steven burningsky250

rabbitmq exchange type:

direct:

when a queue is bound to this exchange with a specific routing_key(rk), messages coming into the exchange with topic of the same with the routing_key(rk) will be pushed into the queue. if there are multiple queues bound with the same routing key, the message will be fan-outed to all the queues.
fan-out

when a queue is bound to this exchange, whatever the routing key is specified, a message coming into the exchange will be fan-outed to the queue.
topic

1. network

fping: fast&concurrent ping to multiple hosts
jq: json parse in structured way

source： https://stackoverflow.com/questions/34695052/how-is-django-persistent-database-connections-thread-safe

The ConnectionHandler is not a connection -- it only handles connections. It does so in a perfectly thread-safe manner by storing them on self._connections, which is a thread.local instance. The ConnectionHandler overrides getitem to support thread-local connections. When you access connections['default'], it looks if the default attribute exists on self._connections, which is a thread local. If it does, that would be the connection to the default database for the current thread. If it doesn't, it'll create a new one and set it on self._connections. Other threads won't be able to access this connection, since it's set on a thread local object. In the end it pretty much comes down to the public API. Setting a ConnectionHandler on a thread-local object would work as well, but the public API would be more complicated than it currently is, since user code would manually need to check if the

comparison with many ways to construct a big list:

list repeat

python -m timeit -n 10 -r 10 -v '[0]*10000000'
raw times: 0.561 0.528 0.519 0.516 0.516 0.557 0.516 0.513 0.516 0.509
10 loops, best of 10: 50.9 msec per loop

hint: create python object 'int' once, repeat it 10,000,000 times.

	package main

	import (
	"fmt"
	"runtime"
	)

	// reference: https://stackoverflow.com/questions/28432658/does-go-garbage-collect-parts-of-slices/28432812#28432812
	func main() {
	manyBigSlices := make([][]int, 10)

	use std::thread::{self, sleep};
	use std::time::Duration;

	#[tokio::test]
	async fn test_async_call_sync() {
	fn sync_dummy_func() -> i32 {
	sleep(Duration::from_secs(1));
	1
	}

	// reference: https://go.dev/ref/mem#chan
	package main

	import (
	"fmt"
	"sync"
	"testing"
	)

	func TestChan(t *testing.T) {

	#!/bin/bash
	# bash generate random alphanumeric string
	#

	# bash generate random 32 character alphanumeric string (upper and lowercase) and
	NEW_UUID=$(cat /dev/urandom \| tr -dc 'a-zA-Z0-9' \| fold -w 32 \| head -n 1)

	# bash generate random 32 character alphanumeric string (lowercase only)
	cat /dev/urandom \| tr -dc 'a-zA-Z0-9' \| fold -w 32 \| head -n 1

	# Autoreloading launcher.
	# Borrowed from Peter Hunt and the CherryPy project (https://cherrypy.org/).
	# Some taken from Ian Bicking's Paste (http://pythonpaste.org/).
	#
	# Portions copyright (c) 2004, CherryPy Team (team@cherrypy.org)
	# All rights reserved.
	#
	# Redistribution and use in source and binary forms, with or without modification,
	# are permitted provided that the following conditions are met:
	#

	import sys
	import os
	print os.path.join(sys.prefix, "lib","python" + sys.version[:3])