semaphore guard for event handler

Azure · Sep 5, 2024 · 193186f · 193186f
1 parent df8a350
commit 193186f
Showing 1 changed file with 18 additions and 1 deletion.
diff --git a/src/Microsoft.Azure.Relay.Bridge/Configuration/Config.cs b/src/Microsoft.Azure.Relay.Bridge/Configuration/Config.cs
@@ -478,7 +478,24 @@ public static Config LoadConfig(CommandLineSettings commandLineSettings)
                 Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.CommonApplicationData), $"{azbridge}\\{azbridge}_config.machine.yml");
 
             Config config = LoadConfigFile(machineConfigFileName);
-            Action onchange = () => { var cfg = LoadConfig(commandLineSettings); config.RaiseChanged(cfg); };
+            SemaphoreSlim semaphore = new SemaphoreSlim(1, 1);
+            Action onchange = () => { 
+                // if we can't get the semaphore, we're already processing a change
+                if ( semaphore.Wait(0))
+                {
+                    // wait a second to make sure the file is done being written/changed
+                    Thread.Sleep(1000);
+                    try
+                    {
+                        Config cfg = LoadConfigFile(machineConfigFileName);
+                        config.RaiseChanged(cfg);
+                    }
+                    finally
+                    {
+                        semaphore.Release();
+                    }
+                }
+            };
 
             if (Directory.Exists(Path.GetDirectoryName(machineConfigFileName)))
             {