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Node.js Explained

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Jeff Kunkle

Rising from non-existence a few short years ago, Node.js is already attracting the accolades and disdain enjoyed and endured by the Ruby and Rails community just a short time ago. It overtook Rails as the most popular Github repository in 2011 and was selected by InfoWorld for the Technology of the Year Award in 2012. This presentation explains the basic theory and programming model central to Node's approach and will help you understand the resulting benefits and challenges it presents. You can also watch this presentation at http://bit.ly/1362UGA

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explained March 2, 2012 Jeff Kunkle
Node.js is a platform built on Chrome’s JavaScript runtime for easily building fast, scalable network applications. Node.js uses an event driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices. DOWNLOAD DOCS v0.6.11
1 Theory 2 Challenges 3 Benefits
Theory
I/O Latency L1 3 cycles L2 14 cycles RAM 250 cycles Disk 41,000,000 Network 240,000,000 Source: Ryan Dahl’s 2008.11.08 node.js presentation
CPU Cycles 300,000,000 240,000,000 225,000,000 150,000,000 75,000,000 41,000,000 3 14 250 0 L1 L2 RAM Disk Network
I/O Latency L2 RAM Disk Network L1 5 83 13,666,666 80,000,000 L2 18 2,928,571 17,142,857 RAM 164,000 960,000 Disk 6
Waiting... route process format request results response query db or write to web service log file
Scaling with Threads Handles up to 4 concurrent requests thread 1 thread 2 thread 3 thread 4 Context switching overhead Execution stacks take up memory Complicates concurrency
Scaling with Processes Handles up to 4 concurrent requests process 1 process 2 process 3 process 4 High memory usage Process scheduling overhead
Scaling with an Event Loop Handles many concurrent requests in one process/thread process 1 network filesystem Thread Pool and Async I/O APIs
Event Loop Thread Pool Event filesystem Queue network Event Loop process other
Platform node standard library node bindings (http, socket, file system) thread pool event loop crypto DNS V8 (libeio) (libev) (OpenSSL) (c-ares)
Examples setTimeout(function () { console.log('This will still run.'); }, 500);
HTTP Server var http = require('http'); http.createServer(function (request, response) { response.writeHead(200, {'Content-Type': 'text/plain'}); response.end('Hello Worldn'); }).listen(8124); console.log('Server running at http://127.0.0.1:8124/');
Serve a Static File var http = require('http'); http.createServer(function (request, response) { fs.readFile('/etc/passwd', function (err, data) { if (err) { response.writeHead(500, err.message); response.end(); } else { response.writeHead(200, {'Content-Type': 'text/plain'}); response.end(data); } }); }).listen(8124);
Read a File in Chunks var fs = require('fs'); var stream = fs.createReadStream('huge.txt'); stream.on('data', function (data) { console.log(data); }); stream.on('end', function () { console.log('done'); }); stream.on('error', function (err) { console.log(err); });
Challenges
Asynchronous I/O var fs = require('fs'); fs.stat('/etc/passwd', function (err, stats) { if (err) return; if (stats.isFile()) { fs.readFile('/etc/passwd', function (err, data) { if (err) throw err; console.log(data); }); } });
Debugging
CPU-intensive Tasks 1 thread be careful!
Rapidly Changing v0.6.12 2012.03.02 v0.7.5 2012.02.23 v0.6.11 2012.02.17 v0.7.4 2012.02.14 v0.6.10 2012.02.02 v0.7.3 2012.02.07 v0.6.9 2012.01.27 v0.7.2 2012.02.01 v0.6.8 2012.01.19 v0.7.1 2012.01.23 v0.6.7 2012.01.06 v0.7.0 2012.01.16
Benefits
Multi-platform
Lightweight Single thread
Dead-lock Free Single thread simplifies concurrency
Monoglot Programming JavaScript on the client JavaScript on the server
Popular
Fast Ruby 1.9 used what fraction? times more? Benchmark Time Memory Code pidigits 1 /16 1/ 2 1/ 3 reverse-complement 1/ 2 1/ 2 1/ 2 k-nucleotide 2× 1/ 2 ± binary-trees 6× 1/ 2 ± fasta 7× 6× ± regex-dna 9× 2× ± n-body 16× 1/ 4 ± spectral-norm 19× 1/ 2 ± fannkuch-redux 51× ± ± Source: http://shootout.alioth.debian.org/u32/benchmark.php
Lua
Perl
PHP
Python 3
JRuby
Clojure
Java
C
Vibrant Community 7,661 packages as of 3:00pm EDT 2012.03.02
Conceptually Simple Thread Pool Event filesystem Queue network Event Loop process other
Small Core 36 JavaScript source files 36 C++ source files as of March 1, 2012 at 10:50pm on v0.6 branch
Short Learning Curve Understand Node.js Theory Understand JavaScript Understand Event-based Programming You just need to learn new APIs
Getting Smart
1 install Node from source 2 write some small programs 3 read the source 4 re-implement a popular pkg
Check out some Packages express web framework async helpers async persist socket.io realtime networking ORM framework db-migrate vowsframework BDD database migrations dnode RPC java to Java API bridge

More Related Content

Node.js Explained

  • 1. explained March 2, 2012 Jeff Kunkle
  • 2. Node.js is a platform built on Chrome’s JavaScript runtime for easily building fast, scalable network applications. Node.js uses an event driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices. DOWNLOAD DOCS v0.6.11
  • 3. 1 Theory 2 Challenges 3 Benefits
  • 5. I/O Latency L1 3 cycles L2 14 cycles RAM 250 cycles Disk 41,000,000 Network 240,000,000 Source: Ryan Dahl’s 2008.11.08 node.js presentation
  • 6. CPU Cycles 300,000,000 240,000,000 225,000,000 150,000,000 75,000,000 41,000,000 3 14 250 0 L1 L2 RAM Disk Network
  • 7. I/O Latency L2 RAM Disk Network L1 5 83 13,666,666 80,000,000 L2 18 2,928,571 17,142,857 RAM 164,000 960,000 Disk 6
  • 8. Waiting... route process format request results response query db or write to web service log file
  • 9. Scaling with Threads Handles up to 4 concurrent requests thread 1 thread 2 thread 3 thread 4 Context switching overhead Execution stacks take up memory Complicates concurrency
  • 10. Scaling with Processes Handles up to 4 concurrent requests process 1 process 2 process 3 process 4 High memory usage Process scheduling overhead
  • 11. Scaling with an Event Loop Handles many concurrent requests in one process/thread process 1 network filesystem Thread Pool and Async I/O APIs
  • 12. Event Loop Thread Pool Event filesystem Queue network Event Loop process other
  • 13. Platform node standard library node bindings (http, socket, file system) thread pool event loop crypto DNS V8 (libeio) (libev) (OpenSSL) (c-ares)
  • 14. Examples setTimeout(function () { console.log('This will still run.'); }, 500);
  • 15. HTTP Server var http = require('http'); http.createServer(function (request, response) { response.writeHead(200, {'Content-Type': 'text/plain'}); response.end('Hello Worldn'); }).listen(8124); console.log('Server running at http://127.0.0.1:8124/');
  • 16. Serve a Static File var http = require('http'); http.createServer(function (request, response) { fs.readFile('/etc/passwd', function (err, data) { if (err) { response.writeHead(500, err.message); response.end(); } else { response.writeHead(200, {'Content-Type': 'text/plain'}); response.end(data); } }); }).listen(8124);
  • 17. Read a File in Chunks var fs = require('fs'); var stream = fs.createReadStream('huge.txt'); stream.on('data', function (data) { console.log(data); }); stream.on('end', function () { console.log('done'); }); stream.on('error', function (err) { console.log(err); });
  • 19. Asynchronous I/O var fs = require('fs'); fs.stat('/etc/passwd', function (err, stats) { if (err) return; if (stats.isFile()) { fs.readFile('/etc/passwd', function (err, data) { if (err) throw err; console.log(data); }); } });
  • 21. CPU-intensive Tasks 1 thread be careful!
  • 22. Rapidly Changing v0.6.12 2012.03.02 v0.7.5 2012.02.23 v0.6.11 2012.02.17 v0.7.4 2012.02.14 v0.6.10 2012.02.02 v0.7.3 2012.02.07 v0.6.9 2012.01.27 v0.7.2 2012.02.01 v0.6.8 2012.01.19 v0.7.1 2012.01.23 v0.6.7 2012.01.06 v0.7.0 2012.01.16
  • 25. Lightweight Single thread
  • 26. Dead-lock Free Single thread simplifies concurrency
  • 27. Monoglot Programming JavaScript on the client JavaScript on the server
  • 29. Fast Ruby 1.9 used what fraction? times more? Benchmark Time Memory Code pidigits 1 /16 1/ 2 1/ 3 reverse-complement 1/ 2 1/ 2 1/ 2 k-nucleotide 2× 1/ 2 ± binary-trees 6× 1/ 2 ± fasta 7× 6× ± regex-dna 9× 2× ± n-body 16× 1/ 4 ± spectral-norm 19× 1/ 2 ± fannkuch-redux 51× ± ± Source: http://shootout.alioth.debian.org/u32/benchmark.php
  • 30. Lua
  • 31. Perl
  • 32. PHP
  • 34. JRuby
  • 36. Java
  • 37. C
  • 38. Vibrant Community 7,661 packages as of 3:00pm EDT 2012.03.02
  • 39. Conceptually Simple Thread Pool Event filesystem Queue network Event Loop process other
  • 40. Small Core 36 JavaScript source files 36 C++ source files as of March 1, 2012 at 10:50pm on v0.6 branch
  • 41. Short Learning Curve Understand Node.js Theory Understand JavaScript Understand Event-based Programming You just need to learn new APIs
  • 43. 1 install Node from source 2 write some small programs 3 read the source 4 re-implement a popular pkg
  • 44. Check out some Packages express web framework async helpers async persist socket.io realtime networking ORM framework db-migrate vowsframework BDD database migrations dnode RPC java to Java API bridge