Wait for locked file

Azure · Sep 4, 2024 · 993fa63 · 993fa63
1 parent 8130439
commit 993fa63
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Showing 2 changed files with 28 additions and 3 deletions.
diff --git a/src/Microsoft.Azure.Relay.Bridge/Configuration/Config.cs b/src/Microsoft.Azure.Relay.Bridge/Configuration/Config.cs
@@ -17,6 +17,7 @@ namespace Microsoft.Azure.Relay.Bridge.Configuration
     using System.Runtime.Serialization;
     using System.Text;
     using System.Text.RegularExpressions;
+    using System.Threading;
     using YamlDotNet.Core;
 
     /// <summary>
@@ -1173,6 +1174,30 @@ public static Config LoadConfigFile(string fileName)
 
             if (File.Exists(fileName))
             {
+                // test whether the file is locked for reading; if so we'll spin wait
+                // for a bit and then throw an exception
+                for (int i = 0; i < 10; i++)
+                {
+                    try
+                    {
+                        using (var fs = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.None))
+                        {
+                            if (!fs.CanRead)
+                            {
+                                throw BridgeEventSource.Log.ArgumentOutOfRange(
+                                    nameof(fileName),
+                                    $"Configuration file {fileName} is locked for reading",
+                                    null);
+                            }
+                        }
+                        break;
+                    }
+                    catch (IOException)
+                    {
+                        Thread.Sleep(200);
+                    }
+                }
+
                 using (var reader = new StreamReader(fileName))
                 {
                     try

diff --git a/test/unit/Microsoft.Azure.Relay.Bridge.Tests/ConfigTest.cs b/test/unit/Microsoft.Azure.Relay.Bridge.Tests/ConfigTest.cs
@@ -903,9 +903,9 @@ public void ConfigLocalForwardTest()
 
                 // Modify the config file
                 string modifiedConfigContent = "LocalForward:\n" +
-                                              "  - BindAddress : 127.0.97.1\n" +
-                                              "    BindPort : 8009\n" +
-                                              "    RelayName : a1\n";
+                                               "  - BindAddress : 127.0.97.1\n" +
+                                               "    BindPort : 8009\n" +
+                                               "    RelayName : a1\n";
                 File.WriteAllText(initialConfigPath, modifiedConfigContent);
                 // this should have triggered the FS watcher and the config should have been reloaded
                 Thread.Sleep(5000);