From b078521f171727735ab4a33709b2cc88bb091fb2 Mon Sep 17 00:00:00 2001
From: "Chris Ross (ASP.NET)" <chrross@microsoft.com>
Date: Wed, 8 Aug 2018 16:34:04 -0700
Subject: [PATCH] Hold open the nginx dynamic port

---
 .../Deployers/NginxDeployer.cs                | 28 +++++++++++++++++--
 1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/src/Microsoft.AspNetCore.Server.IntegrationTesting/Deployers/NginxDeployer.cs b/src/Microsoft.AspNetCore.Server.IntegrationTesting/Deployers/NginxDeployer.cs
index 30451f9e88..262ff80ce8 100644
--- a/src/Microsoft.AspNetCore.Server.IntegrationTesting/Deployers/NginxDeployer.cs
+++ b/src/Microsoft.AspNetCore.Server.IntegrationTesting/Deployers/NginxDeployer.cs
@@ -4,7 +4,9 @@
 using System;
 using System.Diagnostics;
 using System.IO;
+using System.Net;
 using System.Net.Http;
+using System.Net.Sockets;
 using System.Runtime.InteropServices;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Server.IntegrationTesting.Common;
@@ -19,6 +21,7 @@ namespace Microsoft.AspNetCore.Server.IntegrationTesting
     {
         private string _configFile;
         private readonly int _waitTime = (int)TimeSpan.FromSeconds(30).TotalMilliseconds;
+        private Socket _portSelector;
 
         public NginxDeployer(DeploymentParameters deploymentParameters, ILoggerFactory loggerFactory)
             : base(deploymentParameters, loggerFactory)
@@ -30,10 +33,29 @@ namespace Microsoft.AspNetCore.Server.IntegrationTesting
             using (Logger.BeginScope("Deploy"))
             {
                 _configFile = Path.GetTempFileName();
+
                 var uri = string.IsNullOrEmpty(DeploymentParameters.ApplicationBaseUriHint) ?
-                    TestUriHelper.BuildTestUri(ServerType.Nginx) :
+                    new Uri("http://localhost:0") :
                     new Uri(DeploymentParameters.ApplicationBaseUriHint);
 
+                if (uri.Port == 0)
+                {
+                    var builder = new UriBuilder(uri);
+                    if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+                    {
+                        // This works with nginx 1.9.1 and later using the reuseport flag, available on Ubuntu 16.04.
+                        // Keep it open so nobody else claims the port
+                        _portSelector = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
+                        _portSelector.Bind(new IPEndPoint(IPAddress.Loopback, 0));
+                        builder.Port = ((IPEndPoint)_portSelector.LocalEndPoint).Port;
+                    }
+                    else
+                    {
+                        builder.Port = TestPortHelper.GetNextPort();
+                    }
+                    uri = builder.Uri;
+                }
+
                 var redirectUri = TestUriHelper.BuildTestUri(ServerType.Nginx);
 
                 if (DeploymentParameters.RuntimeFlavor == RuntimeFlavor.CoreClr
@@ -122,7 +144,7 @@ namespace Microsoft.AspNetCore.Server.IntegrationTesting
                     .Replace("[user]", userName)
                     .Replace("[errorlog]", errorLog)
                     .Replace("[accesslog]", accessLog)
-                    .Replace("[listenPort]", originalUri.Port.ToString())
+                    .Replace("[listenPort]", originalUri.Port.ToString() + (_portSelector != null ? " reuseport" : ""))
                     .Replace("[redirectUri]", redirectUri)
                     .Replace("[pidFile]", pidFile);
                 Logger.LogDebug("Using PID file: {pidFile}", pidFile);
@@ -199,6 +221,8 @@ namespace Microsoft.AspNetCore.Server.IntegrationTesting
                     File.Delete(_configFile);
                 }
 
+                _portSelector?.Dispose();
+
                 base.Dispose();
             }
         }