Add check for asyncio event loop to remain the same

This commit is contained in:
Lonami Exo 2023-05-24 19:15:46 +02:00
parent 6a7a981b7a
commit 16122545ec
3 changed files with 50 additions and 0 deletions

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@ -261,6 +261,46 @@ same session anywhere else. If you need to use the same account from
multiple places, login and use a different session for each place you need.
What does "The asyncio event loop must not change after connection" mean?
=========================================================================
Telethon uses ``asyncio``, and makes use of things like tasks and queues
internally to manage the connection to the server and match responses to the
requests you make. Most of them are initialized after the client is connected.
For example, if the library expects a result to a request made in loop A, but
you attempt to get that result in loop B, you will very likely find a deadlock.
To avoid a deadlock, the library checks to make sure the loop in use is the
same as the one used to initialize everything, and if not, it throws an error.
The most common cause is ``asyncio.run``, since it creates a new event loop.
If you ``asyncio.run`` a function to create the client and set it up, and then
you ``asyncio.run`` another function to do work, things won't work, so the
library throws an error early to let you know something is wrong.
Instead, it's often a good idea to have a single ``async def main`` and simply
``asyncio.run()`` it and do all the work there. From it, you're also able to
call other ``async def`` without having to touch ``asyncio.run`` again:
.. code-block:: python
# It's fine to create the client outside as long as you don't connect
client = TelegramClient(...)
async def main():
# Now the client will connect, so the loop must not change from now on.
# But as long as you do all the work inside main, including calling
# other async functions, things will work.
async with client:
....
if __name__ == '__main__':
asyncio.run(main())
Be sure to read the ``asyncio`` documentation if you want a better
understanding of event loop, tasks, and what functions you can use.
What does "bases ChatGetter" mean?
==================================

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@ -399,6 +399,7 @@ class TelegramBaseClient(abc.ABC):
self._borrowed_senders = {}
self._borrow_sender_lock = asyncio.Lock()
self._loop = None # only used as a sanity check
self._updates_error = None
self._updates_handle = None
self._keepalive_handle = None
@ -535,6 +536,11 @@ class TelegramBaseClient(abc.ABC):
if self.session is None:
raise ValueError('TelegramClient instance cannot be reused after logging out')
if self._loop is None:
self._loop = helpers.get_running_loop()
elif self._loop != helpers.get_running_loop():
raise RuntimeError('The asyncio event loop must not change after connection (see the FAQ for details)')
if not await self._sender.connect(self._connection(
self.session.server_address,
self.session.port,

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@ -30,6 +30,10 @@ class UserMethods:
return await self._call(self._sender, request, ordered=ordered)
async def _call(self: 'TelegramClient', sender, request, ordered=False, flood_sleep_threshold=None):
if self._loop is not None and self._loop != helpers.get_running_loop():
raise RuntimeError('The asyncio event loop must not change after connection (see the FAQ for details)')
# if the loop is None it will fail with a connection error later on
if flood_sleep_threshold is None:
flood_sleep_threshold = self.flood_sleep_threshold
requests = (request if utils.is_list_like(request) else (request,))