await barrier.wait()

Concurrency & Async

Meaning

Waits until all participating coroutines have reached the barrier point, then releases them to continue.

Primary Function

Synchronizes concurrent coroutines at a synchronization point.

Communicative Purpose

Signals that a coroutine has reached a synchronization barrier and is awaiting other participants.

Pattern

await barrier.wait()

Core Structure

await ....wait()

Função primária

Synchronizes concurrent coroutines at a synchronization point.

Propósito comunicativo

Signals that a coroutine has reached a synchronization barrier and is awaiting other participants.

Situações de gatilho

When a coroutine needs to wait for other concurrent tasks to reach a common checkpoint before proceeding to the next phase.

Contextos

Asyncio concurrent programming, parallel phases, barrier-based synchronization in async contexts.

Padrão

await barrier.wait()

Estrutura central

await ....wait()

Slots de substituição

barrier: asyncio.Barrier or compatible async barrier object

Colocados típicos

asyncio.Barrier
asyncio.Lock
asyncio.Event
asyncio.gather
asyncio.wait

Substituições comuns

asyncio.Event.wait() — one-shot signal without group coordination
no party count
asyncio.Condition.wait() — predicate-based release with notify
more flexible but heavier
threading.Barrier.wait() — synchronous blocking equivalent for threads
not awaitable

Erros comuns

Forgetting to await the call, yielding a dangling coroutine object; calling wait() on a barrier without ensuring all parties will invoke it, leading to deadlock; reusing a barrier after it has been broken without resetting it.

Similar / contraste

Similar to asyncio.Event.wait() and asyncio.Condition.wait(); differs from asyncio.Event.set() which signals without waiting. Contrasts with asyncio.Lock.acquire() which grants exclusive access rather than group synchronization.

Interferências

Coming from threading.Barrier: calling barrier.wait() without await returns a coroutine object instead of blocking — must use await in asyncio. Coming from Go: sync.WaitGroup uses separate Add/Done/Wait calls rather than a single wait() per party — asyncio.Barrier requires every party to call wait() explicitly. Coming from C++: std::latch is one-use and counts down — asyncio.Barrier resets automatically for the next phase.

Família do chunk

asyncio synchronization primitives

Nuance

barrier.wait() blocks until the number of calls equals the barrier's party count; unlike an Event, it does not retain state after release and must be recreated or reset for reuse.

Efeito pragmático

Communicates readiness to proceed and coordinates phase transitions among concurrent tasks.

Dica de memória

Think of a gate that only opens when all runners have arrived.

Nota

The wait() method returns a bool indicating whether the caller is the leader (the last arriver); this can be used to perform leader‑only actions after the barrier.

Upgrade path

Learn asyncio.Event → asyncio.Barrier → asyncio.Condition for more complex coordination patterns.

Frequência: MediumFormulaicidade: Semi-fixedTipo de construção: await_expressionPrioridade de aquisição: Active recallPrioridade de output: OutputTag de espaçamento: Medium-term

Examples

import asyncio async def worker(worker_id, barrier): for phase in range(3): result = await process_chunk(worker_id, phase) print(f"Worker {worker_id} finished phase {phase}") await barrier.wait() print(f"Worker {worker_id} starting phase {phase + 1}") async def process_chunk(worker_id, phase): await asyncio.sleep(0.1) return worker_id * phase async def main(): barrier = asyncio.Barrier(3) tasks = [asyncio.create_task(worker(i, barrier)) for i in range(3)] await asyncio.gather(*tasks) asyncio.run(main())

import asyncio async def producer(queue, barrier): for i in range(5): await queue.put(f"item-{i}") await barrier.wait() await queue.put(None) async def consumer(queue, barrier): await barrier.wait() while True: item = await queue.get() if item is None: break print(f"Consumed {item}") async def main(): queue = asyncio.Queue() barrier = asyncio.Barrier(2) await asyncio.gather(producer(queue, barrier), consumer(queue, barrier)) asyncio.run(main())

import asyncio async def participant(pid, barrier): print(f"Participant {pid} doing initial work") await asyncio.sleep(0.1 * pid) is_leader = await barrier.wait() if is_leader: print(f"Participant {pid} elected leader, performing shared cleanup") else: print(f"Participant {pid} following leader") async def main(): barrier = asyncio.Barrier(4) tasks = [asyncio.create_task(participant(i, barrier)) for i in range(4)] await asyncio.gather(*tasks) asyncio.run(main())