Nodejs - A quick tour (v4)
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- Node.js is a platform for building scalable network applications. It uses non-blocking I/O and event-driven architecture to handle many connections concurrently using a single-threaded event loop. - Node.js uses Google's V8 JavaScript engine and provides a module system, I/O bindings, and common protocols to build network programs easily. Popular uses include real-time web applications, file uploading, and streaming. - While Node.js is ready for many production uses, things like lost stack traces and limited ability to utilize multiple cores present challenges for some workloads. However, an active community provides support through mailing lists, IRC, and over 1,000 modules in its package manager.
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Nodejs - A quick tour (v4)
- 1. node.js A quick tour 15.02.2011 (v4)
- 2. About • Felix Geisendörfer • 23 years • Berlin, Germany @felixge
- 3. Core Contributor & Module Author node-mysql node-formidable
- 4. File uploading & processing as an infrastructure service for web & mobile applications.
- 5. Audience?
- 6. Node's goal is to provide an easy way to build scalable network programs.
- 7. Node.js • Created by Ryan Dahl • Google’s V8 JavaScript engine (no DOM) • Module system, I/O bindings, Common Protocols
- 8. Installing $ git clone git://github.com/ry/node.git $ cd node $ ./configure $ make install
- 9. Hello World $ cat test.js console.log('Hello World'); $ node test.js Hello World
- 10. Ingredients libeio libev c-ares V8 http_parser
- 11. Philosophy • Just enough core-library to do I/O • Non-blocking • Close to the underlaying system calls
- 12. Non-blocking I/O
- 13. Blocking I/O var a = db.query('SELECT A'); console.log('result a:', a); var b = db.query('SELECT B'); console.log('result b:', b); Time = SUM(A, B)
- 14. Non-Blocking I/O db.query('SELECT A', function(result) { console.log('result a:', result); }); db.query('SELECT B', function(result) { console.log('result b:', result); }); Time = MAX(A, B)
- 15. Non-Blocking I/O • Offload most things to the kernel and poll for changes (select, epoll, kqueue, etc.) • Thread pool for anything else
- 16. Single Threaded var a = []; function f() { a.push(1); a.push(2); } setTimeout(f, 10); setTimeout(f, 10);
- 17. Single Threaded var a = []; function f() { • [1, 1, 2, 2] ? a.push(1); a.push(2); } • [1, 2, 1, 2] ? setTimeout(f, 10); • BAD ACCESS ? setTimeout(f, 10);
- 18. Single Threaded var a = []; function f() { • [1, 1, 2, 2] a.push(1); a.push(2); } • [1, 2, 1, 2] setTimeout(f, 10); • BAD ACCESS setTimeout(f, 10);
- 19. API Overview
- 20. CommonJS Modules $ cat hello.js exports.world = function() { return 'Hello World'; }; $ cat main.js var hello = require('./hello'); console.log(hello.world()); $ node main.js Hello World
- 21. Child processes $ cat child.js var spawn = require('child_process').spawn; var cmd = 'echo hello; sleep 1; echo world;'; var child = spawn('sh', ['-c', cmd]); child.stdout.on('data', function(chunk) { console.log(chunk.toString()); }); $ node child.js "hellon" # 1 sec delay "worldnn"
- 22. Http Server $ cat http.js var http = require('http'); http.createServer(function(req, res) { setTimeout(function() { res.writeHead(200); res.end('Thanks for waiting!'); }, 1000); }).listen(4000); $ curl localhost:4000 # 1 sec delay Thanks for waiting!
- 23. Tcp Server $ cat tcp.js var tcp = require('tcp'); tcp.createServer(function(socket) { socket .on('connect', function() { socket.write("Hi, How Are You?n> "); }) .on('data', function(data) { socket.write(data); }); }).listen(4000); $ nc localhost 4000 Hi, How Are You? > Great! Great!
- 24. DNS $ cat dns.js var dns = require('dns'); dns.resolve('nodejs.org', function(err, addresses) { console.log(addresses); }); $ node dns.js [ '8.12.44.238' ]
- 25. Watch File $ cat watch.js var fs = require('fs'); fs.watchFile(__filename, function() { console.log('You changed me!'); process.exit(0); }); $ node watch.js # edit watch.js You changed me!
- 26. And much more • UDP • Buffer • Crypto • Script • Assert • EcmaScript5 ...
- 28. Suitable Applications • Singe-page apps • Real time • Crawlers
- 29. More Applications • Async chaining of unix tools • Streaming • File uploading
- 32. Web Frameworks • Express.js (Sinatra clone) • Fab.js (Mind-bending & awesome)
- 33. DOM • node-htmlparser • jquery • node.io
- 35. 1171 modules in npm
- 37. Ready for production? • 0.4 was released last week • API has settled down for most parts • Very few bugs, but YMMV
- 38. Things that suck
- 39. Things that suck • Stack traces are lost at the event loop boundary • Utilizing multiple cores requires multiple processes • V8: 1.9 GB heap limit / GC can be problematic
- 40. Community
- 41. Benevolent Dictator For Life Ryan Dahl
- 42. Community • Mailing list (nodejs, nodejs-dev) • IRC (#node.js)
- 43. Hosting
- 44. Questions? ✎ @felixge / felix@debuggable.com
- 45. Bonus Slides
- 46. Speed
- 47. Speed var http = require(’http’) var b = new Buffer(1024*1024); http.createServer(function (req, res) { res.writeHead(200); res.end(b); }).listen(8000); by Ryan Dahl
- 48. Speed 100 concurrent clients 1 megabyte response node 822 req/sec nginx 708 thin 85 mongrel 4 (bigger is better) by Ryan Dahl
- 49. Speed • NGINX peaked at 4mb of memory • Node peaked at 60mb • Very special circumstances by Ryan Dahl
- 50. Questions? ✎ @felixge / felix@debuggable.com