257 – asyncio locks

The module asyncio provides a class Lock that you can use to guarantee exclusive access to a shared resource:

from asyncio import Lock

lock = asyncio.Lock()

Use it with an async with statement:

async def coroutine1():
  async with lock:
      ...  # Access the shared state.

async def coroutine2():
  async with lock:
      ...  # Access the shared state.

Since both coroutines use lock, they can’t enter the async with at the same time.

Like with any other synchronisation primitive, you have to be careful about deadlocks.