Nodejs Event Driven Concurrency for Web Applications
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The document discusses Node.js as a server-side JavaScript runtime built on Google’s V8 engine, emphasizing its event-driven, non-blocking I/O model that enhances scalability for web applications. It contrasts thread-based approaches with event-based models, highlighting Node.js's efficient handling of multiple connections through a single thread, thereby reducing overhead. Additionally, it covers Node.js architecture, its ecosystem, middleware options like Connect.js and Express.js, and strategies for scaling across multi-core servers.
Nodejs Event Driven Concurrency for Web Applications
- 1. Nodejs Event-Driven concurrency for Web Applications Ganesh Iyer @lastlegion http://ganeshiyer.net
- 2. What is Node Server-side JavaScript runtime http://ganeshiyer.net
- 3. What is Node Server-side JavaScript runtime http://ganeshiyer.net
- 4. What is Node Server-side JavaScript runtime Built on Google’s V8 Engine http://ganeshiyer.net
- 5. What is Node Server-side JavaScript runtime Built on Google’s V8 Engine http://ganeshiyer.net
- 6. What is Node Server-side JavaScript runtime Built on Google’s V8 Engine Why another server side technology? http://ganeshiyer.net
- 7. What is Node Server-side JavaScript runtime Built on Google’s V8 Engine Why another server side technology? http://ganeshiyer.net
- 8. What is Node Server-side JavaScript runtime Built on Google’s V8 Engine Why another server side technology? http://ganeshiyer.net
- 9. What is Node Server-side JavaScript runtime Built on Google’s V8 Engine Why another server side technology? http://ganeshiyer.net
- 10. What is Node Server-side JavaScript runtime Built on Google’s V8 Engine Uses an event-driven, non-blocking I/O model for building scalable network applications http://ganeshiyer.net
- 11. What is Node Server-side JavaScript runtime Built on Google’s V8 Engine Uses an event-driven, non-blocking I/O model for building scalable network applications http://ganeshiyer.net
- 12. What is Node Server-side JavaScript runtime Built on Google’s V8 Engine Uses an event-driven, non-blocking I/O model for building scalable network applications http://ganeshiyer.net
- 13. What is Node Server-side JavaScript runtime Built on Google’s V8 Engine Uses an event-driven, non-blocking I/O model for building scalable network applications http://ganeshiyer.net
- 14. Concurrency in web servers http://ganeshiyer.net
- 15. Two main approaches • Threads • Events http://ganeshiyer.net
- 16. Thread Based • Creates a new thread( or process) for handling a new connection. http://ganeshiyer.net
- 17. Thread Based • Creates a new thread( or process) for handling a new connection. Server Process http://ganeshiyer.net
- 18. Thread Based • Creates a new thread( or process) for handling a new connection. New Connection Server Process http://ganeshiyer.net
- 19. Thread Based • Creates a new thread( or process) for handling a new connection. Request handler Process New Connection Server Process http://ganeshiyer.net
- 20. Thread Based • Creates a new thread( or process) for handling a new connection. Request handler Process Server Process http://ganeshiyer.net
- 21. Thread Based • Creates a new thread( or process) for handling a new connection. Request handler Process Server Process http://ganeshiyer.net
- 22. Threads used in Apache(MPM) Prefork http://ganeshiyer.net
- 23. Threads used in Apache(MPM) Worker http://ganeshiyer.net
- 24. Scalability Issues There is a maximum number of threads(T’) that a system can support, beyond which the throughput decreases. http://ganeshiyer.net
- 25. Scalability Issues Source: M. Welsh, S. D. Gribble, E. A. Brewer, and D. Culler. A design framework for highly con-current systems. Technical Report UCB/CSD-00-1108, U.C. Berkeley Computer Science Division, April 2000. http://ganeshiyer.net
- 26. Scalability Issues Under heavy load a multi-threaded web server consumers large amounts of memory http://ganeshiyer.net
- 27. Scalability Issues Under heavy load a multi-threaded web server consumers large amounts of memory Single thread stack for each connection http://ganeshiyer.net
- 28. Scalability Issues Under heavy load a multi-threaded web server consumers large amounts of memory Single thread stack for each connection Overhead due to context-switching and scheduling increases drastically with large number of threads http://ganeshiyer.net
- 29. Event Based http://ganeshiyer.net
- 30. Event Based States Event Event Handler Loop Event Queue http://ganeshiyer.net
- 31. Event Based Event Emitters States Event Event Handler Loop Event Queue http://ganeshiyer.net
- 32. Event Based Event Emitters States Event Event Handler Loop Event Queue http://ganeshiyer.net
- 33. Event Based Use an event loop http://ganeshiyer.net
- 34. Event Based Use an event loop Multiple connections are mapped to a single thread. http://ganeshiyer.net
- 35. Event Based Use an event loop Multiple connections are mapped to a single thread. This Thread handles all occurring events from I/O operations of these connections and requests. http://ganeshiyer.net
- 36. Improved scalability Source: M. Welsh, S. D. Gribble, E. A. Brewer, and D. Culler. A design framework for highly con-current systems. Technical Report UCB/CSD-00-1108, U.C. Berkeley Computer Science Division, April 2000. http://ganeshiyer.net
- 37. Improved scalability The event loop has a queue of event handlers that it executes in order. The overhead when switching from one event handler to the next time is much lower. http://ganeshiyer.net
- 39. Why Server-side JavaScript? Unified language for both front end an backend http://ganeshiyer.net
- 40. Why Server-side JavaScript? Unified language for both front end an backend Increased programmer productivity http://ganeshiyer.net
- 41. Why Server-side JavaScript? Unified language for both front end an backend Increased programmer productivity Code reuse http://ganeshiyer.net
- 42. Why Server-side JavaScript? Unified language for both front end an backend Increased programmer productivity Code reuse exchange of data using JSON http://ganeshiyer.net
- 43. Why Server-side JavaScript? Unified language for both front end an backend Increased programmer productivity Code reuse exchange of data using JSON Speed! http://ganeshiyer.net
- 44. Why Server-side JavaScript? Unified language for both front end an backend Increased programmer productivity Code reuse exchange of data using JSON Speed! Contrary to popular belief, Javascript with the V8 engine performs is faster than PHP, Ruby and Python http://ganeshiyer.net
- 45. Nodejs Architecture http://ganeshiyer.net
- 46. Architecture JavaScript C++ http://ganeshiyer.net
- 47. Architecture JavaScript C++ JavaScript Engine http://ganeshiyer.net
- 48. Architecture JavaScript C++ Event-based fully asynchronous I/O library. http://ganeshiyer.net
- 49. Architecture JavaScript C++ The event loop http://ganeshiyer.net
- 50. Architecture JavaScript C++ Exposes OS features like file handling, sockets etc. Functionality for HTTP, DNS etc http://ganeshiyer.net
- 51. The EventDriven model http://ganeshiyer.net
- 53. Nodejs: Hello World http://ganeshiyer.net
- 54. Nodejs: Hello World Output $ Hello World http://ganeshiyer.net
- 55. Hello World revisited VS Synchronous Asynchronous http://ganeshiyer.net
- 56. Hello World revisited VS Output $ hello http://ganeshiyer.net
- 57. Hello World revisited VS Output $ hello 2 seconds later http://ganeshiyer.net
- 58. Hello World revisited VS Output $ hello 2 seconds later $ world http://ganeshiyer.net
- 59. Hello World revisited VS Output New request to Node $ hello During those two seconds http://ganeshiyer.net
- 60. Hello World revisited VS Output New requests to Node $ hello During those two seconds http://ganeshiyer.net
- 61. Hello World revisited VS Since it is non-blocking Output $ hello 2 seconds later $ hello 2 seconds later $ hello 2 seconds later $ world $ world $ world Response Response Response http://ganeshiyer.net
- 62. Creating an HTTP server http://ganeshiyer.net
- 63. Creating an HTTP server Require http module http://ganeshiyer.net
- 64. Creating an HTTP server Callback executed on each request http://ganeshiyer.net
- 65. Static file serving web server http://ganeshiyer.net
- 66. Static file serving web server Parsing the url for pathname http://ganeshiyer.net
- 67. Node provides low-level functionality For buliding web-applications we require higher functionality Node has a lot of packages that help! http://ganeshiyer.net
- 68. Node Ecosystem http://ganeshiyer.net
- 69. Package management with npm Predominant package manager for node To install ‘express’ package http://ganeshiyer.net
- 70. Connect.js : Middleware for nodejs Essential middleware required for developing web applications Implements logging, caching, cookies, sessions etc. http://ganeshiyer.net
- 71. Connect.js : Middleware for nodejs Essential middleware required for developing web applications • logger request logger with custom format support • csrf Cross-site request forgery protection • basicAuth basic http authentication • bodyParser extensible request body parser • json application/json parser • urlencoded application/x-www-form-urlencoded parser • cookieParser cookie parser • session session management support with bundled MemoryStore • cookieSession cookie-based session support • staticCache memory cache layer for the static() middleware http://ganeshiyer.net
- 72. Connect.js : Middleware for nodejs http://ganeshiyer.net
- 73. Express.js : A MVC framework for web Applications http://ganeshiyer.net
- 74. Express.js : A MVC framework for web Applications Model View Controller http://ganeshiyer.net
- 75. Express.js : A MVC framework for web Applications Model View Controller Performs RESTful routing http://ganeshiyer.net
- 76. Express.js : A MVC framework for web Applications Model View Controller Performs RESTful routing Uses Templating for rendering html http://ganeshiyer.net
- 77. Scalability across multiple cores/servers http://ganeshiyer.net
- 78. Scalability across multiple cores/servers Node is single threaded! http://ganeshiyer.net
- 79. Scalability across multiple cores/servers Node is single threaded! How is going to scale on my multi-core server!? http://ganeshiyer.net
- 80. Scalability across multiple cores/servers Start child processes on multiple cores/servers. One process manages flow of events and other cores for doing computation. http://ganeshiyer.net
- 81. Scalability across multiple cores/servers Cluster is an extensible multi-core server manager for node.js. http://ganeshiyer.net