fix: fix daemon.lock race on mutagen startup

spikecurtis · spikecurtis · commit c2bc5a9a788c · 2025-05-13T16:57:21.000+04:00
diff --git a/App/Services/MutagenController.cs b/App/Services/MutagenController.cs
@@ -441,6 +441,7 @@ private async Task<SyncSessionControllerStateModel> UpdateState(MutagenClient cl
     /// </summary>
     private async Task<MutagenClient> EnsureDaemon(CancellationToken ct)
     {
+        _logger.LogDebug("EnsureDaemon called");
         ObjectDisposedException.ThrowIf(_disposing, typeof(MutagenController));
         if (_mutagenClient != null && _daemonProcess != null)
             return _mutagenClient;
@@ -479,12 +480,14 @@ private async Task<MutagenClient> EnsureDaemon(CancellationToken ct)
     /// </summary>
     private async Task<MutagenClient> StartDaemon(CancellationToken ct)
     {
+        _logger.LogDebug("StartDaemon called");
         // Stop the running daemon
         if (_daemonProcess != null) await StopDaemon(ct);
 
         // Attempt to stop any orphaned daemon
         try
         {
+            _logger.LogDebug("creating MutagenClient to stop orphan");
             var client = new MutagenClient(_mutagenDataDirectory);
             await client.Daemon.TerminateAsync(new DaemonTerminateRequest(), cancellationToken: ct);
         }
@@ -496,6 +499,10 @@ private async Task<MutagenClient> StartDaemon(CancellationToken ct)
         {
             // Mainline; no daemon running.
         }
+        finally
+        {
+            _logger.LogDebug("finished with orphan mutagen client");
+        }
 
         // If we get some failure while creating the log file or starting the process, we'll retry
         // it up to 5 times x 100ms. Those issues should resolve themselves quickly if they are
@@ -528,6 +535,7 @@ private async Task<MutagenClient> StartDaemon(CancellationToken ct)
             ct.ThrowIfCancellationRequested();
             try
             {
+                _logger.LogDebug("creating mainline mutagen client");
                 var client = new MutagenClient(_mutagenDataDirectory);
                 _ = await client.Daemon.VersionAsync(new VersionRequest(), cancellationToken: ct);
                 _mutagenClient = client;
diff --git a/MutagenSdk/MutagenClient.cs b/MutagenSdk/MutagenClient.cs
@@ -16,26 +16,6 @@ public class MutagenClient : IDisposable
 
     public MutagenClient(string dataDir)
     {
-        // Check for the lock file first, since it should exist if it's running.
-        var daemonLockFile = Path.Combine(dataDir, "daemon", "daemon.lock");
-        if (!File.Exists(daemonLockFile))
-            throw new FileNotFoundException(
-                "Mutagen daemon lock file not found, did the mutagen daemon start successfully?", daemonLockFile);
-
-        // We should not be able to open the lock file.
-        try
-        {
-            using var _ = File.Open(daemonLockFile, FileMode.Open, FileAccess.Write, FileShare.None);
-            // We throw a FileNotFoundException if we could open the file because
-            // it means the same thing and allows us to return the path nicely.
-            throw new InvalidOperationException(
-                $"Mutagen daemon lock file '{daemonLockFile}' is unlocked, did the mutagen daemon start successfully?");
-        }
-        catch (IOException)
-        {
-            // this is what we expect
-        }
-
         // Read the IPC named pipe address from the sock file.
         var daemonSockFile = Path.Combine(dataDir, "daemon", "daemon.sock");
         if (!File.Exists(daemonSockFile))

Original file line number	Diff line number	Diff line change
`@@ -441,6 +441,7 @@ private async Task<SyncSessionControllerStateModel> UpdateState(MutagenClient cl`
`441`	`441`	`/// </summary>`
`442`	`442`	`private async Task<MutagenClient> EnsureDaemon(CancellationToken ct)`
`443`	`443`	`{`
	`444`	`+ _logger.LogDebug("EnsureDaemon called");`
`444`	`445`	`ObjectDisposedException.ThrowIf(_disposing, typeof(MutagenController));`
`445`	`446`	`if (_mutagenClient != null && _daemonProcess != null)`
`446`	`447`	`return _mutagenClient;`
`@@ -479,12 +480,14 @@ private async Task<MutagenClient> EnsureDaemon(CancellationToken ct)`
`479`	`480`	`/// </summary>`
`480`	`481`	`private async Task<MutagenClient> StartDaemon(CancellationToken ct)`
`481`	`482`	`{`
	`483`	`+ _logger.LogDebug("StartDaemon called");`
`482`	`484`	`// Stop the running daemon`
`483`	`485`	`if (_daemonProcess != null) await StopDaemon(ct);`
`484`	`486`
`485`	`487`	`// Attempt to stop any orphaned daemon`
`486`	`488`	`try`
`487`	`489`	`{`
	`490`	`+ _logger.LogDebug("creating MutagenClient to stop orphan");`
`488`	`491`	`var client = new MutagenClient(_mutagenDataDirectory);`
`489`	`492`	`await client.Daemon.TerminateAsync(new DaemonTerminateRequest(), cancellationToken: ct);`
`490`	`493`	`}`
`@@ -496,6 +499,10 @@ private async Task<MutagenClient> StartDaemon(CancellationToken ct)`
`496`	`499`	`{`
`497`	`500`	`// Mainline; no daemon running.`
`498`	`501`	`}`
	`502`	`+ finally`
	`503`	`+ {`
	`504`	`+ _logger.LogDebug("finished with orphan mutagen client");`
	`505`	`+ }`
`499`	`506`
`500`	`507`	`// If we get some failure while creating the log file or starting the process, we'll retry`
`501`	`508`	`// it up to 5 times x 100ms. Those issues should resolve themselves quickly if they are`
`@@ -528,6 +535,7 @@ private async Task<MutagenClient> StartDaemon(CancellationToken ct)`
`528`	`535`	`ct.ThrowIfCancellationRequested();`
`529`	`536`	`try`
`530`	`537`	`{`
	`538`	`+ _logger.LogDebug("creating mainline mutagen client");`
`531`	`539`	`var client = new MutagenClient(_mutagenDataDirectory);`
`532`	`540`	`_ = await client.Daemon.VersionAsync(new VersionRequest(), cancellationToken: ct);`
`533`	`541`	`_mutagenClient = client;`