From 8023a7adee2c7fa2fae583ad7f1044483f967ab1 Mon Sep 17 00:00:00 2001
From: Roger Johansson <rogeralsing@gmail.com>
Date: Fri, 27 Jan 2023 19:46:18 +0100
Subject: [PATCH] Harden gossip consensus (#1911)

* test larger clusters
* remove redundant purge
---
 src/Proto.Cluster/Gossip/Gossip.cs           | 6 ++----
 src/Proto.Cluster/Gossip/GossipActor.cs      | 4 +---
 src/Proto.Cluster/Gossip/Gossiper.cs         | 2 +-
 src/Proto.Cluster/GossipContracts.proto      | 2 +-
 tests/Proto.Cluster.Tests/GossipCoreTests.cs | 4 ++--
 5 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/src/Proto.Cluster/Gossip/Gossip.cs b/src/Proto.Cluster/Gossip/Gossip.cs
index 198b70aba3..924fd4bb55 100644
--- a/src/Proto.Cluster/Gossip/Gossip.cs
+++ b/src/Proto.Cluster/Gossip/Gossip.cs
@@ -90,9 +90,7 @@ public ImmutableList<GossipUpdate> ReceiveState(GossipState remoteState)
         }
 
         _state = newState;
-
-        //TODO: Optimize
-        Purge();
+        
         CheckConsensus(updatedKeys);
 
         return updates.ToImmutableList();
@@ -253,7 +251,7 @@ private void Purge()
     {
         //find all members that have sent topology
         var members = _getMembers();
-
+        
         foreach (var memberId in _state.Members.Keys.ToArray())
         {
             if (!members.Contains(memberId))
diff --git a/src/Proto.Cluster/Gossip/GossipActor.cs b/src/Proto.Cluster/Gossip/GossipActor.cs
index 5921aa2a1c..012692e41a 100644
--- a/src/Proto.Cluster/Gossip/GossipActor.cs
+++ b/src/Proto.Cluster/Gossip/GossipActor.cs
@@ -16,7 +16,6 @@ public class GossipActor : IActor
     private static readonly ILogger Logger = Log.CreateLogger<GossipActor>();
     private readonly TimeSpan _gossipRequestTimeout;
     private readonly IGossip _internal;
-    private readonly ActorSystem _system;
 
     // lookup from state key -> consensus checks
 
@@ -29,11 +28,10 @@ public GossipActor(
         int gossipMaxSend
     )
     {
-        _system = system;
         _gossipRequestTimeout = gossipRequestTimeout;
 
         _internal = new Gossip(myId, gossipFanout, gossipMaxSend, instanceLogger,
-            () => _system.Cluster().MemberList.GetMembers());
+            () => system.Cluster().MemberList.GetMembers());
     }
 
     public Task ReceiveAsync(IContext context) =>
diff --git a/src/Proto.Cluster/Gossip/Gossiper.cs b/src/Proto.Cluster/Gossip/Gossiper.cs
index 5a1e43d75d..61e3cf723f 100644
--- a/src/Proto.Cluster/Gossip/Gossiper.cs
+++ b/src/Proto.Cluster/Gossip/Gossiper.cs
@@ -114,7 +114,7 @@ public async Task<ImmutableDictionary<string, GossipKeyValue>> GetStateEntry(str
         try
         {
             var res = await _context.RequestAsync<GetGossipStateEntryResponse>(_pid,
-                new GetGossipStateEntryRequest(key));
+                new GetGossipStateEntryRequest(key),CancellationTokens.FromSeconds(5));
 
             return res.State;
         }
diff --git a/src/Proto.Cluster/GossipContracts.proto b/src/Proto.Cluster/GossipContracts.proto
index 3e2273ac91..92957005e9 100644
--- a/src/Proto.Cluster/GossipContracts.proto
+++ b/src/Proto.Cluster/GossipContracts.proto
@@ -32,7 +32,7 @@ message GossipState {
 //we still know when _we_ as in this node, got this data.
 //and we can measure time from then til now.
 //
-//if we got a hear-beat from another node, and X seconds pass, we can assume it to be dead
+//if we got a heartbeat from another node, and X seconds pass, we can assume it to be dead
 message GossipKeyValue {
   int64 sequence_number = 2; //version is local to the owner member
   google.protobuf.Any value = 4; //value is any format
diff --git a/tests/Proto.Cluster.Tests/GossipCoreTests.cs b/tests/Proto.Cluster.Tests/GossipCoreTests.cs
index 047123082e..d8de25f45e 100644
--- a/tests/Proto.Cluster.Tests/GossipCoreTests.cs
+++ b/tests/Proto.Cluster.Tests/GossipCoreTests.cs
@@ -30,8 +30,8 @@ public GossipCoreTests(ITestOutputHelper output)
     [Fact]
     public async Task Large_cluster_should_get_topology_consensus()
     {
-        const int memberCount = 50;
-        const int fanout = 4;
+        const int memberCount = 300;
+        const int fanout = 3;
 
         var members =
             Enumerable