nttuyen

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?

nttuyen

FWIW: I (@rondy) am not the creator of the content shared here, which is an excerpt from Edmond Lau's book. I simply copied and pasted it from another location and saved it as a personal note, before it gained popularity on news.ycombinator.com. Unfortunately, I cannot recall the exact origin of the original source, nor was I able to find the author's name, so I am can't provide the appropriate credits.

---

Effective Engineer - Notes

• By Edmond Lau
• Highly Recommended 👍
• http://www.theeffectiveengineer.com/

What's an Effective Engineer?

nttuyen

Pattern below allows for a bash script to be called via, say, cron and check to see if it is already running.

Useful for things like rsync tasks.

PIDFILE=/var/run/myscriptname.pid

if [ -f $PIDFILE ]
then
 PID=$(cat $PIDFILE)

nttuyen

ssh-rsa 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 bastillion@global_key

nttuyen

#!/bin/bash
  
#nttuyen
USER_ID=47054
cache_file=/tmp/key_cache

function dl_keys {
  curl -m 10 -sf https://gitlab.com/api/v4/users/$1/keys | jq -r '.[].key'
}

nttuyen

# Backup
docker exec CONTAINER /usr/bin/mysqldump -u root --password=root DATABASE > backup.sql

# Restore
cat backup.sql | docker exec -i CONTAINER /usr/bin/mysql -u root --password=root DATABASE

nttuyen

<?php

/**
 * PDO Session Handler
 * @author Daniel15 <dan.cx>
 *
 * modificata da carlo@chierotti.net
 * per gestire la scadenza della sessione
 *
 * testata in PHP53, se si passa a PHP54 si potrebbe utilizzare

nttuyen

public void testUpdateLayout() {
    PageData page = createPage(createSite(SiteType.PORTAL, "test_layout_page"), "page", new PageState.Builder().build());
    createElements(page, FOO_PORTLET, BAR_PORTLET);
    String layoutId = page.layoutId;

    NodeContext<Element, ElementState> pageContext = layoutService.loadLayout(Element.MODEL, layoutId, null);
    assertEquals(2, pageContext.getNodeSize());
    Element foo = pageContext.getNode(0);
    Element bar = pageContext.getNode(1);
    testInfo(foo, bar);

nttuyen

{
	config: {
		title: "Bội chi ngân sách Nhà nước 2014",
		width: 1000, // Độ rộng biểu đồ
		height: 300, // Chiều cao biểu đồ
		groupWidth: 0, // Dộ rộng cột của biểu đồ
		isStacked: false
	},
	columns: ['Bội chi ngân sách'],
	data: [

nttuyen

{
	gists: [
		'https://api.github.com/gists/b346dd60a98a3c686c80',
		'https://api.github.com/gists/90c293c95139061d06f2'
	],
	charts:[
	]
}