                .When(x => _steps.WhenIGetUrlOnTheApiGatewayMultipleTimes("/", 50))
                .Then(x => x.ThenTheTwoServicesShouldHaveBeenCalledTimes(50))
                .And(x => x.ThenBothServicesCalledRealisticAmountOfTimes(24, 26))
                .BDDfy();
        }

        private void ThenOnlyOneServiceHasBeenCalled()
        {
            _counterOne.ShouldBe(10);
            _counterTwo.ShouldBe(0);
        }

         private void GivenIResetCounters()
        {
            _counterOne = 0;
            _counterTwo = 0;
        }

        private void ThenBothServicesCalledRealisticAmountOfTimes(int bottom, int top)
        {
            _counterOne.ShouldBeInRange(bottom, top);
            _counterOne.ShouldBeInRange(bottom, top);
        }

        private void ThenTheTwoServicesShouldHaveBeenCalledTimes(int expected)
        {
            var total = _counterOne + _counterTwo;
            total.ShouldBe(expected);
        }

        private void GivenProductServiceOneIsRunning(string url, int statusCode)
        {
            _builderOne = new WebHostBuilder()
                .UseUrls(url)
                .UseKestrel()
                .UseContentRoot(Directory.GetCurrentDirectory())
                .UseIISIntegration()
                .UseUrls(url)
                .Configure(app =>
                {
                    app.Run(async context =>
                    {
                        try
                        {
                            var response = string.Empty;
                            lock (_syncLock)
                            {
                                _counterOne++;
                                response = _counterOne.ToString();
                            }
                            context.Response.StatusCode = statusCode;
                            await context.Response.WriteAsync(response);
                        }
                        catch (System.Exception exception)
                        {
                            await context.Response.WriteAsync(exception.StackTrace);
                        }
                    });
                })
                .Build();

            _builderOne.Start();
        }

        private void GivenProductServiceTwoIsRunning(string url, int statusCode)
        {
            _builderTwo = new WebHostBuilder()
                .UseUrls(url)
                .UseKestrel()
                .UseContentRoot(Directory.GetCurrentDirectory())
                .UseIISIntegration()
                .UseUrls(url)
                .Configure(app =>
                {
                    app.Run(async context =>
                    {
                        try
                        {
                            var response = string.Empty;
                            lock (_syncLock)
                            {
                                _counterTwo++;
                                response = _counterTwo.ToString();
                            }
                            
                            context.Response.StatusCode = statusCode;
                            await context.Response.WriteAsync(response);
                        }
                        catch (System.Exception exception)
                        {
                            await context.Response.WriteAsync(exception.StackTrace);
                        }                   
                    });
                })
                .Build();

            _builderTwo.Start();
        }

        public void Dispose()
        {
            _builderOne?.Dispose();
            _builderTwo?.Dispose();
            _steps.Dispose();
        }
    }
}