Fix multiple backups running at once

- Backups now have a cooldown, default of 30 seconds
- Backups now have a lock, in the event of a TOC/TOU race condition, the lock will stop duplicate backups

Libraries/SPTarkov.Server.Assets/SPT_Data/configs/backup.json

@@ -1,6 +1,7 @@
 {
   "enabled": true,
   "maxBackups": 15,
+  "backupCooldown": 30,
   "directory": "./user/profiles/backups",
   "backupInterval": {
     "enabled": false,

Libraries/SPTarkov.Server.Core/Models/Spt/Config/BackupConfig.cs

@@ -13,6 +13,9 @@ public record BackupConfig : BaseConfig
     [JsonPropertyName("maxBackups")]
     public int MaxBackups { get; set; }
 
+    [JsonPropertyName("backupCooldown")]
+    public int BackupCooldown { get; set; }
+
     [JsonPropertyName("directory")]
     public string Directory { get; set; } = string.Empty;
 

Libraries/SPTarkov.Server.Core/Services/BackupService.cs

@@ -21,6 +21,9 @@ public class BackupService
     // Runs Init() every x minutes
     protected Timer _backupIntervalTimer;
 
+    protected SemaphoreSlim BackupLock = new SemaphoreSlim(1, 1);
+    protected long LastBackupTimestamp;
+
     protected readonly FileUtil FileUtil;
     protected readonly JsonUtil JsonUtil;
     protected readonly ISptLogger<BackupService> Logger;
@@ -78,7 +81,7 @@ public class BackupService
     }
 
     /// <summary>
-    ///     Initializes the backup process. <br />
+    ///     Run the backup process. <br />
     ///     This method orchestrates the profile backup service. Handles copying profiles to a backup directory and cleaning
     ///     up old backups if the number exceeds the configured maximum.
     /// </summary>
@@ -89,6 +92,24 @@ public class BackupService
             return;
         }
 
+        // Make sure we don't back up too often by using a configurable Cooldown
+        var currentTimestamp = DateTimeOffset.UtcNow.ToUnixTimeSeconds();
+        if (currentTimestamp < LastBackupTimestamp + BackupConfig.BackupCooldown)
+        {
+            return;
+        }
+        LastBackupTimestamp = currentTimestamp;
+
+        // If the backup lock is already locked, skip backup. This is to stop TOC/TOU race conditions above
+        // Passing 0 is a non-blocking Wait, will return false if the lock can't be acquired
+        bool lockAcquired = await BackupLock.WaitAsync(0);
+        if (!lockAcquired)
+        {
+            return;
+        }
+
+        try
+        {
             var targetDir = GenerateBackupTargetDir();
 
             // Fetch all profiles in the profile directory.
@@ -147,6 +168,11 @@ public class BackupService
 
             CleanBackups();
         }
+        finally
+        {
+            BackupLock.Release();
+        }
+    }
 
     /// <summary>
     ///     Check to see if the backup service is enabled via the config.