discord.py非异步函数发消息报错：Thread-1无事件循环

问题描述 #

开发Discord机器人时，在非异步函数check_time中尝试发送消息，触发以下错误：

RuntimeError: There is no current event loop in thread 'Thread-1'

错误栈如下：

Exception in thread Thread-1:
Traceback (most recent call last):
  File "C:\Users\LENOVO\AppData\Local\Programs\Python\Python38\lib\threading.py", line 932, in _bootstrap_inner
    self.run()
  File "C:\Users\LENOVO\AppData\Local\Programs\Python\Python38\lib\threading.py", line 870, in run
    self._target(*self._args, **self._kwargs)
  File "c:/Users/LENOVO/Documents/Ada-online/Discord bot/main copy.py", line 19, in check_time
    asyncio.get_event_loop().create_task(channel.send("example message"))
  File "C:\Users\LENOVO\AppData\Local\Programs\Python\Python38\lib\asyncio\events.py", line 639, in get_event_loop
    raise RuntimeError('There is no current event loop in thread %r.'
RuntimeError: There is no current event loop in thread 'Thread-1'

完整代码：

import discord
import threading
import datetime
import time
import asyncio

intents = discord.Intents.default()
intents.message_content = True

client = discord.Client(intents=intents)

my_secret = 'bot_key'


def check_time():
    time.sleep(10)
    channel = client.get_channel(1027207022132863036)
    print('Channel:', channel)
    asyncio.get_event_loop().create_task(channel.send("example message"))
    while True:
        ndt = datetime.datetime.now()
        if ndt.strftime('%A') == 'Friday' and ndt.hour == 16 and ndt.minute == 29 and ndt.second == 5:
            asyncio.get_event_loop().create_task(channel.send("example message"))
        time.sleep(0.9)
        

@client.event
async def on_ready():
    print('We have logged in as {0.user}'.format(client))

@client.event
async def on_message(msg):
    print(msg.channel)
    msg_words1 = msg.content.split(' ')
    msg_words = []
    for i in msg_words1:
        msg_words.append(i.lower())


    if msg.author == client.user:
        return

    if ('zoom' in msg_words and 'when' in msg_words) or ('zoom' in msg_words and 'when?' in msg_words) or ('zoom?' in msg_words and 'when' in msg_words):
        await msg.channel.send('We have zoom every day from 16:00 to 17:30.')

t = threading.Thread(target=check_time)
t.start()

client.run(my_secret)

错误原因 #

discord.py的客户端运行在主线程的asyncio事件循环中，手动创建的子线程Thread-1没有绑定任何事件循环，直接调用asyncio.get_event_loop()会找不到可用的循环，导致报错。

解决方案 #

方案一：使用discord.py内置任务（推荐） #

放弃手动线程，改用discord.py提供的异步任务机制，将定时检查逻辑改为异步函数，完全在框架的事件循环内运行：

修改后的代码：

import discord
import datetime
import asyncio

intents = discord.Intents.default()
intents.message_content = True

client = discord.Client(intents=intents)

my_secret = 'bot_key'

async def check_time():
    await asyncio.sleep(10)  # 替换time.sleep为异步版本
    channel = client.get_channel(1027207022132863036)
    print('Channel:', channel)
    await channel.send("example message")
    while True:
        ndt = datetime.datetime.now()
        if ndt.strftime('%A') == 'Friday' and ndt.hour == 16 and ndt.minute == 29 and ndt.second == 5:
            await channel.send("example message")
        await asyncio.sleep(0.9)  # 替换time.sleep为异步版本

@client.event
async def on_ready():
    print('We have logged in as {0.user}'.format(client))
    # 启动定时任务
    asyncio.create_task(check_time())

@client.event
async def on_message(msg):
    print(msg.channel)
    msg_words = [i.lower() for i in msg.content.split(' ')]  # 简化列表处理

    if msg.author == client.user:
        return

    if ('zoom' in msg_words and 'when' in msg_words) or ('zoom' in msg_words and 'when?' in msg_words) or ('zoom?' in msg_words and 'when' in msg_words):
        await msg.channel.send('We have zoom every day from 16:00 to 17:30.')

client.run(my_secret)

方案二：保留线程，使用run_coroutine_threadsafe #

如果必须使用线程，通过asyncio.run_coroutine_threadsafe将发送消息的协程提交到主线程的事件循环执行：

修改后的check_time函数：

def check_time():
    time.sleep(10)
    channel = client.get_channel(1027207022132863036)
    print('Channel:', channel)
    # 提交协程到主线程的事件循环
    asyncio.run_coroutine_threadsafe(channel.send("example message"), client.loop)
    while True:
        ndt = datetime.datetime.now()
        if ndt.strftime('%A') == 'Friday' and ndt.hour == 16 and ndt.minute == 29 and ndt.second == 5:
            asyncio.run_coroutine_threadsafe(channel.send("example message"), client.loop)
        time.sleep(0.9)

注意：此方案需要确保client.loop已初始化（即客户端已完成启动），否则会触发额外错误。

内容的提问来源于stack exchange，提问作者Rok Kužner