Add Akka.Cluster.Tools.Client support (#66)

* Add Akka.Cluster.Tools.Client support

* Add settings unit tests

* Simplify ClusterClient setup

* Add some WithClusterClient overloads to give user options

src/Akka.Cluster.Hosting.Tests/ClusterClientSpecs.cs

@@ -0,0 +1,39 @@
+using System.Collections.Generic;
+using Akka.Actor;
+using Akka.Cluster.Tools.Client;
+using FluentAssertions;
+using FluentAssertions.Extensions;
+using Xunit;
+
+namespace Akka.Cluster.Hosting.Tests;
+
+public class ClusterClientSpecs
+{
+    [Fact(DisplayName = "ClusterClientReceptionistSettings should be set correctly")]
+    public void ClusterClientReceptionistSettingsSpec()
+    {
+        var config = AkkaClusterHostingExtensions.CreateReceptionistConfig("customName", "customRole")
+            .GetConfig("akka.cluster.client.receptionist");
+        var settings = ClusterReceptionistSettings.Create(config);
+
+        config.GetString("name").Should().Be("customName");
+        settings.Role.Should().Be("customRole");
+    }
+
+    [Fact(DisplayName = "ClusterClientSettings should be set correctly")]
+    public void ClusterClientSettingsSpec()
+    {
+        var contacts = new List<ActorPath>
+        {
+            ActorPath.Parse("akka.tcp://one@localhost:1111/system/receptionist"),
+            ActorPath.Parse("akka.tcp://two@localhost:1111/system/receptionist"),
+            ActorPath.Parse("akka.tcp://three@localhost:1111/system/receptionist"),
+        };
+
+        var settings = AkkaClusterHostingExtensions.CreateClusterClientSettings(
+            ClusterClientReceptionist.DefaultConfig(),
+            contacts);
+
+        settings.InitialContacts.Should().BeEquivalentTo(contacts);
+    }
+}

src/Akka.Cluster.Hosting/AkkaClusterHostingExtensions.cs

@@ -1,12 +1,18 @@
 using System;
 using System.Collections.Generic;
+using System.Collections.Immutable;
 using System.Linq;
+using System.Text;
+using System.Text.RegularExpressions;
 using Akka.Actor;
 using Akka.Cluster.Sharding;
 using Akka.Cluster.Tools.Client;
 using Akka.Cluster.Tools.PublishSubscribe;
 using Akka.Cluster.Tools.Singleton;
+using Akka.Configuration;
 using Akka.Hosting;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
 
 namespace Akka.Cluster.Hosting
 {
@@ -367,5 +373,129 @@ public static AkkaConfigurationBuilder WithSingletonProxy<TKey>(this AkkaConfigu
                 CreateAndRegisterSingletonProxy<TKey>(singletonName, singletonManagerPath, singletonProxySettings, system, registry);
             });
         }
+
+        /// <summary>
+        /// Configures a <see cref="ClusterClientReceptionist"/> for the <see cref="ActorSystem"/>
+        /// </summary>
+        /// <param name="builder">The builder instance being configured.</param>
+        /// <param name="name">Actor name of the ClusterReceptionist actor under the system path, by default it is /system/receptionist</param>
+        /// <param name="role">Checks that the receptionist only start on members tagged with this role. All members are used if empty.</param>
+        /// <returns>The same <see cref="AkkaConfigurationBuilder"/> instance originally passed in.</returns>
+        public static AkkaConfigurationBuilder WithClusterClientReceptionist(
+            this AkkaConfigurationBuilder builder,
+            string name = "receptionist",
+            string role = null)
+        {
+            builder.AddHocon(CreateReceptionistConfig(name, role), HoconAddMode.Prepend);
+            return builder;
+        }
+
+        internal static Config CreateReceptionistConfig(string name, string role)
+        {
+            const string root = "akka.cluster.client.receptionist.";
+
+            var sb = new StringBuilder()
+                .Append(root).Append("name:").AppendLine(QuoteIfNeeded(name));
+
+            if(!string.IsNullOrEmpty(role))
+                sb.Append(root).Append("role:").AppendLine(QuoteIfNeeded(role));
+
+            return ConfigurationFactory.ParseString(sb.ToString());
+        }
+
+        /// <summary>
+        /// Creates a <see cref="ClusterClient"/> and adds it to the <see cref="ActorRegistry"/> using the given
+        /// <see cref="TKey"/>.
+        /// </summary>
+        /// <param name="builder">The builder instance being configured.</param>
+        /// <param name="initialContacts"> <para>
+        /// List of <see cref="ClusterClientReceptionist"/> <see cref="ActorPath"/> that will be used as a seed
+        /// to discover all of the receptionists in the cluster.
+        /// </para>
+        /// <para>
+        /// This should look something like "akka.tcp://systemName@networkAddress:2552/system/receptionist"
+        /// </para></param>
+        /// <typeparam name="TKey">The key type to use for the <see cref="ActorRegistry"/>.</typeparam>
+        /// <returns>The same <see cref="AkkaConfigurationBuilder"/> instance originally passed in.</returns>
+        public static AkkaConfigurationBuilder WithClusterClient<TKey>(
+            this AkkaConfigurationBuilder builder,
+            IList<ActorPath> initialContacts)
+        {
+            if (initialContacts == null)
+                throw new ArgumentNullException(nameof(initialContacts));
+
+            if (initialContacts.Count < 1)
+                throw new ArgumentException("Must specify at least one initial contact", nameof(initialContacts));
+
+            return builder.WithActors((system, registry) =>
+            {
+                var clusterClient = system.ActorOf(ClusterClient.Props(
+                    CreateClusterClientSettings(system.Settings.Config, initialContacts)));
+                registry.TryRegister<TKey>(clusterClient);
+            });
+        }
+
+        /// <summary>
+        /// Creates a <see cref="ClusterClient"/> and adds it to the <see cref="ActorRegistry"/> using the given
+        /// <see cref="TKey"/>.
+        /// </summary>
+        /// <param name="builder">The builder instance being configured.</param>
+        /// <param name="initialContactAddresses"> <para>
+        /// List of node addresses where the <see cref="ClusterClientReceptionist"/> are located that will be used as seed
+        /// to discover all of the receptionists in the cluster.
+        /// </para>
+        /// <para>
+        /// This should look something like "akka.tcp://systemName@networkAddress:2552"
+        /// </para></param>
+        /// <param name="receptionistActorName">The name of the <see cref="ClusterClientReceptionist"/> actor.
+        /// Defaults to "receptionist"
+        /// </param>
+        /// <typeparam name="TKey">The key type to use for the <see cref="ActorRegistry"/>.</typeparam>
+        /// <returns>The same <see cref="AkkaConfigurationBuilder"/> instance originally passed in.</returns>
+        public static AkkaConfigurationBuilder WithClusterClient<TKey>(
+            this AkkaConfigurationBuilder builder,
+            IEnumerable<Address> initialContactAddresses,
+            string receptionistActorName = "receptionist")
+            => builder.WithClusterClient<TKey>(initialContactAddresses
+                .Select(address => new RootActorPath(address) / "system" / receptionistActorName)
+                .ToList());
+
+        /// <summary>
+        /// Creates a <see cref="ClusterClient"/> and adds it to the <see cref="ActorRegistry"/> using the given
+        /// <see cref="TKey"/>.
+        /// </summary>
+        /// <param name="builder">The builder instance being configured.</param>
+        /// <param name="initialContacts"> <para>
+        /// List of actor paths that will be used as a seed to discover all of the receptionists in the cluster.
+        /// </para>
+        /// <para>
+        /// This should look something like "akka.tcp://systemName@networkAddress:2552/system/receptionist"
+        /// </para></param>
+        /// <typeparam name="TKey">The key type to use for the <see cref="ActorRegistry"/>.</typeparam>
+        /// <returns>The same <see cref="AkkaConfigurationBuilder"/> instance originally passed in.</returns>
+        public static AkkaConfigurationBuilder WithClusterClient<TKey>(
+            this AkkaConfigurationBuilder builder,
+            IEnumerable<string> initialContacts)
+            => builder.WithClusterClient<TKey>(initialContacts.Select(ActorPath.Parse).ToList());
+
+        internal static ClusterClientSettings CreateClusterClientSettings(Config config, IEnumerable<ActorPath> initialContacts)
+        {
+            var clientConfig = config.GetConfig("akka.cluster.client");
+            return ClusterClientSettings.Create(clientConfig)
+                .WithInitialContacts(initialContacts.ToImmutableHashSet());
+        }
+
+        #region Helper functions
+
+        private static readonly Regex EscapeRegex = new Regex("[ \t:]{1}", RegexOptions.Compiled);
+
+        private static string QuoteIfNeeded(string text)
+        {
+            return text == null 
+                ? "" : EscapeRegex.IsMatch(text) 
+                    ? $"\"{text}\"" : text;
+        }
+
+        #endregion
     }
 }

src/Akka.Cluster.Hosting/Properties/FriendsOf.cs

@@ -0,0 +1,3 @@
+using System.Runtime.CompilerServices;
+
+[assembly: InternalsVisibleTo("Akka.Cluster.Hosting.Tests")]

src/Akka.Remote.Hosting.Tests/RemoteConfigurationSpecs.cs

@@ -29,4 +29,6 @@ public async Task AkkaRemoteShouldUsePublicHostnameCorrectly()
         // assert
         actorSystem.Provider.DefaultAddress.Host.Should().Be("localhost");
     }
+
+
 }