Nodejs Appliances On EmbeddedLinux

Node.
JS Appliances on
Embedded Linux Devices
Mehmet Fatih Karagöz & Cevahir Turgut
1
Outline
 Introduction to Node.js
 Cross-compiling Node.js and Node Package Manager(NPM)
 Development environment
 Scripting samples in embedded devices
 Development story of a surveillance application
 Demo
 Questions
2
Outline
 Cross-compiling Node.js and NPM
 Demo
 Questions
3
Introduction to Node.js
 What is Node.js?
 Node.js is a platform built on Chrome's JavaScript runtime
(V8) for easily building fast, scalable network applications.
 Event-Driven
 Non-Blocking I/O
 Lightweight
 Efficient HW Usage
4
Advantages Disadvantages
 Open source  Small Developer Pool

 HW Efficiency  Bad at CPU Bound Jobs
 Learning Curve  Asynchronous Debugging
 Development Time
 Javascript / No Compile
 NPM Package Manager
5
 What is learning curve?
 Node.JS uses Javascript
 Most web developers are familiar with the language
 You can get started with building very basic application in less
than one hour (that includes installation time!)
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 NPM (Node Packaged Modules)
 NodeJS package management system

 Install modules very easily even on embedded
 "npm install express“
 Installs dependant modules too
 Global install option
 "npm install -g express"
7
 Popular Modules
 Express
 Request
 Async
 Grunt
 socket.io
 Mocha
 Underscore
 Mongoose
 Redis
 Connect
8
Outline
 Demo
 Questions
9
Cross-compiling Node.js and NPM
 Where is Node.js?
 Download
 http://nodejs.org/download
 Git
 git clone git://github.com/joyent/node.git
 cd node
 git checkout v0.10
 Node.js is released under the MIT license.
10
 Configuration Options
 Usage: configure [options]
 Options:
 --without-npm Don't install the bundled npm package manager
 --without-ssl Build without SSL
 --without-snapshot Build without snapshotting V8 libraries. You
might want to set this for cross-compiling.
 --dest-cpu=DEST_CPU CPU architecture to build for.Valid values
are: arm, ia32, x64
 --dest-os=DEST_OS Operating system to build for.Valid values are:
win, mac, solaris, freebsd, openbsd, linux, android
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 How to make and install
 export AR=arm-linux-gnueabihf-ar
 export CC=arm-linux-gnueabihf-gcc
 export CXX=arm-linux-gnueabihf-g++
 export LINK=arm-linux-gnueabihf-g++
 ./configure --without-snapshot --dest-cpu=arm --dest-os=linux

 make
 make install DESTDIR=~/node-armhf/
12
Outline
 Demo
 Questions
13
Development Environment
 Suitable Editors
 Vim
 Gedit
 Webstorm
 Eclipse / Nodeclipse Plugin
 Cloud9 (Cloud based editor)
14
Development Environment
 “node debug myscript.js”
 Debugging Options
 cont, c - Continue execution
 next, n - Step next
 step, s - Step in
 out, o - Step out
 pause - Pause running code (like pause button in Developer Tools)
 setBreakpoint(), sb() - Set breakpoint on current line

 setBreakpoint(line), sb(line) - Set breakpoint on specific line
 setBreakpoint('fn()'), sb(...) - Set breakpoint on a first statement in functions body
 setBreakpoint('script.js', 1), sb(...) - Set breakpoint on first line of script.js
 clearBreakpoint, cb(...) - Clear breakpoint
 backtrace, bt - Print backtrace of current execution frame

 list(5) - List scripts source code with 5 line context (5 lines before and after)
 watch(expr) - Add expression to watch list
 unwatch(expr) - Remove expression from watch list
 watchers - List all watchers and their values (automatically listed on each breakpoint)
 repl - Open debugger's repl for evaluation in debugging script's context
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Outline
 Demo
 Questions
16
Scripting Samples in Embedded Devices
 GPIO/LED on/off
var exec = require(‘child_process’).exec;
17
 CPU / Memory Usage
var os = require(‘os’);
18
 Timers
19
 Ini Parser
config.ini:
;sample config ini file
name = Iniparser Demo
version = 0.1
“npm install iniparser”
20
Outline
 Demo
 Questions
21
Development Story of a Surveillance
Application - Overview
 Main Purpose
 Demonstrate usage scenario of Node.js in real world app
 Give more information about network classes of Node.js
 Run complete Node.js app in embedded platform
 Example Surveillance System

 Smart IP Cameras
 to detect motion, etc.
 Server PC
 at Command Control Center
 monitoring cameras, their alarms, etc.
22
 Deployment Model of Example System
23
 Used Components
 IGEPv2 Boards
 DM3730 Texas Instruments processor
 ARM Cortex A8 1GHz
 Camera ISP
 512 Megabytes RAM / 512 Megabytes FLASH
 Ethernet 10/100 MB BaseT
 And more (C64+ DSP 800MHz, 3D Accelerator SGX530 @ 200 MHz,
...)
 Kernel
 2.6.37
 Compiler:
 GCC version 4.6.3
24
 Component Diagram
25
 Component Diagram (with messages)
26
 Deployment Model of Example System
27
Application - Video App
 Video App
 Fake Applicaton to simulate motion detection
 Written using Boost CPP Libraries
 Connected to Camera System App with TCP
 Produces periodic alarm messages
 Receives configuration messages
28
Application - Video App
29
Application - Camera SystemMgr App
 Camera SystemMgr App
 Written using Node.js
 Manages other software elements running on camera through
IPC
 Store configurations
 Connection interface of camera to server
 Includes 2 TCP servers and 1 UDP client
 1 TCP Server for IPC with VideoApp
 1 TCP Server
 to get configuration messages from Server
 to send alarm messages to Server
 1 UDP broadcaster to send heartbeat
30
Camera SystemMgr App
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32
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Application - Server App
 Server App
 Connection with online cameras
 Camera discovery by listening Broadcast/UDP heartbeat messages
 Connecting TCP port of cameras
 Configuring cameras
 Collects alarms from cameras
 Serve all information to web interface
 Static Content Serving
 Express and Socket.io modules of Node.js
 Handles user inputs from web interface
 Management of all cameras
 Handling multi-client/multi-camera systems
34
Server App
35
Server App
36
Server App
37
Server App
38
Server App
39
Application - Web Interface
 Web Interface
 HTML5/Javascript
 Web Sockets
 Socket.io
 Angular.js
 Ajax Based
 No need to refresh
 Browser Compatibility
 IE9, Firefox, Chrome tested
40
Web Interface
WebSocket Code Samples
 From “http://socket.io/#how-to-use”
41
Web Interface
42
Web Interface
43
Outline
 Demo
 Questions
44
Questions
 Demo Codes
 github.com/mfkaragoz/elce2013demo
 Thank You!
 Mehmet Fatih KARAGOZ

mfatihkaragoz@yahoo.com
 Cevahir TURGUT
cevahir.turgut@gmail.com
45

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Node.

 Open source  Small Developer Pool

 Node.JS uses Javascript

 Most web developers are familiar with the language

 NodeJS package management system

 Node.js is released under the MIT license.

 ./configure --without-snapshot --dest-cpu=arm --dest-os=linux

 setBreakpoint(), sb() - Set breakpoint on current line

 backtrace, bt - Print backtrace of current execution frame

var exec = require(‘child_process’).exec;

“npm install iniparser”

 Example Surveillance System

 Mehmet Fatih KARAGOZ

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