fix(#449): Don't let Docker Desktop for Windows choose the random pub…

…lic host port

src/Testcontainers/Builders/NpipeEndpointAuthenticationProvider.cs

@@ -3,13 +3,19 @@
   using System;
   using System.Runtime.InteropServices;
   using DotNet.Testcontainers.Configurations;
+  using JetBrains.Annotations;
 
   /// <inheritdoc cref="IDockerRegistryAuthenticationProvider" />
   internal sealed class NpipeEndpointAuthenticationProvider : IDockerEndpointAuthenticationProvider
   {
 #pragma warning disable S1075
 
-    private static readonly Uri DockerEngine = new Uri("npipe://./pipe/docker_engine");
+    /// <summary>
+    /// Gets the named pipe Docker Engine endpoint.
+    /// </summary>
+    [PublicAPI]
+    public static Uri DockerEngine { get; }
+      = new Uri("npipe://./pipe/docker_engine");
 
 #pragma warning restore S1075
 

src/Testcontainers/Builders/UnixEndpointAuthenticationProvider.cs

@@ -3,11 +3,17 @@
   using System;
   using System.Runtime.InteropServices;
   using DotNet.Testcontainers.Configurations;
+  using JetBrains.Annotations;
 
   /// <inheritdoc cref="IDockerRegistryAuthenticationProvider" />
   internal sealed class UnixEndpointAuthenticationProvider : IDockerEndpointAuthenticationProvider
   {
-    private static readonly Uri DockerEngine = new Uri("unix:/var/run/docker.sock");
+    /// <summary>
+    /// Gets the Unix socket Docker Engine endpoint.
+    /// </summary>
+    [NotNull]
+    public static Uri DockerEngine { get; }
+      = new Uri("unix:/var/run/docker.sock");
 
     /// <inheritdoc />
     public bool IsApplicable()

src/Testcontainers/Configurations/TestcontainersSettings.cs

@@ -1,6 +1,10 @@
 namespace DotNet.Testcontainers.Configurations
 {
+  using System;
+  using System.Net;
+  using System.Net.Sockets;
   using System.Runtime.InteropServices;
+  using DotNet.Testcontainers.Builders;
   using DotNet.Testcontainers.Containers;
   using DotNet.Testcontainers.Images;
   using JetBrains.Annotations;
@@ -27,6 +31,19 @@ public static class TestcontainersSettings
     public static IDockerImage ResourceReaperImage { get; set; }
       = new DockerImage("ghcr.io/psanetra/ryuk:2021.12.20");
 
+    /// <summary>
+    /// Gets or sets the <see cref="ResourceReaper" /> public host port.
+    /// </summary>
+    /// <remarks>
+    /// The <see cref="ResourceReaper" /> might not be able to connect to Ryuk on Docker Desktop for Windows.
+    /// Assigning a random port might run into the excluded port range. The container starts, but we can not establish a TCP connection.
+    /// https://github.com/docker/for-win/issues/3171
+    /// https://github.com/docker/for-win/issues/11584
+    /// </remarks>
+    [PublicAPI]
+    public static Func<IDockerEndpointAuthenticationConfiguration, ushort> ResourceReaperPublicHostPort { get; set; }
+      = GetResourceReaperPublicHostPort;
+
     /// <summary>
     /// Gets or sets a prefix that applies to every image that is pulled from Docker Hub.
     /// </summary>
@@ -53,5 +70,23 @@ public static class TestcontainersSettings
     [NotNull]
     public static IOperatingSystem OS { get; set; }
       = RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? (IOperatingSystem)new Windows() : new Unix();
+
+    private static ushort GetResourceReaperPublicHostPort(IDockerEndpointAuthenticationConfiguration dockerEndpointAuthConfig)
+    {
+      // Let Docker choose the random public host port.
+      if (!NpipeEndpointAuthenticationProvider.DockerEngine.Equals(dockerEndpointAuthConfig.Endpoint))
+      {
+        return 0;
+      }
+
+      // Get the next available public host port. This might run in rare cases into a race-condition.
+      // It's still much more stable than letting Docker Desktop for Windows choose the port.
+      // !Attention!: This won't include Docker Engines exposed via TCP.
+      using (var socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
+      {
+        socket.Bind(new IPEndPoint(IPAddress.Loopback, 0));
+        return (ushort)((IPEndPoint)socket.LocalEndPoint).Port;
+      }
+    }
   }
 }

src/Testcontainers/Containers/ResourceReaper.cs

@@ -37,14 +37,16 @@ public sealed class ResourceReaper : IAsyncDisposable
 
     private ResourceReaper(Guid sessionId, IDockerEndpointAuthenticationConfiguration dockerEndpointAuthConfig, string ryukImage)
     {
+      dockerEndpointAuthConfig = dockerEndpointAuthConfig ?? TestcontainersSettings.OS.DockerEndpointAuthConfig;
+      ryukImage = ryukImage ?? TestcontainersSettings.ResourceReaperImage.FullName;
       this.resourceReaperContainer = new TestcontainersBuilder<TestcontainersContainer>()
         .WithName($"testcontainers-ryuk-{sessionId:D}")
-        .WithDockerEndpoint(dockerEndpointAuthConfig ?? TestcontainersSettings.OS.DockerEndpointAuthConfig)
-        .WithImage(ryukImage ?? TestcontainersSettings.ResourceReaperImage.FullName)
+        .WithDockerEndpoint(dockerEndpointAuthConfig)
+        .WithImage(ryukImage)
         .WithAutoRemove(true)
         .WithCleanUp(false)
         .WithExposedPort(RyukPort)
-        .WithPortBinding(RyukPort, true)
+        .WithPortBinding(TestcontainersSettings.ResourceReaperPublicHostPort.Invoke(dockerEndpointAuthConfig), RyukPort)
         .WithBindMount("/var/run/docker.sock", "/var/run/docker.sock", AccessMode.ReadOnly)
         .Build();
 

tests/Testcontainers.Tests/Unit/Configurations/DockerEndpointAuthenticationProviderTest.cs

@@ -21,7 +21,6 @@ public void GetDockerClientConfiguration(IDockerEndpointAuthenticationConfigurat
       }
     }
 
-
     private sealed class AuthConfigTestData : List<object[]>
     {
       public AuthConfigTestData()