add a retry when trying to create the lock file (#9)

* add a retry when trying to create the lock file if UE is trying to read it at the same time

2 files changed, 9 insertions, 2 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 79cf0c050..a163129b0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -21,6 +21,7 @@
 - Improvement: Added support for request tracing when using asio path (use `--log-trace=http_requests` to enable)
 - Improvement: Large attachments and loose files are now split into smaller chunks and stored in blocks during oplog export
 - Improvement: Make sure zenserver reacts and exist on SIGTERM signal
+- Improvement: Retry to create the .lock file at startup to avoid failing launch due to race condition with UE
 - Removed: `--cache-reference-cache-enabled` option has been removed along with the implementation for reference caching in disk cache
 
 ## 5.4.1
diff --git a/src/zenserver/main.cpp b/src/zenserver/main.cpp
index 01e142801..b4cb2464b 100644
--- a/src/zenserver/main.cpp
+++ b/src/zenserver/main.cpp
@@ -145,9 +145,15 @@ ZenEntryPoint::Run()
 
 		if (Ec)
 		{
-			ZEN_WARN("ERROR: Unable to grab lock at '{}' (error: '{}')", LockFilePath, Ec.message());
+			ZEN_WARN("Unable to grab lock at '{}' (error: '{}'), retrying", LockFilePath, Ec.message());
+			Sleep(500);
 
-			std::exit(99);
+			m_LockFile.Create(LockFilePath, MakeLockData(), Ec);
+			if (Ec)
+			{
+				ZEN_WARN("ERROR: Unable to grab lock at '{}' (error: '{}')", LockFilePath, Ec.message());
+				std::exit(99);
+			}
 		}
 
 		InitializeServerLogging(m_ServerOptions);