await lock.acquire()
Concurrency & Async

Meaning

Asynchronously acquires an asyncio lock, suspending the current coroutine until the lock is available. It addresses the pain point of race conditions on shared mutable state in concurrent async code. It is triggered when entering a critical section that requires mutual exclusion without blocking the event loop.

Primary Function

Synchronization

Communicative Purpose

Request exclusive access to a shared resource in asynchronous code, yielding control until the lock is free.

Pattern

await lock.acquire(timeout=value)

Core Structure

await ....acquire()

Função primária

Synchronization

Propósito comunicativo

Request exclusive access to a shared resource in asynchronous code, yielding control until the lock is free.

Situações de gatilho

Async applications: protecting shared mutable state from concurrent modifications; Resource management: limiting concurrent access to an API or database connection; State synchronization: ensuring only one coroutine executes a critical transaction at a time.

Contextos

Inside async def functions when using asyncio.Lock, asyncio.Condition, asyncio.Semaphore, or any custom lock object with an awaitable acquire() method.

Padrão

await lock.acquire(timeout=value)

Estrutura central

await ....acquire()

Slots de substituição

lock: asyncio.Lock or similar awaitable object, timeout: float or None

Colocados típicos

  • asyncio.Lock
  • asyncio.Semaphore
  • lock.release()
  • try...finally
  • async with

Substituições comuns

  • lock can be asyncio.Lock()
  • asyncio.Condition()
  • asyncio.Semaphore()
  • or a custom lock implementing awaitable acquire().

Erros comuns

Forgetting to await the call (cause: treating coroutine as synchronous; consequence: lock is never actually acquired, leading to race conditions), Failing to release in a finally block (cause: early return or unhandled exception; consequence: permanent deadlock), Using threading.Lock (cause: confusing sync and async primitives; consequence: blocks the entire event loop)

Similar / contraste

lock.acquire() without await returns a coroutine; lock.release() releases the lock; async with lock: provides a context‑manager equivalent.

Interferências

Coming from threading: using threading.Lock.acquire() which blocks the OS thread → use asyncio.Lock.acquire() which yields control to the event loop

Família do chunk

  • asyncio synchronization primitives

Nuance

Do not use when async with lock: is available, as it handles release automatically. Acquiring a lock has minimal overhead, but failing to release it will halt all other coroutines waiting for that lock. The timeout parameter returns False if the lock cannot be acquired in time, rather than raising an exception.

Efeito pragmático

Signals intent to gain exclusive access while cooperatively yielding control, enabling cooperative multitasking.

Dica de memória

Think ‘await the lock’ to pause until you can proceed.

Nota

Always pair with a matching lock.release() or prefer async with lock: for automatic acquire/release.

Upgrade path

Consider using 'async with lock:' for automatic acquire and release.

Frequência: HighFormulaicidade: Semi-fixedTipo de construção: method call prefixed with awaitPrioridade de aquisição: Active recallPrioridade de output: OutputTag de espaçamento: Short-term

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