Pause the main thread during the execute callback function Question: I am trying to use page.on to listening certain event, and once it is triggered I want to use callback function to handle it and pause the main thread operation till the callback finished. How can I achieve that? So far it is what I …
What Actually Triggers the Asyncio Tasks? Question: Trying to understand python asyncio coming from some background on multithreading with concurrent.futures. Here is the sample script #!/usr/bin/env python3 # encoding: utf-8 """Sample script to test asyncio functionality.""" import asyncio import logging from time import sleep # noqa logging.basicConfig(format=’%(asctime)s | %(levelname)s: %(message)s’, level=logging.INFO) async def wait(i: int) …
Create task from within another running task Question: In Python I create two async tasks: tasks = [ asyncio.create_task(task1(queue)), asyncio.create_task(task2(queue)), ] await asyncio.gather(*tasks) Now, I have a need to create a third task "task3" within task1. So I have: async def task1(queue): # and here I need to create the "task3": asyncio.create_task(task3(queue)) # and how …
How to increase asyncio thread limits in an existing co-routine Question: I am currently working on a program using concurrency with asyncio. The code here is over simplified in order to show the problem. It is runnable without any dependencies if you need so. You have two tasks levels: 1: One in operation_loop which creates …
Spawning a new process with an asyncio loop from within the asyncio loop running in the current process Question: I’m a little confused about the interaction between multiprocessing and asyncio. My goal is to be able to spawn async processes from other async processes. Here is a small example: import asyncio from multiprocessing import Process …
How to DRY up this psycopg connection pool boilerplate code with a reusable async function or generator? Question: I’m using psycopg to connect to a PostgreSQL database using a connection pool. It works great, but any function that needs to run SQL in a transaction gets three extra layers of nesting: /app/db.py from os import …
'[WinError 10022] An invalid argument was supplied' when using Python asyncio.loop.create_datagram_endpoint and IPv6 Question: When I execute the following script I get Send: Hello World! Error received: [WinError 10022] An invalid argument was supplied Error received: [WinError 10022] An invalid argument was supplied Connection closed import asyncio import socket class EchoClientProtocol: def __init__(self, message, on_con_lost): …
Asyncio with 2 websockets Question: I trying to maintain 2 websockets connection open at the same time and have them send their response to a third async function, but I can’t seem to get it to work. async def checking(): while True: print(‘Im here.’) await asyncio.sleep(3) async def public_handler(response): if type(response) == list: print(response[1]) await …
Asyncio subprocess is not being cancelled properly on interrupt Question: I have the following code that doesn’t work the way I expected it to. I wanted to be able to interrupt my program with SIGINT (Ctrl-C). It should then cancel tasks that run subprocesses and run some code upon cancellation, but I can’t get that …
How to handle "coroutine never awaited" as an exception? Question: There are many answers about how to ignore or fix this, but what I need is a solution that would handle these, because we have a huge project and something like this is bound to happen, but it’s silent and therefore goes unnoticed for some …
