如何解决使用带有 asyncpg db 的 apscheduler 作为作业存储:错误 MissingGreenlet
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,所以我什至不知道该用谷歌搜索什么。
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
错误信息和回溯:
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",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
我查找了提供的链接,但没有了解它。所以如果有人能告诉我发生了什么,那将是很好的,这样我就可以自己寻找解决方案。 (解决方案也可以,当然xD)
抱歉这个“开放性”问题,但我的理解太糟糕了,我不知道该问什么。
解决方法
我认为问题出在 ApScheduler 中。
发生的事情是 scheduler.start()
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 +asyncpg
并且当 ApScheduler 尝试创建表时没有运行异步协程(即:async def
)。因此,“从未等待过协程‘连接’”错误。
阅读 ApScheduler 代码后,我认为“与 asyncio 集成”有点误导 - 特别是 scheduler 可以运行 asyncio,但 JobStore 本身没有提供 asyncio 数据库连接。 >
您可以通过删除与 ApScheduler 一起使用的连接 url 中的 +asyncpg
来使其工作。
请注意,仍然可以通过单独的 asyncpg 连接在作业函数中使用异步数据库调用。
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