Feature/feed DNS to discv4 (#6035)

* Feed ENR dns to discovery appp

* Missed a file

* Unit tests

* Fixed misconfiguration

src/Nethermind/Nethermind.Init/Steps/InitializeNetwork.cs

@@ -559,6 +559,13 @@ private async Task InitPeer()
         NodeRecordSigner nodeRecordSigner = new(_api.EthereumEcdsa, new PrivateKeyGenerator().Generate());
         EnrRecordParser enrRecordParser = new(nodeRecordSigner);
         EnrDiscovery enrDiscovery = new(enrRecordParser, _api.LogManager); // initialize with a proper network
+
+        if (!_networkConfig.DisableDiscV4DnsFeeder)
+        {
+            // Feed some nodes into discoveryApp in case all bootnodes is faulty.
+            _api.DisposeStack.Push(new NodeSourceToDiscV4Feeder(enrDiscovery, _api.DiscoveryApp, 50));
+        }
+
         CompositeNodeSource nodeSources = new(_api.StaticNodesManager, nodesLoader, enrDiscovery, _api.DiscoveryApp);
         _api.PeerPool = new PeerPool(nodeSources, _api.NodeStatsManager, peerStorage, _networkConfig, _api.LogManager);
         _api.PeerManager = new PeerManager(

src/Nethermind/Nethermind.Network.Discovery.Test/NodeSourceToDiscV4Feeder.cs

@@ -0,0 +1,38 @@
+// SPDX-FileCopyrightText: 2023 Demerzel Solutions Limited
+// SPDX-License-Identifier: LGPL-3.0-only
+
+using Nethermind.Core.Test.Builders;
+using Nethermind.Stats.Model;
+using NSubstitute;
+using NUnit.Framework;
+
+namespace Nethermind.Network.Discovery.Test;
+
+public class NodeSourceToDiscV4FeederTests
+{
+    [Test]
+    public void Test_ShouldAddNodeToDiscover()
+    {
+        INodeSource source = Substitute.For<INodeSource>();
+        IDiscoveryApp discoveryApp = Substitute.For<IDiscoveryApp>();
+        using NodeSourceToDiscV4Feeder feeder = new(source, discoveryApp, 10);
+        source.NodeAdded += Raise.EventWith(new NodeEventArgs(new Node(TestItem.PublicKeyA, TestItem.IPEndPointA)));
+
+        discoveryApp.Received().AddNodeToDiscovery(Arg.Any<Node>());
+    }
+
+    [Test]
+    public void Test_ShouldLimitAddedNode()
+    {
+        INodeSource source = Substitute.For<INodeSource>();
+        IDiscoveryApp discoveryApp = Substitute.For<IDiscoveryApp>();
+        using NodeSourceToDiscV4Feeder feeder = new(source, discoveryApp, 10);
+
+        for (int i = 0; i < 20; i++)
+        {
+            source.NodeAdded += Raise.EventWith(new NodeEventArgs(new Node(TestItem.PublicKeyA, TestItem.IPEndPointA)));
+        }
+
+        discoveryApp.Received(10).AddNodeToDiscovery(Arg.Any<Node>());
+    }
+}

src/Nethermind/Nethermind.Network.Discovery/NodeSourceToDiscV4Feeder.cs

@@ -0,0 +1,32 @@
+// SPDX-FileCopyrightText: 2023 Demerzel Solutions Limited
+// SPDX-License-Identifier: LGPL-3.0-only
+
+namespace Nethermind.Network.Discovery;
+
+public class NodeSourceToDiscV4Feeder : IDisposable
+{
+    private readonly INodeSource _nodeSource;
+    private readonly IDiscoveryApp _discoveryApp;
+    private readonly int _maxNodes;
+    private int _addedNodes = 0;
+
+    public NodeSourceToDiscV4Feeder(INodeSource nodeSource, IDiscoveryApp discoveryApp, int maxNodes)
+    {
+        nodeSource.NodeAdded += AddToDiscoveryApp;
+        _nodeSource = nodeSource;
+        _discoveryApp = discoveryApp;
+        _maxNodes = maxNodes;
+    }
+
+    private void AddToDiscoveryApp(object? sender, NodeEventArgs e)
+    {
+        if (_addedNodes >= _maxNodes) return;
+        _addedNodes++;
+        _discoveryApp.AddNodeToDiscovery(e.Node);
+    }
+
+    public void Dispose()
+    {
+        _nodeSource.NodeAdded -= AddToDiscoveryApp;
+    }
+}

src/Nethermind/Nethermind.Network/Config/INetworkConfig.cs

@@ -97,5 +97,8 @@ public interface INetworkConfig : IConfig
 
         [ConfigItem(DefaultValue = null, HiddenFromDocs = true, Description = "[TECHNICAL] Only allow peer with clientId matching this regex. Useful for testing. eg: 'besu' to only connect to BeSU")]
         string? ClientIdMatcher { get; set; }
+
+        [ConfigItem(DefaultValue = "false", HiddenFromDocs = true, Description = "[TECHNICAL] Disable feeding ENR DNS records to discv4 table")]
+        bool DisableDiscV4DnsFeeder { get; set; }
     }
 }

src/Nethermind/Nethermind.Network/Config/NetworkConfig.cs

@@ -39,5 +39,6 @@ public class NetworkConfig : INetworkConfig
         public int ConnectTimeoutMs { get; set; } = 2000;
         public int ProcessingThreadCount { get; set; } = 1;
         public string? ClientIdMatcher { get; set; } = null;
+        public bool DisableDiscV4DnsFeeder { get; set; } = false;
     }
 }