Node.js cluster
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The document discusses the use of Node.js clusters for managing multiple processes to enhance performance in applications. It explains how the cluster module works, including the role of the master process and worker processes in handling TCP connections, as well as its application in a Telegram bot game. It also notes the challenges of using clusters, such as high memory usage and the cost of context switching, advising careful use of the clustering approach.
Node.js cluster
- 1. Globalcode â Open4education Node.js Cluster Derek Stavis Software Engineer
- 2. Globalcode â Open4education Who? Derek Stavis github.com/derekstavis Software Engineer @ Pagar.me Ruby, JavaScript, Python, Go, C Node, React & Webpack Advocate
- 3. Globalcode â Open4education Node.js Runtime
- 4. Globalcode â Open4education single threaded non-blocking asynchronous concurrent engine
- 5. Globalcode â Open4education Heap Memory Available Task Queue listOnTimeout listOnTimeout listOnTimeout listOnTimeout listOnTimeout Delayed Tasks Call Stack write() saveFile() updateTime() tryOnTimeout listOnTimeout Execution Contexts Vendor APIs (Node, Web) Runtime and Platform Abstraction Event Loop Task Scheduler
- 6. Globalcode â Open4education Single threaded
- 7. Globalcode â Open4education Isnât concurrent sufficient?
- 8. Globalcode â Open4education We have multiple processors for a while
- 9. Globalcode â Open4education We want to distribute the load
- 10. Globalcode â Open4education Enter cluster module
- 11. Globalcode â Open4education const cluster = require('cluster'); const http = require('http'); const numCPUs = require('os').cpus().length How to
- 12. Globalcode â Open4education if (cluster.isMaster) { console.log(`Master ${process.pid} is running`); // Fork workers. for (let i = 0; i < numCPUs; i++) { cluster.fork(); } cluster.on('exit', (worker, code, signal) => { console.log(`worker ${worker.process.pid} died`); }); } How to
- 13. Globalcode â Open4education else { // Workers can share any TCP connection // In this case it is an HTTP server http.createServer((req, res) => { res.writeHead(200); res.end('hello worldn'); }).listen(8000); console.log(`Worker ${process.pid} started`); } How to
- 16. Globalcode â Open4education Two processes binding on the same port?
- 17. Globalcode â Open4education cluster is just a wrapper for child_process.fork
- 18. Globalcode â Open4education Socket.listen is aware of cluster module
- 19. Globalcode â Open4education When a âslaveâ process uses a Socket
- 20. Globalcode â Open4education The underlying implementation listens on a file descriptor
- 21. Globalcode â Open4education That is fed by the master process
- 22. Globalcode â Open4education Master process acts like a load balancer
- 24. Globalcode â Open4education Perk: You can do clustering with anything that is socket based
- 25. Globalcode â Open4education Here comes the JabĂĄ
- 26. Globalcode â Open4education TeleMMO is a RPG game into a Telegram bot
- 27. Globalcode â Open4education We needed to make our game multicore
- 28. Globalcode â Open4education Telegram API can use two modes: Polling and Webhook
- 29. Globalcode â Open4education Webhooks are based on a HTTP server
- 30. Globalcode â Open4education We use a third-party module to integrate with Telegram
- 31. Globalcode â Open4education Cluster came in handy
- 32. Globalcode â Open4education We just followed the standard path (click me)
- 34. Globalcode â Open4education What more?
- 35. Globalcode â Open4education You can do nice things
- 36. Globalcode â Open4education Zero downtime code reload
- 37. Globalcode â Open4education Process management
- 38. Globalcode â Open4education Automatic software update
- 39. Globalcode â Open4education var recluster = require('recluster'), path = require('path'); var cluster = recluster(path.join(__dirname, 'server.js')); cluster.run(); process.on('SIGUSR2', function() { console.log('Got SIGUSR2, reloading cluster...'); cluster.reload(); }); console.log("spawned cluster, kill -s SIGUSR2", process.pid, "to reload"); https://github.com/doxout/recluster
- 40. Globalcode â Open4education Is it all flowers?
- 42. Globalcode â Open4education Processes are heavy
- 43. Globalcode â Open4education They are subject to operating system scheduling
- 44. Globalcode â Open4education Context switches are very expensive
- 45. Globalcode â Open4education Memory usage is high
- 46. Globalcode â Open4education Each worker reloads the entire application into memory
- 47. Globalcode â Open4education Kinda hacky, huh?
- 48. Globalcode â Open4education So, use it wisely
- 49. Globalcode â Open4education Donât do more processes than the number of CPUs
- 50. Globalcode â Open4education Donât use it to fix your bad code performance
- 52. Globalcode â Open4education Thanks for watching Questions? github.com/derekstavis twitter.com/derekstavis facebook.com/derekstavis