Tom Hughes-Croucher - Up and Running with Node.js

Transcript

1. A language for the Internet Why JavaScript and Node.js is

   right for Internet Applications Tom Hughes-Croucher @sh1mmer

2. Me (@sh1mmer)

3. None

4. Scalable Server-Side Code with JavaScript Tom Hughes-Croucher Node Up and

   Running

5. Internet?

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8. She’s called Eleanor

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14. More features More users More devices More data

15. Stuff Cost

16. How do we cope with the increase in demand?

17. Internet Applications

18. How about search?

19. Browser Spidering Server Web Sites

20. Would take forever!

21. Browser Front-end Server Database Computation

22. Client → Server Computation Batch Computing

23. None

24. Client → Server Server → DB Computation Computation Internet Computing

25. “Traditional” Approach

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27. Server

28. Request

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31. FULL

32. Event-driven Approach

33. Request Place- holder

34. None

35. Shared Work Resources

36. Welcome to Node.js

37. Node.js? • Server Side JavaScript runtime • Built on top

    of V8 JavaScript engine from Google Chrome • Non-blocking I/O APIs • Easy to extend APIs and modules

38. $Enki:~ $ node

39. $Enki:~ $ node > 3 > 2 > 1 false

    > true == 1 true > true === 1 false

40. > console.log('Hello World'); Hello World > .help .clear Break, and

    also clear the local context. .exit Exit the prompt .help Show repl options > .clear Clearing context... > .exit Enki:~ $

41. Enki:~ $ node > var foo = "bar"; > foo;

    'bar' > .clear Clearing context... > foo ReferenceError: foo is not defined at [object Context]:1:1 at Interface.<anonymous> (repl:98:19) at Interface.emit (events:27:15) at Interface._ttyWrite (readline:295:12) at Interface.write (readline:132:30) at Stream.<anonymous> (repl:79:9) at Stream.emit (events:27:15) at IOWatcher.callback (net:489:16)

42. var http = require('http'); http.createServer(function (req, res) { res.writeHead(200, {'Content-Type':

    'text/plain'}); res.end('Hello World\n'); }).listen(8124, "127.0.0.1"); console.log('Server running at http://127.0.0.1:8124/');

43. var http = require('http'); //include the http library

44. http.createServer(function (req, res) { }).listen(8124, "127.0.0.1"); //create an http server

    //when ‘stuff’ happens call this anonymous function //listen on port 8124 of the IP 127.0.0.1

45. http.createServer(function (req, res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello World\n'); })

    //when ‘stuff’ happens my function fires //I get a request object and a response object //I write to the response object header //HTTP status 200 and content-type ‘text/plain’ //close the response with the body: //Hello World

46. console.log('Server running at http://127.0.0.1:8124/'); //write Server is running at http://127.0.0.1:8124/

    //to the console

47. Why is Node.js suited to Internet Apps?

48. None

49. What is the event loop?

50. None

51. Multi-tasking, one thing at a time.

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54. var http = require('http'); server = http.createServer(); server.on('request', function (req,

    res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello World\n'); }); server.listen(8124, "127.0.0.1"); console.log('Server running at http://127.0.0.1:8124/');

55. var http = require('http'); server = http.createServer(); server.on('request', function (req,

    res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello World\n'); }); server.listen(8124, "127.0.0.1"); console.log('Server running at http://127.0.0.1:8124/'); Step 1. Evaluate 'Main'

56. var http = require('http'); server = http.createServer(); server.on('request', function (req,

    res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello World\n'); }); server.listen(8124, "127.0.0.1"); console.log('Server running at http://127.0.0.1:8124/'); Step 1. variables: http -> http module server -> http server listeners: server.request -> function

57. var http = require('http'); server = http.createServer(); server.on('request', function (req,

    res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello World\n'); }); server.listen(8124, "127.0.0.1"); console.log('Server running at http://127.0.0.1:8124/'); Step 2. Event Loop *

58. var http = require('http'); server = http.createServer(); server.on('request', function (req,

    res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello World\n'); }); server.listen(8124, "127.0.0.1"); console.log('Server running at http://127.0.0.1:8124/'); Step 2. Do we have active listeners? listeners: server.request -> function Yes! Wait for listeners. *

59. var http = require('http'); server = http.createServer(); server.on('request', function (req,

    res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello World\n'); }); server.listen(8124, "127.0.0.1"); console.log('Server running at http://127.0.0.1:8124/'); Step 3. Event Calls

60. var http = require('http'); server = http.createServer(); server.on('request', function (req,

    res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello World\n'); }); server.listen(8124, "127.0.0.1"); console.log('Server running at http://127.0.0.1:8124/'); Step 3. 'request' is called. Since listeners: server.request -> function Call function

61. var http = require('http'); server = http.createServer(); server.on('request', function (req,

    res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello World\n'); }); server.listen(8124, "127.0.0.1"); console.log('Server running at http://127.0.0.1:8124/'); Step 3. Loop! (go to Step 2.)

62. Why non-blocking matters

63. Event Loop vs. Threads

64. //node.js style JavaScript query = mysql.query('SELECT * FROM data'); query.on(‘result’,

    function(result) { for(var i=0;i<length;i++) { var row = result.rows[i]; //do something with the row } });

65. //threaded style JavaScript result = mysql.query('SELECT * FROM data'); for(var

    i=0;i<length;i++) { var row = result.rows[i]; //do something with the row }

66. var x = "I am a string" ~1ns Running 1

    instruction 2ns Data from l1 cpu cache 5ns Data from l2 cpu cache 80ns Data from ram

67. Server mySQL query result

68. result = mysql.query('SELECT * FROM data'); ~100ms Time to run

    a query in database 50ms Time to roundtrip query over the network

69. Local variable

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71. Remote operation

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73. Cat 100 Blue Whales

74. Blocking is as bad as stopping

75. Threading wastes memory for a long time because of programming

    style

76. 2mb PHP 8gb ram 8000/2 = 4000 ~4000 users per

    machine

77. 8gb ram 8000/0.006 = 1.3m 1.3m/2 ~ 650k users Node.js

    TCP = 2kb HTTP = 6kb

78. Apache vs NGINX concurrency × reqs/sec http://blog.webfaction.com/a-little-holiday-present

79. Apache vs NGINX concurrency × memory http://blog.webfaction.com/a-little-holiday-present

80. Node.js is designed for communication, just like your applications

81. Demo

82. Thanks!

83. Follow me @sh1mmer Tom Hughes-Croucher @sh1mmer