How would I send a message from another thread?

[Daanish-Khan]

I've got a bot that sends live updates to a channel. I've created a listener to obtain data, which is then processed and sent into it's respective discord channel. However, I am unable to send messages as it needs async, and creating a thread with async isn't working.

Asyncio has also proven to be difficult. I've tried asyncio.run_coroutine_threadsafe, which for some reason prevents the bot from processing commands. Creating a new event loop gives me Timeout context manager should be used inside a task.

Any ideas?

This is code below that is similar to what I have at the moment.

async def process_message(ctx):
    while True:
        if condition:
            continue
        else:
            # processing
            for key in channeldict:
                if key in title:
                    await ctx.guild.get_channel(channeldict[key]).send("test")

@client.command()
async def start_listening(ctx):
    thread = threading.Thread(target=process_message, args=[ctx])
    thread.start()

[Rapptz]

Please see the background task example for how to do this, alternatively if you need this to be wrapped in a prettier interface there's the ext.tasks extension that comes with the library.

[Daanish-Khan]

I've tried something similar with create_task, however it prevents the other commands from executing for whatever reason. I'll try using the example but I'm doubtful it works.

[Rapptz]

The reason why it's halting is because if condition is True in your example then it leads to an infinite loop without yielding back to the caller, see What does "blocking" mean? for more information there.

In order to play nicely with the asyncio system you have to yield back to the caller by using an await expression. So essentially:

import asyncio

async def never_ending():
    condition = False
    while True:
        if condition:
            # Never ending loop
            continue

        await do_work()
        condition = True

This function will never yield back to the caller when condition = True because it's a never ending loop.

If you want to do some co-operative work queue with a task you'll have to be a bit more involved using an asyncio.Queue. Note that this is true even if you use threading. Unfortunately I do not know enough about your situation to give you further assistance. However that's the crux of the issue here.