vasanthk

System Design Cheatsheet

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

Basic Steps

1. 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?

lgg

#!/bin/bash

#Vars
web_service='nginx'
config_path='/usr/local/letssl/'
le_path='/opt/letsencrypt'
exp_limit=20;

#Func
function check_ssl {

sgnn7

echo '[Unit]
Description=High-performance, schema-free document-oriented database
After=syslog.target network.target
 
[Service]
User=mongodb
Group=mongodb
ExecStart=/usr/bin/mongod -f /etc/mongod.conf
 
[Install]

joepie91

Don't use VPN services.

No, seriously, don't. You're probably reading this because you've asked what VPN service to use, and this is the answer.

Note: The content in this post does not apply to using VPN for their intended purpose; that is, as a virtual private (internal) network. It only applies to using it as a glorified proxy, which is what every third-party "VPN provider" does.

• A Russian translation of this article can be found here, contributed by Timur Demin.
• A Turkish translation can be found here, contributed by agyild.
• There's also this article about VPN services, which is honestly better written (and has more cat pictures!) than my article.

xrstf

Let's Encrypt on Ubuntu 14.04, nginx with webroot auth

This document details how I setup LE on my server. Firstly, install the client as described on http://letsencrypt.readthedocs.org/en/latest/using.html and make sure you can execute it. I put it in /root/letsencrypt.

As it is not possible to change the ports used for the standalone authenticator and I already have a nginx running on port 80/443, I opted to use the webroot method for each of my domains (note that LE does not issue wildcard certificates by design, so you probably want to get a cert for www.example.com and example.com).

Configuration

For this, I placed config files into etc/letsencrypt/configs, named after <domain>.conf. The files are simple:

hootlex

##Windows users:

• Download wamp: http://www.wampserver.com/en/
• Download and extract cmder mini: https://github.com/cmderdev/cmder/releases/download/v1.1.4.1/cmder_mini.zip
• Update windows environment variable path to point to your php install folder (inside wamp installation dir) (here is how you can do this http://stackoverflow.com/questions/17727436/how-to-properly-set-php-environment-variable-to-run-commands-in-git-bash)

cmder will be refered as console

##Mac Os, Ubuntu and windows users continue here:

• Create a database locally named homestead utf8_general_ci

cmatskas

$git checkout –b temp #makes a new branch from current detached HEAD
$git branch –f master temp #update master to point to the new <temp> branch
$git branch –d temp #delete the <temp> branch
$git push origin master #push the re-established history

telekosmos

var uniqueArray = function(arrArg) {
  return arrArg.filter(function(elem, pos,arr) {
    return arr.indexOf(elem) == pos;
  });
};

var uniqEs6 = (arrArg) => {
  return arrArg.filter((elem, pos, arr) => {
    return arr.indexOf(elem) == pos;
  });

seanmavley

# What this command literally does is this:
# It iterates through directory in which the command is executed selecting .mp4 files only
# It then runs avconv command conversion on them
# See the parameters from avconv manual for details.
for i in *.mp4; do avconv -i "$i" -c:v h264 -crf 18 -c:a mp3 -r 30 "out-$i.mp4" ; done

dstroot

/**
 * World's simplest express server
 * - used to serve index.html from /public
 */

var express = require('express');
var serveStatic = require('serve-static');
var app = express();

app.use(serveStatic(__dirname + '/public'));