Miikka Tuominen tuommii

Digital Ocean DevOps Cheatsheet (Ubuntu 16.04)

How to Deploy a Node.js App with SSL

Create an SSH key

We will need this for our server configuration

Open console

Golang Workers / Job Queue

A running example of the code from:

This gist creates a working example from blog post, and a alternate example using simple worker pool.

TLDR: if you want simple and controlled concurrency use a worker pool.

INTRO

Concurrency is a domain I have wanted to explore for a long time because the locks and the race conditions have always intimidated me. I recall somebody suggesting concurrency patterns in golang because they said "you share the data and not the variables".

Amused by that, I searched for "concurrency in golang" and bumped into this awesome slide by Rob Pike: https://talks.golang.org/2012/waza.slide#1 which does a great job of explaining channels, concurrency patterns and a mini-architecture of load-balancer (also explains the above one-liner).

Let's dig in:

Goroutines

Virtual Hosts on nginx (CSC309)

When hosting our web applications, we often have one public IP address (i.e., an IP address visible to the outside world) using which we want to host multiple web apps. For example, one may wants to host three different web apps respectively for example1.com, example2.com, and example1.com/images on the same machine using a single IP address.

How can we do that? Well, the good news is Internet browsers

	#include <stdbool.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <unistd.h>

	#include <linux/input.h>
	#include <fcntl.h>

	#include <stdarg.h>
	#include <stdint.h>

	#!/bin/sh
	repo_name=$1
	test -z $repo_name && echo "Repo name required." 1>&2 && exit 1
	curl -u '[username]:[password]' https://api.github.com/user/repos -d "{\"name\":\"$repo_name\"}"
	git init
	git add .
	git commit -m "initial commit"
	git remote add origin "https://github.com/[username]/$repo_name.git"
	git push -u origin master

	syntax on
	set number
	set noswapfile
	set nocompatible

	set autoindent
	set backspace=indent,eol,start
	set complete-=i
	set smarttab
	set tabstop=4

	package main

	import (
	"fmt"
	"github.com/gorilla/mux"
	"github.com/gorilla/securecookie"
	"net/http"
	)

	// cookie handling

	groupBy(data, unwindKey, calcKey) {
	let output = {};

	// function that we call each item in data
	let sum = function(row, index) {
	// if not found lets add it to output
	if (!(row[unwindKey] in output)) {
	output[row[unwindKey]] = row[calcKey];
	}
	// Muutoin lasketaan summa