Choose appropriate synchronization

Select the correct synchronization mechanism based on your execution context and avoid unnecessary synchronization overhead. In async contexts with coroutines, locks are often unnecessary since coroutines run cooperatively in a single thread. Use asyncio.Lock() for async contexts and threading.Lock() for multi-threaded scenarios. When bridging sync and async code with threads, ensure proper context variable propagation and use daemon threads for background tasks.

Key guidelines:

• Async contexts: Coroutines run cooperatively, so locks are usually unnecessary unless coordinating with external threads
• Mixed contexts: Use asyncio.Lock() when coordinating async tasks, threading.Lock() for thread coordination
• Thread creation: Use daemon threads for background tasks and ensure proper exception propagation
• Context variables: Copy context when creating threads to maintain variable scope

Example of proper lock selection:

# Async context - lock usually unnecessary
async def process_nodes_async(self, nodes):
    # Coroutines run cooperatively, no race conditions
    for node in nodes:
        self.state.completed_nodes.add(node)

# Mixed async/thread context - use asyncio.Lock
class GraphExecutor:
    def __init__(self):
        self._lock = asyncio.Lock()  # For async task coordination
    
    async def execute_parallel(self, nodes):
        async with self._lock:  # Only if truly needed
            # Critical section
            pass

# Thread context - use threading.Lock  
class FileManager:
    def __init__(self):
        self._lock = threading.RLock()  # For thread coordination
    
    def write_file(self, data):
        with self._lock:
            # Thread-safe file operations
            pass

Before adding synchronization, verify you actually have a race condition. Many async operations don’t require explicit locking due to the cooperative nature of coroutines.