类型错误:需要未来或协同程序

2024-03-29 08:41:05 发布

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我尝试在异步ssh上自动重新连接ssh客户端。(SshConnectManager必须留在后台,并在需要时创建ssh会话)

class SshConnectManager(object):
def __init__(self, host, username, password, port=22):
    self._host = host
    self._username = username
    self._password = password
    self._port = port

    self.conn = None
    asyncio.async(self.start_connection)

@asyncio.coroutine
def start_connection(self):
    try:
        Client = self._create_ssh_client()
        self.conn, _ = yield from asyncssh.create_connection(Client,
                                                        self._host, port=self._port,
                                                        username=self._username,
                                                        password=self._password)
    except Exception as e:
        print("Connection error! {}".format(e))
        asyncio.async(self.start_connection())

def _create_ssh_client(self):
    class MySSHClient(asyncssh.SSHClient):
        parent = self
        def connection_lost(self, exc):
            self.parent._handle_connection_lost(exc)
    return MySSHClient

def _handle_connection_lost(self, exc):
    print('Connection lost on {}'.format(self.host))
    print(exc)
    asyncio.async(self.start_connection)


ssh1 = SshConnectManager(settings.host, settings.username, settings.password, settings.port)

asyncio.get_event_loop().run_until_complete(...)

请不要看“创建”ssh_客户端或其他“hak”

问题是:

$ python3 main.py 
Traceback (most recent call last):
  File "main.py", line 75, in <module>
    ssh1 = SshConnectManager(settings.host, settings.username, settings.password, settings.port)
  File "main.py", line 22, in __init__
    asyncio.async(self.start_connection)
  File "/usr/lib/python3.4/asyncio/tasks.py", line 565, in async
    raise TypeError('A Future or coroutine is required')
TypeError: A Future or coroutine is required

但是自我启动连接是很正常的!还是不呢? 或者从同步代码启动异步任务的另一种方法是什么?


Tags: selfasynciohostasyncsettingsportdefusername
1条回答
网友
1楼 · 发布于 2024-03-29 08:41:05

感谢@dano和@boardrider在评论中提供的帮助。 Bug是what@asyncio.coroutine返回需要调用的函数才能获取生成器对象。我忘了做这个。

固定版本:

class SshConnectManager(object):
def __init__(self, host, username, password, port=22):
    self._host = host
    self._username = username
    self._password = password
    self._port = port

    self.conn = None
    # FIX HERE
    asyncio.async(self.start_connection())

@asyncio.coroutine
def start_connection(self):
    try:
        Client = self._create_ssh_client()
        self.conn, _ = yield from asyncssh.create_connection(Client,
                                                        self._host, port=self._port,
                                                        username=self._username,
                                                        password=self._password)
    except Exception as e:
        print("Connection error! {}".format(e))
        asyncio.async(self.start_connection())

def _create_ssh_client(self):
    class MySSHClient(asyncssh.SSHClient):
        parent = self
        def connection_lost(self, exc):
            self.parent._handle_connection_lost(exc)
    return MySSHClient

def _handle_connection_lost(self, exc):
    print('Connection lost on {}'.format(self.host))
    print(exc)
    # AND HERE
    asyncio.async(self.start_connection())


ssh1 = SshConnectManager(settings.host, settings.username, settings.password, settings.port)

asyncio.get_event_loop().run_until_complete(...)

但我不明白为什么协同程序装饰器不能返回名为decorator。(这让我很困惑,我把这和扭曲的回调混淆了)。

我发现了如何记住这一点,有一个简单的例子,如果start_connection可以得到参数:

@asyncio.coroutine
def start_connection(self, some_arg):
    pass

所以,我可以简单地写下:

asyncio.async(self.start_connection(some_val))

并且不需要在asyncio.async函数中创建其他属性

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