revington

var earth_radius = 6371;

function toRadian(x) {
    return x * (Math.PI / 180);
}

function diffRadian(v1, v2) {
    return toRadian(v2) - toRadian(v1);
}

revington

var cradle = require('cradle');

var database = 'app';

cradle.setup({
    host: '127.0.0.1',
    port: 5984,
    auth: { username: "YOUR_USERNAME", password: "YOUR_PASSWORD" }
});

revington

module.exports.process = function () {
    var f = arguments;
    return function (initialContext) {
        var ctx = initialContext || {},
            i = 0,
            walk = function () {
                return f[i++] ||
                function () {
                    throw new Error('can not "next()"');
                };

revington

var amqp = require('amqp'),
    debug = require('debug')('master:' + process.pid), time= 10;
debug('hello');
var connection = amqp.createConnection({
    host: 'localhost'
});
var exc;
connection.on('ready', function () {
     exc = connection.exchange('my-exchange', {
        type: 'fanout'

revington

ssh -Ni ./my_key.pem -L 5984:127.0.0.1:5984 ec2-user@xxxxxxamazon-instance.compute.amazonaws.com

revington

#!/usr/bin/env sh
trap 'killall' INT

killall() {
    trap '' INT TERM     # ignore INT and TERM while shutting down
    echo "**** Shutting down... ****"     # added double quotes
    kill -TERM 0         # fixed order, send TERM not INT
    wait
    echo DONE
}

revington

#!/bin/bash                                                               
                                                                          
while read  -r line; do                                                   
  curl -X DELETE http://localhost:5984/$line                              
done  < <( curl http://localhost:5984/_all_dbs  2> /dev/null |  node -e " 
process.stdin.setEncoding('utf8');                                        
process.stdin.resume();                                                   
var buf = '';                                                             
process.stdin.on('data', function(chunk){                                 
  buf += chunk;                                                           

revington

#!/bin/bash
export IP=$(/sbin/ifconfig eth0 | grep 'inet addr:' | cut -d: -f2 | awk '{ print $1}')
echo "setting up ip ${IP}"

check_service(){
  echo `upnpc -l | grep $1'->' | grep -oE "\b([0-9]{1,3}\.){3}[0-9]{1,3}\b"`
}

register(){
  local service_name=$1

revington

"use strict";
var express = require('express'),
    nano = require('nano'),
    path = require('path'),
    compression = require('compression'),
    favicon = require('serve-favicon'),
    logger = require('morgan'),
    cookieParser = require('cookie-parser'),
    session = require('express-session'),
    bodyParser = require('body-parser'),

revington

#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?