[Discovery.KubernetesApi] Add Akka.Hosting extension methods

src/discovery/kubernetes/Akka.Discovery.KubernetesApi.Tests/AkkaHostingSpec.cs

@@ -0,0 +1,73 @@
+// -----------------------------------------------------------------------
+//  <copyright file="AkkaHostingSpec.cs" company="Akka.NET Project">
+//      Copyright (C) 2009-2022 Lightbend Inc. <http://www.lightbend.com>
+//      Copyright (C) 2013-2022 .NET Foundation <https://github.com/akkadotnet/akka.net>
+//  </copyright>
+// -----------------------------------------------------------------------
+
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Threading.Tasks;
+using Akka.Actor;
+using Akka.Actor.Setup;
+using Akka.Hosting;
+using FluentAssertions;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using Xunit;
+using Xunit.Sdk;
+
+namespace Akka.Discovery.KubernetesApi.Tests
+{
+    public class AkkaHostingSpec
+    {
+        [Fact(DisplayName = "AkkaConfigurationBuilder extension should inject proper HOCON and Setup")]
+        public async Task AkkaConfigurationBuilderTest()
+        {
+            var hostBuilder = new HostBuilder()
+                .ConfigureServices((context, services) =>
+                {
+                    services.AddAkka("test", (builder, provider) =>
+                    {
+                        builder
+                            .WithKubernetesDiscovery(new KubernetesDiscoverySetup
+                            {
+                                PodNamespace = "underTest",
+                            });
+
+                        var setup = ExtractSetup<KubernetesDiscoverySetup>(builder);
+                        setup.Should().NotBeNull();
+                        setup.PodNamespace.Should().Be("underTest");
+                        builder.Configuration.HasValue.Should().BeTrue();
+                        builder.Configuration.Value.GetString("akka.discovery.method").Should().Be("kubernetes-api");
+                    });
+                });
+
+            using (var host = hostBuilder.Build())
+            {
+                await host.StartAsync();
+
+                var system = host.Services.GetRequiredService<ActorSystem>();
+
+                var settings = KubernetesDiscovery.Get(system).Settings;
+                settings.PodNamespace.Should().Be("underTest");
+
+                system.Settings.Config.GetString("akka.discovery.method").Should().Be("kubernetes-api");
+            }
+        }
+
+        private static T ExtractSetup<T>(AkkaConfigurationBuilder builder) where T : Setup
+        {
+            var type = builder.GetType();
+            var fieldInfo = type.GetField("Setups", BindingFlags.NonPublic | BindingFlags.Instance);
+            if (fieldInfo == null)
+                throw new XunitException("Could not found 'AkkaConfigurationBuilder.Setups' field, AkkaConfigurationBuilder internal API has changed");
+
+            var setups = (HashSet<Setup>) fieldInfo.GetValue(builder);
+            setups.Should().NotBeNull("'AkkaConfigurationBuilder.Setups' should exist and contains a value");
+            return (T) setups!.FirstOrDefault(s => s is KubernetesDiscoverySetup);
+        }
+
+    }
+}

src/discovery/kubernetes/Akka.Discovery.KubernetesApi.Tests/KubernetesDiscoverySettingsSpec.cs

@@ -53,27 +53,6 @@ public void EmptySettingsTest()
             empty.ContainerName.Should().Be(settings.ContainerName);
         }
 
-        [Fact(DisplayName = "Illegal pod-label-selector must throw")]
-        public void IllegalPodLabelSelectorTest()
-        {
-            var settings = KubernetesDiscoverySettings.Empty;
-
-            Invoking(() => settings.WithPodLabelSelector("={0}"))
-                .Should().ThrowExactly<ConfigurationException>();
-
-            Invoking(() => settings.WithPodLabelSelector("a="))
-                .Should().ThrowExactly<ConfigurationException>();
-
-            Invoking(() => settings.WithPodLabelSelector("a=={0}"))
-                .Should().ThrowExactly<ConfigurationException>();
-
-            Invoking(() => settings.WithPodLabelSelector("a{1}={0}"))
-                .Should().ThrowExactly<ConfigurationException>();
-
-            Invoking(() => settings.WithPodLabelSelector("a={0}b"))
-                .Should().ThrowExactly<ConfigurationException>();
-        }
-
         [Fact(DisplayName = "Settings With override must work")]
         public void WithOverrideTest()
         {

src/discovery/kubernetes/Akka.Discovery.KubernetesApi/Akka.Discovery.KubernetesApi.csproj

@@ -10,6 +10,7 @@
 
     <ItemGroup>
         <PackageReference Include="Akka.Discovery" Version="$(AkkaVersion)" />
+        <PackageReference Include="Akka.Hosting" Version="0.4.2" />
         <PackageReference Include="KubernetesClient" Version="$(KubernetesClientVersion)" />
     </ItemGroup>
 

src/discovery/kubernetes/Akka.Discovery.KubernetesApi/AkkaHostingExtensions.cs

@@ -0,0 +1,143 @@
+// -----------------------------------------------------------------------
+//  <copyright file="AkkaHostingExtensions.cs" company="Akka.NET Project">
+//      Copyright (C) 2009-2022 Lightbend Inc. <http://www.lightbend.com>
+//      Copyright (C) 2013-2022 .NET Foundation <https://github.com/akkadotnet/akka.net>
+//  </copyright>
+// -----------------------------------------------------------------------
+
+using System;
+using Akka.Actor;
+using Akka.Hosting;
+
+namespace Akka.Discovery.KubernetesApi
+{
+    public static class AkkaHostingExtensions
+    {
+        /// <summary>
+        ///     Adds Akka.Discovery.KubernetesApi support to the <see cref="ActorSystem"/>.
+        ///     Note that this only adds the discovery plugin, you will still need to add ClusterBootstrap for
+        ///     a complete solution.
+        /// </summary>
+        /// <param name="builder">
+        ///     The builder instance being configured.
+        /// </param>
+        /// <param name="podLabelSelector">
+        ///     <para>
+        ///         Optional. Pod label selector value to query pod API with. See the official Kubernetes documentation on 
+        ///         <a href="https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/#label-selectors">
+        ///         label selectors</a> for more information.
+        ///     </para>
+        ///     <b>Default</b>: "app={0}", where "{0}" will be replaced by
+        ///     <c>ClusterBootstrapSetup.ContactPointDiscovery.ServiceName</c> value.
+        /// </param>
+        /// <returns>
+        ///     The same <see cref="AkkaConfigurationBuilder"/> instance originally passed in.
+        /// </returns>
+        /// <example>
+        ///   <code>
+        ///     // In this code sample, the final label selector would be "app=testService".
+        ///     services.AddAkka("mySystem", builder => {
+        ///         builder
+        ///             .WithClustering()
+        ///             .WithClusterBootstrap(setup =>
+        ///             {
+        ///                 setup.ContactPointDiscovery.ServiceName = "testService";
+        ///             }, autoStart: true)
+        ///             .WithKubernetesDiscovery();
+        ///     }
+        ///   </code>
+        /// </example>
+        public static AkkaConfigurationBuilder WithKubernetesDiscovery(
+            this AkkaConfigurationBuilder builder,
+            string podLabelSelector = null)
+        {
+            return builder.WithKubernetesDiscovery(new KubernetesDiscoverySetup
+            {
+                PodLabelSelector = podLabelSelector
+            });
+        }
+
+        /// <summary>
+        ///     Adds Akka.Discovery.KubernetesApi support to the <see cref="ActorSystem"/>.
+        ///     Note that this only adds the discovery plugin, you will still need to add ClusterBootstrap for
+        ///     a complete solution.
+        /// </summary>
+        /// <param name="builder">
+        ///     The builder instance being configured.
+        /// </param>
+        /// <param name="configure">
+        ///     An action that modifies an <see cref="KubernetesDiscoverySetup"/> instance, used
+        ///     to configure Akka.Discovery.KubernetesApi.
+        /// </param>
+        /// <returns>
+        ///     The same <see cref="AkkaConfigurationBuilder"/> instance originally passed in.
+        /// </returns>
+        /// <example>
+        ///   <code>
+        ///     services.AddAkka("mySystem", builder => {
+        ///         builder
+        ///             .WithClustering()
+        ///             .WithClusterBootstrap(setup =>
+        ///             {
+        ///                 setup.ContactPointDiscovery.ServiceName = "testService";
+        ///             }, autoStart: true)
+        ///             .WithKubernetesDiscovery(setup => {
+        ///                 setup.PodNamespace = "my-cluster-namespace";
+        ///             });
+        ///     }
+        ///   </code>
+        /// </example>
+        public static AkkaConfigurationBuilder WithKubernetesDiscovery(
+            this AkkaConfigurationBuilder builder,
+            Action<KubernetesDiscoverySetup> configure)
+        {
+            var setup = new KubernetesDiscoverySetup();
+            configure(setup);
+            return builder.WithKubernetesDiscovery(setup);
+        }
+
+        /// <summary>
+        ///     Adds Akka.Discovery.KubernetesApi support to the <see cref="ActorSystem"/>.
+        ///     Note that this only adds the discovery plugin, you will still need to add ClusterBootstrap for
+        ///     a complete solution.
+        /// </summary>
+        /// <param name="builder">
+        ///     The builder instance being configured.
+        /// </param>
+        /// <param name="setup">
+        ///     The <see cref="KubernetesDiscoverySetup"/> instance used to configure Akka.Discovery.KubernetesApi.
+        /// </param>
+        /// <returns>
+        ///     The same <see cref="AkkaConfigurationBuilder"/> instance originally passed in.
+        /// </returns>
+        /// <example>
+        ///   <code>
+        ///     services.AddAkka("mySystem", builder => {
+        ///         builder
+        ///             .WithClustering()
+        ///             .WithClusterBootstrap(setup =>
+        ///             {
+        ///                 setup.ContactPointDiscovery.ServiceName = "testService";
+        ///             }, autoStart: true)
+        ///             .WithKubernetesDiscovery(new KubernetesDiscoverySetup {
+        ///                 PodNamespace = "my-cluster-namespace"
+        ///             });
+        ///     }
+        ///   </code>
+        /// </example>
+        public static AkkaConfigurationBuilder WithKubernetesDiscovery(
+            this AkkaConfigurationBuilder builder,
+            KubernetesDiscoverySetup setup)
+        {
+            builder.AddHocon("akka.discovery.method=kubernetes-api", HoconAddMode.Prepend);
+            builder.AddSetup(setup);
+
+            // Force start the module
+            builder.AddStartup((system, registry) =>
+            {
+                KubernetesDiscovery.Get(system);
+            });
+            return builder;
+        }
+    }
+}

src/discovery/kubernetes/Akka.Discovery.KubernetesApi/KubernetesDiscoverySettings.cs

@@ -5,9 +5,7 @@
 // </copyright>
 //-----------------------------------------------------------------------
 
-using System.Linq;
 using Akka.Actor;
-using Akka.Configuration;
 
 #nullable enable
 namespace Akka.Discovery.KubernetesApi
@@ -55,14 +53,6 @@ public static KubernetesDiscoverySettings Create(Configuration.Config config)
             PodNamespacePath = podNamespacePath;
             PodNamespace = podNamespace;
             PodDomain = podDomain;
-            if (!podLabelSelector.EndsWith("={0}") ||
-                podLabelSelector.StartsWith("=") ||
-                podLabelSelector.Count(c => c == '{') != 1 ||
-                podLabelSelector.Count(c => c == '}') != 1 ||
-                podLabelSelector.Count(c => c == '=') != 1)
-            {
-                throw new ConfigurationException("pod-label-selector value must be in the form of \"podLabel={0}\"");
-            }
             _podLabelSelector = podLabelSelector;
             RawIp = rawIp;
             ContainerName = string.IsNullOrWhiteSpace(containerName) ? null : containerName;