Pyserial和asyncio

Question

在windows机器上尝试使用带有asyncio的pyserial。

受https://stackoverflow.com/a/27927704/1629704的启发，我的代码不断地监视串行端口以获取传入的数据。

# This coroutine is added as a task to the event loop.
@asyncio.coroutine
def get_from_serial_port(self):
    while 1:
        serial_data = yield from self.get_byte_async()
        <doing other stuff with serial_data>

# The method which gets executed in the executor
def get_byte(self):
    data = self.s.read(1)
    time.sleep(0.5)
    tst = self.s.read(self.s.inWaiting())
    data += tst
    return data

# Runs blocking function in executor, yielding the result
@asyncio.coroutine
def get_byte_async(self):
    with concurrent.futures.ThreadPoolExecutor(max_workers=1) as executor:
        res = yield from self.loop.run_in_executor(executor, self.get_byte)
        return res

在返回串行数据之后。在创建新的执行器的while循环中调用协程get_byte_async。我总是学到创建一个新线程是很昂贵的，所以我觉得我应该采取另一种方法，但我不确定如何做到这一点。我一直在读这篇文章https://hackernoon.com/threaded-asynchronous-magic-and-how-to-wield-it-bba9ed602c32#.964j4a5s7

我想我需要在另一个线程中读取串行端口。但是如何将串行数据返回到“主”循环呢？

Answer 1

您可以使用默认的执行器，并使用asyncio lock锁定对get_byte的访问

async def get_byte_async(self):
    async with self.lock:
        return await self.loop.run_in_executor(None, self.get_byte)

或者只需创建一次自己的executor：

async def get_byte_async(self):
    if self.executor is None:
        self.executor = concurrent.futures.ThreadPoolExecutor(max_workers=1)
    return await self.loop.run_in_executor(self.executor, self.get_byte)