Coverage for openhcs/io/async_init.py: 40.0%

1""" 

2Async initialization for I/O backends. 

3 

4This module provides background loading of GPU-heavy dependencies 

5to avoid blocking during import while ensuring they're ready when needed. 

6""" 

7import logging 

8import threading 

9 

10logger = logging.getLogger(__name__) 

11 

12_init_complete = threading.Event() 

13_init_thread = None 

14 

15 

16def _background_init(): 

17 """ 

18 Background thread target for async initialization. 

19 

20 NOTE: Due to Python's GIL, importing heavy modules in a background thread 

21 still blocks the main thread during imports. Therefore, we use lazy initialization 

22 for GPU libraries and storage backends - they'll be loaded on first use. 

23 

24 Currently this is a no-op placeholder. GPU registry initialization happens 

25 lazily on first use, not during startup. 

26 """ 

27 try: 

28 logger.info("Background I/O initialization complete (lazy mode - no-op)") 

29 except Exception as e: 

30 logger.error(f"Background I/O initialization failed: {e}") 

31 finally: 

32 _init_complete.set() 

33 

34 

35def start_async_initialization(): 

36 """ 

37 Start background initialization of GPU-heavy dependencies. 

38  

39 Call this during application startup (GUI/CLI) to pre-load 

40 GPU libraries without blocking. Safe to call multiple times. 

41 """ 

42 global _init_thread 

43 

44 if _init_thread is None: 

45 _init_thread = threading.Thread( 

46 target=_background_init, 

47 daemon=True, 

48 name="io-async-init" 

49 ) 

50 _init_thread.start() 

51 logger.info("Started background I/O initialization") 

52 

53 

54def wait_for_initialization(timeout: float = 60.0) -> bool: 

55 """ 

56 Wait for background initialization to complete. 

57  

58 Args: 

59 timeout: Maximum seconds to wait 

60  

61 Returns: 

62 True if completed, False if timeout 

63 """ 

64 return _init_complete.wait(timeout) 

65