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?

stevesun21

import com.datastax.driver.core.*;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

/**
 * This is a helper class for implementing a pagination function based on Cassandra Java Driver (http://datastax.github.io/java-driver/)
 *
 * The solution of skipping rows is that use page state rather than iterator rows one by one.

aioutecism

Set up a VPN Server (PPTP) on AWS

1. Create a EC2 instance using Ubuntu 14.04.
2. In Secure Group Inbound Rules, add a SSH Rule(TCP, Port 22, 0.0.0.0/0) and a Custom TCP Rule(TCP, Port 1723, 0.0.0.0/0).
3. Optional: Associate a Elastic IP with the instance.
4. SSH into the instance.
5. sudo apt-get install pptpd.
6. sudo vim /etc/pptpd.conf. Uncomment localip 192.168.0.1 and remoteip 192.168.0.234-238,192.168.0.245.
7. sudo vim /etc/ppp/pptpd-options. Uncomment ms-dns and ms-wins. Change the IP to Google's DNS like this:

Abizern

//
//  LoggingPrint.swift
//

import Foundation

/**
 Prints the filename, function name, line number and textual representation of `object` and a newline character into
 the standard output if the build setting for "Active Complilation Conditions" (SWIFT_ACTIVE_COMPILATION_CONDITIONS) defines `DEBUG`.

srid

#!/bin/bash -ex
# Wrapper for 'docker save' fixing,
# https://github.com/dotcloud/docker/issues/3877
# In addition: this script will always save exactly one image (possibly
# multiple tags).

IMAGE=$1
TARGET=$2
NAME=`echo $IMAGE | awk -F':' '{print $1}'`
ID=`docker inspect $IMAGE | python -c "import sys,json; print json.load(sys.stdin)[0]['id']"`

ryandotsmith

FROM ubuntu
MAINTAINER "Bobby Wilson"
RUN apt-get update
RUN apt-get install curl -y
RUN cd /usr/local; curl -O http://nodejs.org/dist/v0.10.16/node-v0.10.16-linux-x64.tar.gz
RUN cd /usr/local; tar xzf node-v0.10.16-linux-x64.tar.gz
ENV PATH /usr/local/bin:/usr/sbin:/bin:/usr/local/node-v0.10.16-linux-x64/bin
ADD . /app
EXPOSE 8000:8000
ENV PORT 8000

dergachev

OS X Screencast to animated GIF

This gist shows how to create a GIF screencast using only free OS X tools: QuickTime, ffmpeg, and gifsicle.

Instructions

To capture the video (filesize: 19MB), using the free "QuickTime Player" application:

orip

import java.lang.reflect.Type;

import android.util.Base64;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;

stevesun21

public class NumberWordingTranslator {

	private final static String[] hundredWords={
		"Zero", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine",
		"Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen",
		"Twenty", null, null, null, null, null, null, null, null, null,
		"Thirty", null, null, null, null, null, null, null, null, null,
		"Forty", null, null, null, null, null, null, null, null, null,
		"Fifty", null, null, null, null, null, null, null, null, null,
		"Sixty", null, null, null, null, null, null, null, null, null,

oodavid

Backup MySQL to Amazon S3

This is a simple way to backup your MySQL tables to Amazon S3 for a nightly backup - this is all to be done on your server :-)

Sister Document - Restore MySQL from Amazon S3 - read that next

1 - Install s3cmd

this is for Centos 5.6, see http://s3tools.org/repositories for other systems like ubuntu etc