Jonhnny Weslley jweslley

A slightly updated version of this doc is here on my website.

Why I Like Go

I visited with PagerDuty yesterday for a little Friday beer and pizza. While there I got started talking about Go. I was asked by Alex, their CEO, why I liked it. Several other people have asked me the same question recently, so I figured it was worth posting.

Goroutines

The first 1/2 of Go's concurrency story. Lightweight, concurrent function execution. You can spawn tons of these if needed and the Go runtime multiplexes them onto the configured number of CPUs/Threads as needed. They start with a super small stack that can grow (and shrink) via dynamic allocation (and freeing). They are as simple as go f(x), where f() is a function.

SSH agent forwarding and screen

When connecting to a remote server via SSH it is often convenient to use SSH agent forwarding so that you don't need a separate keypair on that server for connecting to further servers.

This is enabled by adding the

ForwardAgent yes

option to any of your Host entries in ~/.ssh/config (or alternatively with the -A option). Don't set this option in a wildcard Host * section since any user on the remote server that can bypass file permissions can now als use keys loaded in your SSH agent. So only use this with hosts you trust.

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

Clarify and agree on the scope of the system

User cases (description of sequences of events that, taken together, lead to a system doing something useful)
- Who is going to use it?
- How are they going to use it?

	// Copyright 2013 René Kistl. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	package srpc

	import (
	"errors"
	"fmt"
	"github.com/pcdummy/skynet2/rpc/bsonrpc"

	package main
	import (
	"./binding"
	"fmt"
	)

	func main() {
	binding.PrintHello()
	binding.Seed(1)
	fmt.Println(binding.Random())

	web:
	build: .
	volumes:
	- .:/opt/myapp
	ports:
	- '3000:3000'
	links:
	- db
	- redis
	- selenium

	javascript:(function() {

	function copyToClipboard(text) {
	if (window.clipboardData && window.clipboardData.setData) {
	/IE specific code path to prevent textarea being shown while dialog is visible./
	return clipboardData.setData("Text", text);

	} else if (document.queryCommandSupported && document.queryCommandSupported("copy")) {
	var textarea = document.createElement("textarea");
	textarea.textContent = text;

	// you need to use https://github.com/digitalbazaar/forge

	const encryptData = (key, data) => {
	const mdKey = forge.md.sha256.create()
	mdKey.update(key)

	const iv = forge.random.getBytesSync(12)

	const cipher = forge.cipher.createCipher('AES-GCM', mdKey.digest())
	cipher.start({

	gem 'stackprof', require: false
	gem 'ruby-prof', require: false