Zack schollz

Easy parallel python with concurrent.futures

As of version 3.3, python includes the very promising concurrent.futures module, with elegant context managers for running tasks concurrently. Thanks to the simple and consistent interface you can use both threads and processes with minimal effort.

For most CPU bound tasks - anything that is heavy number crunching - you want your program to use all the CPUs in your PC. The simplest way to get a CPU bound task to run in parallel is to use the ProcessPoolExecutor, which will create enough sub-processes to keep all your CPUs busy.

We use the context manager thusly:

with concurrent.futures.ProcessPoolExecutor() as executor:

Docker - How to cleanup (unused) resources

Once in a while, you may need to cleanup resources (containers, volumes, images, networks) ...

delete volumes

// see: https://github.com/chadoe/docker-cleanup-volumes

$ docker volume rm $(docker volume ls -qf dangling=true)

$ docker volume ls -qf dangling=true | xargs -r docker volume rm

c:\dev\go-sandbox\jsonstore>go test -bench . -count 10
goos: windows
goarch: amd64
BenchmarkJsonstore-4        2000            897051 ns/op
BenchmarkJsonstore-4        2000            885050 ns/op
BenchmarkJsonstore-4        2000           1131564 ns/op
BenchmarkJsonstore-4        2000            839048 ns/op
BenchmarkJsonstore-4        2000            919052 ns/op
BenchmarkJsonstore-4        2000            838547 ns/op

	DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
	Version 2, December 2004

	Copyright (C) 2011 Olivier Scherrer

	Everyone is permitted to copy and distribute verbatim or modified
	copies of this license document, and changing it is allowed as long
	as the name is changed.

	DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE

	#!/usr/bin/env bash

	# Check we've got command line arguments
	if [ -z "$*" ] ; then
	echo "Need to specify ssh options"
	exit 1
	fi

	# Start trying and retrying
	((count = 100))

	// haversin(θ) function
	func hsin(theta float64) float64 {
	return math.Pow(math.Sin(theta/2), 2)
	}

	// Distance function returns the distance (in meters) between two points of
	// a given longitude and latitude relatively accurately (using a spherical
	// approximation of the Earth) through the Haversin Distance Formula for
	// great arc distance on a sphere with accuracy for small distances
	//

	// To the extent possible under law, the Yawning Angel has waived all copyright
	// and related or neighboring rights to orhttp_example, using the creative
	// commons "cc0" public domain dedication. See LICENSE or
	// <http://creativecommons.org/publicdomain/zero/1.0/> for full details.

	package main

	import (
	// Things needed by the actual interface.
	"golang.org/x/net/proxy"

	{0: 'tench, Tinca tinca',
	1: 'goldfish, Carassius auratus',
	2: 'great white shark, white shark, man-eater, man-eating shark, Carcharodon carcharias',
	3: 'tiger shark, Galeocerdo cuvieri',
	4: 'hammerhead, hammerhead shark',
	5: 'electric ray, crampfish, numbfish, torpedo',
	6: 'stingray',
	7: 'cock',
	8: 'hen',
	9: 'ostrich, Struthio camelus',

	import threading
	import time

	class TTLDict(dict):
	""" A dictionary with keys having specific time to live """

	def __init__(self, ttl=5):
	self._ttl = ttl
	# Internal key mapping keys of _d
	# to times of access