From a4ade2b78a9b5cb76ae88919f57dc2a05b99a409 Mon Sep 17 00:00:00 2001
From: Jordan Brown <Cyberboss@users.noreply.github.com>
Date: Thu, 31 Dec 2020 23:22:49 -0500
Subject: [PATCH] Fix race condition between swarm server startup and health
 checking

---
 src/Tgstation.Server.Host/Swarm/SwarmService.cs | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/Tgstation.Server.Host/Swarm/SwarmService.cs b/src/Tgstation.Server.Host/Swarm/SwarmService.cs
index 4ed9ae94fd..3cf7efc2b4 100644
--- a/src/Tgstation.Server.Host/Swarm/SwarmService.cs
+++ b/src/Tgstation.Server.Host/Swarm/SwarmService.cs
@@ -41,6 +41,11 @@ namespace Tgstation.Server.Host.Swarm
 		/// </summary>
 		const int UpdateCommitTimeoutMinutes = 10;
 
+		/// <summary>
+		/// Number of seconds between <see cref="forceHealthCheckTcs"/> triggering and a health check being performed.
+		/// </summary>
+		const int SecondsToDelayForcedHealthChecks = 15;
+
 		/// <summary>
 		/// See <see cref="JsonSerializerSettings"/> for the swarm system.
 		/// </summary>
@@ -1060,7 +1065,13 @@ namespace Tgstation.Server.Host.Swarm
 
 					await awakeningTask.ConfigureAwait(false);
 
-					if (!swarmController && !nextForceHealthCheckTask.IsCompleted)
+					if (nextForceHealthCheckTask.IsCompleted && swarmController)
+					{
+						// Intentionally wait a few seconds for the other server to start up before interogating it
+						logger.LogTrace("Next health check triggering in {0}s...", SecondsToDelayForcedHealthChecks);
+						await asyncDelayer.Delay(TimeSpan.FromSeconds(SecondsToDelayForcedHealthChecks), cancellationToken);
+					}
+					else if (!swarmController && !nextForceHealthCheckTask.IsCompleted)
 					{
 						if (!lastControllerHealthCheck.HasValue)
 						{