Rocky Madden rockymadden

Update, September 2016

OK, you can pretty much ignore what I wrote below this update, because it doesn't really apply anymore.

I wrote this over a year ago, and at the time I had spent a couple of weeks trying to get Kafka 0.8 working with .NET and then Node.js with much frustration and very little success. I was rather angry. It keeps getting linked, though, and just popped up on Hacker News, so here's sort of an update, although I haven't used Kafka at all this year so I don't really have any new information.

In the end, we managed to get things working with a Node.js client, although we continued to have problems, both with our code and with managing a Kafka/Zookeeper cluster generally. What made it worse was that I did not then, and do not now, believe that Kafka was the correct solution for that particular problem at that particular company. What they were trying to achieve could have been done more simply with any number of other messaging systems, with a subscriber reading messages off and writing

What is the appeal of dynamically-typed languages?

Kris Nuttycombe asks:

I genuinely wish I understood the appeal of unityped languages better. Can someone who really knows both well-typed and unityped explain?

I think the terms well-typed and unityped are a bit of question-begging here (you might as well say good-typed versus bad-typed), so instead I will say statically-typed and dynamically-typed.

I'm going to approach this article using Scala to stand-in for static typing and Python for dynamic typing. I feel like I am credibly proficient both languages: I don't currently write a lot of Python, but I still have affection for the language, and have probably written hundreds of thousands of lines of Python code over the years.

How to create a maven repository for your github project step by step

Clone your project in a separate folder

(note: replace ORGANIZATION and PROJECT)

git clone git clone [email protected]:ORGANIZATION/PROJECT.git my-repository

Cd into it

The 0.13.0 improvements to React Components are often framed as "es6 classes" but being able to use the new class syntax isn't really the big change. The main thing of note in 0.13 is that React Components are no longer special objects that need to be created using a specific method (createClass()). One of the benefits of this change is that you can use the es6 class syntax, but also tons of other patterns work as well!

Below are a few examples creating React components that all work as expected using a bunch of JS object creation patterns (https://github.com/getify/You-Dont-Know-JS/blob/master/this%20&%20object%20prototypes/ch4.md#mixins). All of the examples are of stateful components, and so need to delegate to React.Component for setState(), but if you have stateless components each patterns tends to get even simpler. The one major caveat with react components is that you need to assign props and context to the component instance otherwise the component will be static. The reason is

	trait λ {
	type α
	}

	trait Functor extends λ {
	type α <: λ

	def map[A,B](x: α { type α = A })(f: A => B): α { type α = B }
	}

	# You don't need Fog in Ruby or some other library to upload to S3 -- shell works perfectly fine
	# This is how I upload my new Sol Trader builds (http://soltrader.net)
	# Based on a modified script from here: http://tmont.com/blargh/2014/1/uploading-to-s3-in-bash

	S3KEY="my aws key"
	S3SECRET="my aws secret" # pass these in

	function putS3
	{
	path=$1

	/* @flow */

	var React = require("react")
	var Immutable = require("immutable")

	// In order to use any type as props, including Immutable objects, we
	// wrap our prop type as the sole "data" key passed as props.
	type Component<P> = ReactClass<{},{ data: P },{}>
	type Element = ReactElement<any, any, any>

	echo "Flipping tables! (╯°□°）╯︵ ┻━┻"

	num_rules=3

	real=3 # exposed to the ELB as port 443
	test=4 # used to install test certs for domain verification
	health=5 # used by the ELB healthcheck

	blue_prefix=855
	green_prefix=866

	val n = 9
	val s = Math.sqrt(n).toInt
	type Board = IndexedSeq[IndexedSeq[Int]]

	def solve(board: Board, cell: Int = 0): Option[Board] = (cell%n, cell/n) match {
	case (r, `n`) => Some(board)
	case (r, c) if board(r)(c) > 0 => solve(board, cell + 1)
	case (r, c) =>
	def guess(x: Int) = solve(board.updated(r, board(r).updated(c, x)), cell + 1)
	val used = board.indices.flatMap(i => Seq(board(r)(i), board(i)(c), board(s(r/s) + i/s)(s(c/s) + i%s)))

	#!/bin/bash

	socat -v -T0.05 tcp-l:8081,reuseaddr,fork system:"echo 'HTTP/1.1 200 OK'; echo 'Connection: close'; echo; cat"