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我正在尝试通过 asyncpg 连接将 Apscheduler 与 postgresql 数据库一起使用。我认为它会起作用，因为 asyncpg 支持 sqlalchemy ref。但是，是的，它不起作用。更糟糕的是，我不明白错误信息，所以我什至不知道要谷歌搜索什么。

import asyncio
from apscheduler.schedulers.asyncio import AsyncIOScheduler
from apscheduler.jobstores.sqlalchemy import SQLAlchemyJobStore

def simple_job():
    print('This was an easy job!')

scheduler = AsyncIOScheduler()
jobstore = SQLAlchemyJobStore(url='postgresql+asyncpg://user:password@localhost:5432/public')
scheduler.add_jobstore(jobstore)
# schedule a simple job
scheduler.add_job(simple_job, 'cron', second='15', id='heartbeat',
    coalesce=True, misfire_grace_time=5, replace_existing=True)
scheduler.start()

版本：

python 3.7
APScheduler==3.7.0
asyncpg==0.22.0
SQLAlchemy==1.4.3

错误消息和回溯：

Traceback (most recent call last):
  File "C:/Users/d/PycharmProjects/teamutils/utils/automation.py", line 320, in <module>
    scheduler.start()
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\apscheduler\schedulers\asyncio.py", line 45, in start
    super(AsyncIOScheduler, self).start(paused)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\apscheduler\schedulers\base.py", line 163, in start
    store.start(self, alias)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\apscheduler\jobstores\sqlalchemy.py", line 68, in start
    self.jobs_t.create(self.engine, True)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\sql\schema.py", line 940, in create
    bind._run_ddl_visitor(ddl.SchemaGenerator, self, checkfirst=checkfirst)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\engine\base.py", line 2979, in _run_ddl_visitor
    with self.begin() as conn:
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\engine\base.py", line 2895, in begin
    conn = self.connect(close_with_result=close_with_result)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\engine\base.py", line 3067, in connect
    return self._connection_cls(self, close_with_result=close_with_result)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\engine\base.py", line 91, in __init__
    else engine.raw_connection()
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\engine\base.py", line 3146, in raw_connection
    return self._wrap_pool_connect(self.pool.connect, _connection)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\engine\base.py", line 3113, in _wrap_pool_connect
    return fn()
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\pool\base.py", line 301, in connect
    return _ConnectionFairy._checkout(self)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\pool\base.py", line 755, in _checkout
    fairy = _ConnectionRecord.checkout(pool)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\pool\base.py", line 419, in checkout
    rec = pool._do_get()
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\pool\impl.py", line 145, in _do_get
    self._dec_overflow()
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\util\langhelpers.py", line 72, in __exit__
    with_traceback=exc_tb,
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\util\compat.py", line 198, in raise_
    raise exception
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\pool\impl.py", line 142, in _do_get
    return self._create_connection()
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\pool\base.py", line 247, in _create_connection
    return _ConnectionRecord(self)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\pool\base.py", line 362, in __init__
    self.__connect(first_connect_check=True)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\pool\base.py", line 605, in __connect
    pool.logger.debug("Error on connect(): %s", e)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\util\langhelpers.py", line 72, in __exit__
    with_traceback=exc_tb,
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\util\compat.py", line 198, in raise_
    raise exception
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\pool\base.py", line 599, in __connect
    connection = pool._invoke_creator(self)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\engine\create.py", line 578, in connect
    return dialect.connect(*cargs, **cparams)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\engine\default.py", line 548, in connect
    return self.dbapi.connect(*cargs, **cparams)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\dialects\postgresql\asyncpg.py", line 744, in connect
    await_only(self.asyncpg.connect(*arg, **kw)),
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\util\_concurrency_py3k.py", line 48, in await_only
    "greenlet_spawn has not been called; can't call await_() here. "
sqlalchemy.exc.MissingGreenlet: greenlet_spawn has not been called; can't call await_() here. Was IO attempted in an unexpected place? (Background on this error at: http://sqlalche.me/e/14/xd2s)
sys:1: RuntimeWarning: coroutine 'connect' was never awaited

我查看了提供的链接，但没有变得聪明。因此，如果有人能告诉我发生了什么，那就太好了，这样我就可以自己寻找解决方案。（当然，解决方案也可以，xD）

对不起这个“开放”的问题，但我的理解太糟糕了，我不知道该问什么。

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1 回答 1

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我认为问题出在 ApScheduler 中。

正在发生的事情是，scheduler.start()它将尝试在您的数据库中创建作业表。但是由于您的数据库 url 被指定为并且当 ApScheduler 尝试创建表时+asyncpg没有运行异步协程（即：）。async def因此，“从未等待协程‘连接’”错误。

阅读 ApScheduler 代码后，我认为“与 asyncio 集成”有点误导 - 特别是调度程序可以运行 asyncio，但 JobStore 本身没有提供 asyncio 数据库连接。

您可以通过删除+asyncpg与 ApScheduler 一起使用的连接 url 来使其正常工作。

请注意，仍然可以通过单独的 asyncpg 连接在作业函数中使用 async db 调用。

于 2021-03-30T18:45:15.593 回答