How to send a telegram message without blocking main thread

Question

from telegram import Bot
import asyncio

TOKEN = "blah"
CHAT_ID = 1

async def send_message_async():
    message = "This is a test update from the bot!"
    bot = Bot(token=TOKEN)
    await bot.send_message(chat_id=CHAT_ID, text=message)
    print("Message sent successfully!")


async def main():

    print("Before sending message...")

    await send_message_async()

    print("After sending message...") # I don't want this to be blocked until the message is sent


if __name__ == "__main__":
    asyncio.run(main())

I'm trying to send message without blocking whole thread, but I'm struggling to avoid it. Is there any way?

I am hoping to find a simpler API to above problem. Something like below

def send_message():
    # Sends message to user asynchonously without blocking the main thread
    pass

def main():
    # Main function
    send_message()

But it seems like, to call one async function, every other function should be converted into async function.

Answer 1

If you don't want to wait then don't use await but create_task()

task = asyncio.create_task(send_message_async())

You can use await task at the end of program to check if you may exit program
or you have to wait for end of this task.

# wait for end of task
await task
# or 
result = await task

You may also use if task.done(): to check it without blocking code.

if task.done():
    result = await task
else:
    # ...

---

from telegram import Bot
import asyncio

TOKEN = "blah"
CHAT_ID = 1

async def send_message_async():
    print('starting send_message_async()')
    message = "This is a test update from the bot!"
    #bot = Bot(token=TOKEN)
    #await bot.send_message(chat_id=CHAT_ID, text=message)
    await asyncio.sleep(3)
    print("Message sent successfully!")

async def main():

    print("Before sending message...")

    task = asyncio.create_task(send_message_async())
    #await send_message_async()

    print("After sending message...")

    await asyncio.sleep(6)

    print("End...")

    # wait for end of task (to makes sure it finished)
    await task

if __name__ == "__main__":
    asyncio.run(main())

---

Example with more print() to show that functions run at the same time.

from telegram import Bot
import asyncio

TOKEN = "blah"
CHAT_ID = 1

async def send_message_async():
    print('starting send_message_async()')
    message = "This is a test update from the bot!"
    #bot = Bot(token=TOKEN)
    #await bot.send_message(chat_id=CHAT_ID, text=message)
    
    for i in range(10):
        print('sending', i)
        await asyncio.sleep(0.5)
        
    print("Message sent successfully!")

    return "It's done!"

async def main():

    print("main: Before sending message...")

    task = asyncio.create_task(send_message_async())
    #await send_message_async()
    await asyncio.sleep(0.01)
    #print(dir(task)) # 
    
    print("main: After sending message...")

    for i in range(3):
        print('main', i)
        await asyncio.sleep(0.5)

    print("main: End")

    while not task.done():
        print('main: waiting for end of task')
        await asyncio.sleep(1)

    # wait for end of task
    #await task 
    result = await task  # if function use `return` to send result
    print('main: result:', result)
        
if __name__ == "__main__":
    asyncio.run(main())

Result:

main: Before sending message...
starting send_message_async()
sending 0
main: After sending message...
main 0
sending 1
main 1
sending 2
main 2
sending 3
main: End
main: waiting for end of task
sending 4
sending 5
main: waiting for end of task
sending 6
sending 7
main: waiting for end of task
sending 8
sending 9
main: waiting for end of task
Message sent successfully!
main: result: It's done!