Port scala akka PR #26816 to Akka.NET (#4511)

* Port scala akka PR #26816 to Akka.NET

* Remove SynchronizationContext usage

* Use internal dispatcher in other part of Akka.NET, update documentation

* Port internal blocking dispatcher and default internal dispatcher for Akka.Stream

* Add circular dispatcher alias reference checking, unroll recursion

* Make ClusterSingletonManager and Proxy to use internal dispatchers

* Update API approver list

* Remove SynchronizationContext

* Clean up Pigeon.conf config file

Co-authored-by: Aaron Stannard <aaron@petabridge.com>

docs/articles/actors/dispatchers.md

@@ -70,6 +70,7 @@ system.ActorOf(Props.Create<MyActor>().WithDispatcher("my-dispatcher"), "my-acto
 Some dispatcher configurations are available out-of-the-box for convenience. You can use them during actor deployment, [as described above](#configuring-dispatchers).
 
 * **default-dispatcher** - A configuration that uses the [ThreadPoolDispatcher](#threadpooldispatcher). As the name says, this is the default dispatcher configuration used by the global dispatcher, and you don't need to define anything during deployment to use it.
+* **internal-dispatcher** - To protect the internal Actors that is spawned by the various Akka modules, a separate internal dispatcher is used by default.
 * **task-dispatcher** - A configuration that uses the [TaskDispatcher](#taskdispatcher).
 * **default-fork-join-dispatcher** - A configuration that uses the [ForkJoinDispatcher](#forkjoindispatcher).
 * **synchronized-dispatcher** - A configuration that uses the [SynchronizedDispatcher](#synchronizeddispatcher).
@@ -174,3 +175,10 @@ The following configuration keys are available for any dispatcher configuration:
 
 > [!NOTE]
 > The throughput-deadline-time is used as a *best effort*, not as a *hard limit*. This means that if a message takes more time than the deadline allows, Akka.NET won't interrupt the process. Instead it will wait for it to finish before giving turn to the next actor.
+
+## Dispatcher aliases
+
+When a dispatcher is looked up, and the given setting contains a string rather than a dispatcher config block, 
+the lookup will treat it as an alias, and follow that string to an alternate location for a dispatcher config.
+If the dispatcher config is referenced both through an alias and through the absolute path only one dispatcher will
+be used and shared among the two ids.

src/contrib/cluster/Akka.Cluster.Sharding/ClusterSharding.cs

@@ -262,7 +262,7 @@ public ClusterSharding(ExtendedActorSystem system)
             {
                 var guardianName = system.Settings.Config.GetString("akka.cluster.sharding.guardian-name");
                 var dispatcher = system.Settings.Config.GetString("akka.cluster.sharding.use-dispatcher");
-                if (string.IsNullOrEmpty(dispatcher)) dispatcher = Dispatchers.DefaultDispatcherId;
+                if (string.IsNullOrEmpty(dispatcher)) dispatcher = Dispatchers.InternalDispatcherId;
                 return system.SystemActorOf(Props.Create(() => new ClusterShardingGuardian()).WithDispatcher(dispatcher), guardianName);
             });
         }

src/contrib/cluster/Akka.Cluster.Sharding/reference.conf

@@ -137,7 +137,7 @@ akka.cluster.sharding {
   coordinator-singleton = "akka.cluster.singleton"
 
   # The id of the dispatcher to use for ClusterSharding actors.
-  # If not specified default dispatcher is used.
+  # If not specified, the internal dispatcher is used.
   # If specified you need to define the settings of the actual dispatcher.
   # This dispatcher for the entity actors is defined by the user provided
   # Props, i.e. this dispatcher is not used for the entity actors.

src/contrib/cluster/Akka.Cluster.Tools/Client/ClusterClientReceptionist.cs

@@ -133,7 +133,7 @@ private IActorRef CreateReceptionist()
             {
                 var name = _config.GetString("name");
                 var dispatcher = _config.GetString("use-dispatcher", null);
-                if (string.IsNullOrEmpty(dispatcher)) dispatcher = Dispatchers.DefaultDispatcherId;
+                if (string.IsNullOrEmpty(dispatcher)) dispatcher = Dispatchers.InternalDispatcherId;
 
                 // important to use var mediator here to activate it outside of ClusterReceptionist constructor
                 var mediator = PubSubMediator;

src/contrib/cluster/Akka.Cluster.Tools/Client/reference.conf

@@ -24,7 +24,7 @@ akka.cluster.client.receptionist {
   response-tunnel-receive-timeout = 30s
 
   # The id of the dispatcher to use for ClusterReceptionist actors. 
-  # If not specified default dispatcher is used.
+  # If not specified, the internal dispatcher is used.
   # If specified you need to define the settings of the actual dispatcher.
   use-dispatcher = ""
 

src/contrib/cluster/Akka.Cluster.Tools/PublishSubscribe/DistributedPubSub.cs

@@ -102,7 +102,7 @@ private IActorRef CreateMediator()
             var name = _system.Settings.Config.GetString("akka.cluster.pub-sub.name");
             var dispatcher = _system.Settings.Config.GetString("akka.cluster.pub-sub.use-dispatcher", null);
             if (string.IsNullOrEmpty(dispatcher))
-                dispatcher = Dispatchers.DefaultDispatcherId;
+                dispatcher = Dispatchers.InternalDispatcherId;
 
             return _system.SystemActorOf(
                 Props.Create(() => new DistributedPubSubMediator(_settings))

src/contrib/cluster/Akka.Cluster.Tools/PublishSubscribe/reference.conf

@@ -30,7 +30,7 @@ akka.cluster.pub-sub {
   max-delta-elements = 3000
 
   # The id of the dispatcher to use for DistributedPubSubMediator actors. 
-  # If not specified default dispatcher is used.
+  # If not specified, the internal dispatcher is used.
   # If specified you need to define the settings of the actual dispatcher.
   use-dispatcher = ""
 

src/contrib/cluster/Akka.Cluster.Tools/Singleton/ClusterSingletonManager.cs

@@ -14,6 +14,7 @@
 using Akka.Actor;
 using Akka.Configuration;
 using Akka.Coordination;
+using Akka.Dispatch;
 using Akka.Event;
 using Akka.Pattern;
 using Akka.Remote;
@@ -604,7 +605,9 @@ public static Props Props(Props singletonProps, ClusterSingletonManagerSettings
         /// <returns>TBD</returns>
         public static Props Props(Props singletonProps, object terminationMessage, ClusterSingletonManagerSettings settings)
         {
-            return Actor.Props.Create(() => new ClusterSingletonManager(singletonProps, terminationMessage, settings)).WithDeploy(Deploy.Local);
+            return Actor.Props.Create(() => new ClusterSingletonManager(singletonProps, terminationMessage, settings))
+                .WithDispatcher(Dispatchers.InternalDispatcherId)
+                .WithDeploy(Deploy.Local);
         }
 
         private readonly Props _singletonProps;

src/contrib/cluster/Akka.Cluster.Tools/Singleton/ClusterSingletonProxy.cs

@@ -11,6 +11,7 @@
 using System.Linq;
 using Akka.Actor;
 using Akka.Configuration;
+using Akka.Dispatch;
 using Akka.Event;
 
 namespace Akka.Cluster.Tools.Singleton
@@ -70,7 +71,9 @@ public static Config DefaultConfig()
         /// <returns>TBD</returns>
         public static Props Props(string singletonManagerPath, ClusterSingletonProxySettings settings)
         {
-            return Actor.Props.Create(() => new ClusterSingletonProxy(singletonManagerPath, settings)).WithDeploy(Deploy.Local);
+            return Actor.Props.Create(() => new ClusterSingletonProxy(singletonManagerPath, settings))
+                .WithDispatcher(Dispatchers.InternalDispatcherId)
+                .WithDeploy(Deploy.Local);
         }
 
         private readonly ClusterSingletonProxySettings _settings;

src/contrib/cluster/Akka.DistributedData/ReplicatorSettings.cs

@@ -43,7 +43,7 @@ public static ReplicatorSettings Create(Config config)
                 throw ConfigurationException.NullOrEmptyConfig<ReplicatorSettings>();
 
             var dispatcher = config.GetString("use-dispatcher", null);
-            if (string.IsNullOrEmpty(dispatcher)) dispatcher = Dispatchers.DefaultDispatcherId;
+            if (string.IsNullOrEmpty(dispatcher)) dispatcher = Dispatchers.InternalDispatcherId;
 
             var durableConfig = config.GetConfig("durable");
             var durableKeys = durableConfig.GetStringList("keys");
@@ -63,7 +63,7 @@ public static ReplicatorSettings Create(Config config)
                 {
                     throw new ArgumentException($"`akka.cluster.distributed-data.durable.store-actor-class` is set to an invalid class {durableStoreType}.");
                 }
-                durableStoreProps = Props.Create(durableStoreType, durableConfig).WithDispatcher(durableConfig.GetString("use-dispatcher"));
+                durableStoreProps = Props.Create(durableStoreType, durableConfig).WithDispatcher(dispatcher);
             }
 
             // TODO: This constructor call fails when these fields are not populated inside the Config object:
@@ -212,7 +212,7 @@ public static ReplicatorSettings Create(Config config)
         public ReplicatorSettings WithGossipInterval(TimeSpan gossipInterval) => Copy(gossipInterval: gossipInterval);
         public ReplicatorSettings WithNotifySubscribersInterval(TimeSpan notifySubscribersInterval) => Copy(notifySubscribersInterval: notifySubscribersInterval);
         public ReplicatorSettings WithMaxDeltaElements(int maxDeltaElements) => Copy(maxDeltaElements: maxDeltaElements);
-        public ReplicatorSettings WithDispatcher(string dispatcher) => Copy(dispatcher: string.IsNullOrEmpty(dispatcher) ? Dispatchers.DefaultDispatcherId : dispatcher);
+        public ReplicatorSettings WithDispatcher(string dispatcher) => Copy(dispatcher: string.IsNullOrEmpty(dispatcher) ? Dispatchers.InternalDispatcherId : dispatcher);
         public ReplicatorSettings WithPruning(TimeSpan pruningInterval, TimeSpan maxPruningDissemination) => 
             Copy(pruningInterval: pruningInterval, maxPruningDissemination: maxPruningDissemination);
         public ReplicatorSettings WithDurableKeys(IImmutableSet<string> durableKeys) => Copy(durableKeys: durableKeys);

src/contrib/cluster/Akka.DistributedData/reference.conf

@@ -26,8 +26,8 @@ akka.cluster.distributed-data {
   # the replicas. Next chunk will be transferred in next round of gossip.
   max-delta-elements = 1000
 
-  # The id of the dispatcher to use for Replicator actors. If not specified
-  # default dispatcher is used.
+  # The id of the dispatcher to use for Replicator actors. 
+  # If not specified, the internal dispatcher is used.
   # If specified you need to define the settings of the actual dispatcher.
   use-dispatcher = ""
 

src/core/Akka.API.Tests/CoreAPISpec.ApproveCore.approved.txt

@@ -1,5 +1,6 @@
 [assembly: System.Runtime.CompilerServices.InternalsVisibleToAttribute("Akka.Benchmarks")]
 [assembly: System.Runtime.CompilerServices.InternalsVisibleToAttribute("Akka.Cluster")]
+[assembly: System.Runtime.CompilerServices.InternalsVisibleToAttribute("Akka.Cluster.Sharding")]
 [assembly: System.Runtime.CompilerServices.InternalsVisibleToAttribute("Akka.Cluster.TestKit")]
 [assembly: System.Runtime.CompilerServices.InternalsVisibleToAttribute("Akka.Cluster.Tests")]
 [assembly: System.Runtime.CompilerServices.InternalsVisibleToAttribute("Akka.Cluster.Tests.MultiNode")]
@@ -1841,12 +1842,13 @@ namespace Akka.Actor.Internal
     public class ActorSystemImpl : Akka.Actor.ExtendedActorSystem
     {
         public ActorSystemImpl(string name) { }
-        public ActorSystemImpl(string name, Akka.Configuration.Config config, Akka.Actor.Setup.ActorSystemSetup setup) { }
+        public ActorSystemImpl(string name, Akka.Configuration.Config config, Akka.Actor.Setup.ActorSystemSetup setup, System.Nullable<Akka.Util.Option<Akka.Actor.Props>> guardianProps = null) { }
         public override Akka.Actor.ActorProducerPipelineResolver ActorPipelineResolver { get; }
         public override Akka.Actor.IActorRef DeadLetters { get; }
         public override Akka.Dispatch.Dispatchers Dispatchers { get; }
         public override Akka.Event.EventStream EventStream { get; }
         public override Akka.Actor.IInternalActorRef Guardian { get; }
+        public Akka.Util.Option<Akka.Actor.Props> GuardianProps { get; }
         public override Akka.Event.ILoggingAdapter Log { get; }
         public override Akka.Actor.IInternalActorRef LookupRoot { get; }
         public override Akka.Dispatch.Mailboxes Mailboxes { get; }
@@ -2452,9 +2454,10 @@ namespace Akka.Dispatch
     }
     public sealed class Dispatchers
     {
+        public static readonly string DefaultBlockingDispatcherId;
         public static readonly string DefaultDispatcherId;
         public static readonly string SynchronizedDispatcherId;
-        public Dispatchers(Akka.Actor.ActorSystem system, Akka.Dispatch.IDispatcherPrerequisites prerequisites) { }
+        public Dispatchers(Akka.Actor.ActorSystem system, Akka.Dispatch.IDispatcherPrerequisites prerequisites, Akka.Event.ILoggingAdapter logger) { }
         public Akka.Configuration.Config DefaultDispatcherConfig { get; }
         public Akka.Dispatch.MessageDispatcher DefaultGlobalDispatcher { get; }
         public Akka.Dispatch.IDispatcherPrerequisites Prerequisites { get; }
@@ -4838,6 +4841,7 @@ namespace Akka.Util
         public static readonly Akka.Util.Option<T> None;
         public Option(T value) { }
         public bool HasValue { get; }
+        public bool IsEmpty { get; }
         public T Value { get; }
         public bool Equals(Akka.Util.Option<T> other) { }
         public override bool Equals(object obj) { }

src/core/Akka.API.Tests/CoreAPISpec.ApproveStreams.approved.txt

@@ -19,6 +19,7 @@ namespace Akka.Streams
     }
     public class static ActorAttributes
     {
+        public static Akka.Streams.ActorAttributes.Dispatcher IODispatcher { get; }
         public static Akka.Streams.Attributes CreateDebugLogging(bool enabled) { }
         public static Akka.Streams.Attributes CreateDispatcher(string dispatcherName) { }
         public static Akka.Streams.Attributes CreateFuzzingMode(bool enabled) { }
@@ -140,12 +141,14 @@ namespace Akka.Streams
         public readonly int SyncProcessingLimit;
         public ActorMaterializerSettings(int initialInputBufferSize, int maxInputBufferSize, string dispatcher, Akka.Streams.Supervision.Decider supervisionDecider, Akka.Streams.StreamSubscriptionTimeoutSettings subscriptionTimeoutSettings, Akka.Streams.Dsl.StreamRefSettings streamRefSettings, bool isDebugLogging, int outputBurstLimit, bool isFuzzingMode, bool isAutoFusing, int maxFixedBufferSize, int syncProcessingLimit = 1000) { }
         public static Akka.Streams.ActorMaterializerSettings Create(Akka.Actor.ActorSystem system) { }
+        public override bool Equals(object obj) { }
         public Akka.Streams.ActorMaterializerSettings WithAutoFusing(bool isAutoFusing) { }
         public Akka.Streams.ActorMaterializerSettings WithDebugLogging(bool isEnabled) { }
         public Akka.Streams.ActorMaterializerSettings WithDispatcher(string dispatcher) { }
         public Akka.Streams.ActorMaterializerSettings WithFuzzingMode(bool isFuzzingMode) { }
         public Akka.Streams.ActorMaterializerSettings WithInputBuffer(int initialSize, int maxSize) { }
         public Akka.Streams.ActorMaterializerSettings WithMaxFixedBufferSize(int maxFixedBufferSize) { }
+        public Akka.Streams.ActorMaterializerSettings WithOutputBurstLimit(int limit) { }
         public Akka.Streams.ActorMaterializerSettings WithStreamRefSettings(Akka.Streams.Dsl.StreamRefSettings settings) { }
         public Akka.Streams.ActorMaterializerSettings WithSubscriptionTimeoutSettings(Akka.Streams.StreamSubscriptionTimeoutSettings settings) { }
         public Akka.Streams.ActorMaterializerSettings WithSupervisionStrategy(Akka.Streams.Supervision.Decider decider) { }

src/core/Akka.Cluster.Tests/ClusterConfigSpec.cs

@@ -45,7 +45,7 @@ public void Clustering_must_be_able_to_parse_generic_cluster_config_elements()
             settings.MinNrOfMembers.Should().Be(1);
             settings.MinNrOfMembersOfRole.Should().Equal(ImmutableDictionary<string, int>.Empty);
             settings.Roles.Should().BeEquivalentTo(ImmutableHashSet<string>.Empty);
-            settings.UseDispatcher.Should().Be(Dispatchers.DefaultDispatcherId);
+            settings.UseDispatcher.Should().Be(Dispatchers.InternalDispatcherId);
             settings.GossipDifferentViewProbability.Should().Be(0.8);
             settings.ReduceGossipDifferentViewProbability.Should().Be(400);
 

src/core/Akka.Cluster/ClusterSettings.cs

@@ -70,7 +70,7 @@ public ClusterSettings(Config config, string systemName)
             MinNrOfMembers = clusterConfig.GetInt("min-nr-of-members", 0);
 
             _useDispatcher = clusterConfig.GetString("use-dispatcher", null);
-            if (String.IsNullOrEmpty(_useDispatcher)) _useDispatcher = Dispatchers.DefaultDispatcherId;
+            if (string.IsNullOrEmpty(_useDispatcher)) _useDispatcher = Dispatchers.InternalDispatcherId;
             GossipDifferentViewProbability = clusterConfig.GetDouble("gossip-different-view-probability", 0);
             ReduceGossipDifferentViewProbability = clusterConfig.GetInt("reduce-gossip-different-view-probability", 0);
             SchedulerTickDuration = clusterConfig.GetTimeSpan("scheduler.tick-duration", null);

src/core/Akka.Cluster/Configuration/Cluster.conf

@@ -128,8 +128,8 @@ akka {
     # Disable with "off".
     publish-stats-interval = off
 
-    # The id of the dispatcher to use for cluster actors. If not specified
-    # default dispatcher is used.
+    # The id of the dispatcher to use for cluster actors. 
+    # If not specified, the internal dispatcher is used.
     # If specified you need to define the settings of the actual dispatcher.
     use-dispatcher = ""
 

src/core/Akka.MultiNodeTestRunner.Shared/Akka.MultiNodeTestRunner.Shared.csproj

@@ -5,6 +5,9 @@
     <TargetFrameworks>$(NetStandardLibVersion)</TargetFrameworks>
     <EnableDefaultCompileItems>false</EnableDefaultCompileItems>
     <GenerateAssemblyInfo>false</GenerateAssemblyInfo>
+    <!-- FIX for "<GenerateTargetFrameworkAttribute>false</GenerateTargetFrameworkAttribute>..." build error with the latest VS2019 update-->
+    <GenerateTargetFrameworkAttribute>false</GenerateTargetFrameworkAttribute>
+    <!-- END FIX-->
   </PropertyGroup>
 
   <ItemGroup>

src/core/Akka.Streams.Tests/Dsl/UnfoldResourceAsyncSourceSpec.cs

@@ -293,7 +293,7 @@ public void A_UnfoldResourceAsyncSource_must_use_dedicated_blocking_io_dispatche
                     var actorRef = refs.First(@ref => @ref.Path.ToString().Contains("unfoldResourceSourceAsync"));
                     try
                     {
-                        Utils.AssertDispatcher(actorRef, "akka.stream.default-blocking-io-dispatcher");
+                        Utils.AssertDispatcher(actorRef, ActorAttributes.IODispatcher.Name);
                     }
                     finally
                     {

src/core/Akka.Streams.Tests/Dsl/UnfoldResourceSourceSpec.cs

@@ -211,7 +211,7 @@ public void A_UnfoldResourceSource_must_use_dedicated_blocking_io_dispatcher_by_
                     var actorRef = refs.First(@ref => @ref.Path.ToString().Contains("unfoldResourceSource"));
                     try
                     {
-                        Utils.AssertDispatcher(actorRef, "akka.stream.default-blocking-io-dispatcher");
+                        Utils.AssertDispatcher(actorRef, ActorAttributes.IODispatcher.Name);
                     }
                     finally
                     {