Handling Concurrent NSOperationQueue Execution in macOS 13.6 Leading to Resource Contention
I'm not sure how to approach I'm collaborating on a project where I've looked through the documentation and I'm still confused about I'm sure I'm missing something obvious here, but I'm experiencing issues with concurrent tasks in an NSOperationQueue on macOS 13.6... Specifically, when I try to execute multiple operations that access a shared resource, I'm working with intermittent failures. Sometimes, the operations complete without behavior, but often I see the following behavior message in the console: `NSLock failed to lock within the timeout`. I believe this is due to resource contention when two operations try to read/write to the same file simultaneously. Here’s a simplified version of my setup: ```swift let operationQueue = OperationQueue() let fileAccessOperation1 = BlockOperation { // Simulate file access let filePath = "/path/to/shared/resource.txt" let fileData = try? String(contentsOfFile: filePath) print("Data from file: \(fileData ?? \"No Data\")") } let fileAccessOperation2 = BlockOperation { // Simulate file access let filePath = "/path/to/shared/resource.txt" let newData = "New Data" try? newData.write(toFile: filePath, atomically: true, encoding: .utf8) } operationQueue.addOperations([fileAccessOperation1, fileAccessOperation2], waitUntilFinished: false) operationQueue.maxConcurrentOperationCount = 2 ``` I've tried adding locks around the file access code to prevent concurrent writes, but that hasn't resolved the scenario entirely. Here’s an example of how I implemented the locking: ```swift let fileLock = NSLock() let fileAccessOperation1 = BlockOperation { fileLock.lock() defer { fileLock.unlock() } // Access and read file } let fileAccessOperation2 = BlockOperation { fileLock.lock() defer { fileLock.unlock() } // Access and write file } ``` Despite using `NSLock`, I still face contention issues, especially under load. It feels like the operations are not properly synchronized, as I occasionally see data inconsistencies. What would be the best approach to handle concurrent access to shared resources in this scenario without running into these locking issues? Is there a better design pattern or approach that I might be overlooking? I'm working on a CLI tool that needs to handle this. I'd really appreciate any guidance on this. I'm working on a web app that needs to handle this. Thanks in advance! Thanks, I really appreciate it! I'm using Swift 3.11 in this project. Has anyone else encountered this? I'm developing on Ubuntu 22.04 with Swift. Thanks for taking the time to read this! I recently upgraded to Swift 3.10. Hoping someone can shed some light on this.