Node.js production checklist

At RisingStack, we have helped enterprises to successfully adopt Node.js in the past years. During this period, we have seen a lot of anti-patterns and war stories. Also, we came up with a list of best practices on how to run Node.js applications in production successfully.

This talk addresses both operational, performance and security best practices.

Transcript

1. Node.js Production Checklist Gergely Nemeth @nthgergo | nemethgergely.com
2. Hi, I am Gergely. ▪ Works at GoDaddy ▪ Previously RisingStack ▪ To chat with me: – @nthgergo – mail@nemethgergely.com ▪ Read my stuff: – nemethgergely.com
3. Node.js Production Checklist Gergely Nemeth @nthgergo | nemethgergely.com
4. Why do you need a production checklist?
5. Why do you need a production checklist? ▪ Providing a “three nines” (99,9%) service, this is your error budget: – 43 minutes of downtime in a month – 2.2 hours of downtime in a quarter – 8.8 hours of downtime in a year
6. Why do you need a production checklist? ▪ Providing a “five nines” (99,999%) service – 26 seconds of downtime in a month – 78 seconds of downtime in a quarter – 5 minutes of downtime in a year
7. Why do you need a production checklist? ▪ These are called SLAs (service level agreement) ▪ SLAs consist of an SLO (service level objectives) and penalties if you don’t meet them, like the 99% of the requests finish under 200 ms
8. Why do you need a production checklist? If you are operating a service, you should define SLOs for your customers – no matter if they are internal or external
9. Today, you will learn about: ▪ Error handling in Node.js ▪ How to secure your Node.js applications ▪ Building a CI/CD pipeline for Node.js ▪ How to get full visibility into production systems – Best practices for logging – Monitoring your Node.js applications ▪ What to do after hell broke loose
10. Error handling
11. Error handling
12. Error handling Async-await changes how we write Node.js applications
13. Error handling You have to learn to throw again
14. Error handling - Express app.get('/users/:id', (req, res) => { const userId = req.params.id if (!userId) { return res.sendStatus(400).json({ error: 'Missing id' }) } Users.get(userId, (err, user) => { if (err) { return res.sendStatus(500).json(err) } res.send(users) }) })
15. Error handling - Express - Errors are handled differently across the codebase - > Use Express error handlers instead - Migrate from callbacks to async-await
16. Error handling - Express app.get('/users/:id', (req, res, next) => { const userId = req.params.id if (!userId) { const missingIdError = new Error('Missing id') missingIdError.httpStatusCode = 400 return next(missingIdError) } Users.get(userId, (err, user) => { if (err) { err.httpStatusCode = 500 return next(err) } res.send(Users) }) })
17. Error handling - Express app.use((err, req, res, next) => { // log the error... res.sendStatus(err.httpStatusCode).json(err) }) Add an error handler middleware as the last one
18. Error handling - Express const missingIdError = new Error('Missing id') missingIdError.httpStatusCode = 400 next(missingIdError) $
20. Error handling - Express const boom = require('boom') app.get('/users/:id', (req, res, next) => { const userId = req.params.id if (!userId) { return next(boom.badRequest('missing id')) } Users.get(userId, (err, user) => { if (err) { return next(boom.badImplementation(err)) } res.send(Users) }) })
21. Error handling - Express const asyncMiddleware = fn => (req, res, next) => { Promise.resolve(fn(req, res, next)).catch(next); }; module.exports = exports = asyncMiddleware; Wrapping the Express route handlers for proper error propagation
22. Error handling – Express The modified error handler app.use((err, req, res, next) => { if (err.isServer) { // log the error... // probably you don't want to log unauthorized access // or do you? } return res.status(err.output.statusCode).json(err.output.payload); })
23. Error handling - Express app.get('/users/:id', asyncMw((req, res) => { const userId = req.params.id if (!userId) { throw boom.badRequest('missing id') } const users = await getUserAsync(userId) res.json(users) }))
24. Error handling - Express app.get('/users/:id', asyncMw((req, res) => { const userId = req.params.id if (!userId) { throw boom.badRequest('missing id') } const users = await getUserAsync(userId) res.json(users) })) app.get('/users/:id', (req, res) => { const userId = req.params.id if (!userId) { return res.sendStatus(400).json({ error: 'Missing id' }) } Users.get(userId, (err, user) => { if (err) { return res.sendStatus(500).json(err) } res.send(users) }) })
25. Error handling - Express • Have unified error handling • Start using async-await with throw and try-catch
26. Securing your application
27. Securing your application
28. Securing your application Enable two-factor authentication for your npm account
29. Securing your application More than 500,000 modules in the registry
30. Securing your application
31. Securing your application
32. Securing your application
33. Securing your application • Node Security Project: security advisories • Snyk: Vulnerability DB
34. Securing you application Security HTTP header • X-Frame-Options to mitigates clickjacking attacks, • Strict-Transport-Security to keep your users on HTTPS, • X-XSS-Protection to prevent reflected XSS attacks, • X-DNS-Prefetch-Control to disable browsers’ DNS prefetching.
35. Securing you application Security HTTP header const express = require('express') const helmet = require('helmet') const app = express() app.use(helmet())
36. Securing you application Validating user input const Joi = require('joi'); const schema = Joi.object().keys({ username: Joi.string().alphanum().min(3).max(30).required(), access_token: [Joi.string(), Joi.number()], birthyear: Joi.number().integer().min(1900).max(2017), email: Joi.string().email() }).with('username', 'birthyear') // Return result const result = Joi.validate({ username: 'abc', birthyear: 1994 }, schema) // result.error === null -> valid
37. Logging best practices
38. Logging best practices Requirements • Timestamps to know when a given event happened, • Format to keep log lines readable for both humans and machines, • Destination should be the standard output and error only, • Support for log levels
39. Logging best practices Using log levels • Error • General errors, always reported • Used whenever an unexpected error happens which prevents further processing • The app may try to recover (like on database connection lost) or forcefully terminate
40. Logging best practices Using log levels • Warn • For events indicating irregular circumstances, with clearly defined recovery strategy • It has no impact on system availability or performance • These events should be reported too
41. Logging best practices Using log levels • Info • These events indicate major state changes in the application, like the startup of the HTTP server • Each component should log: • When it starts and when it became operational • When it started shutdown, and just before it stopped
42. Logging best practices Using log levels • Debug • Diagnostical level events, for internal state changes • These events are usually not reported, just for troubleshooting • At the discretion of the engineer developing the system component
43. Logging best practices Example logger.info('server started initializing ') const app = express() app.get('/', (req, res) => { res.send('ok!') }) app.listen(PORT, (err) => { if (err) { return logger.error(err) } logger.info(`server started listening on ${PORT}`) })
44. Logging best practices Log the original URL of the request for errors app.use((err, req, res, next) => { if (err.isServer) { logger.error(err.message, { stack: err.stack, originalUrl: req.originalUrl }) } return res.status(err.output.statusCode).json(err.output.payload); })
45. Building a CICD pipeline
46. Building a CICD pipeline • Protect the master branch • Only approved pull requests can be merge • Contributors with write access can approve
47. Building a CICD pipeline • Run automated checks on your codebase: • Linting • Unit, integration, functional tests • Code coverage
48. Building a CICD pipeline • With good test coverage • You can deploy to production on every commit • Reduced risk • Faster reaction times • Flexible release options
49. Monitoring your applications
50. Monitoring your applications Most important metrics to watch • Error rate, as they directly affect customer satisfaction; • Latency, as the slower the service, the most likely your customers close your application; • Throughput, to put error rate and latency in context; • Saturation, to tell if you can handle more traffic.
51. Monitoring your applications How your app is doing?
52. Monitoring your applications Aggregated metrics have little value
53. Monitoring your applications You want to have route-level metrics This way of monitoring is called white box monitoring Tools like Prometheus, New Relic, Opbeat or Dynatrace can help to implement it.
54. Monitoring your applications Can users access it? This way of monitoring is called black box monitoring Tools like Pingdom or ping.apex.sh provides these services.
55. Incident handling
56. Incident handling You build it, you run it
57. Incident handling You build it, you run it • Teams will think about how their software is going to run in production • Encourages ownership and accountability which leads to more independent, responsible teammates • Leads to operational excellence • Which leads to more satisfied customers
58. Incident handling When all hell breaks loose • Have a “War Room” / “On call” channel in your instant messaging system • When the issue happens, notify your customers through a status page, keep it up-to-date through the investigation • Do post-mortems on what led to the issue, and what actions will be taken to prevent it in the future
59. Incident handling The human aspect • At least 3 people for a 24/7 schedule • With distributed teams you can minimize night shifts • Set up a pager with escalation policies • Have a secondary team on standby
60. Incident handling The human aspect • A fair number of is one or two issues per on-call shift • With more, you risk: • Burning-out your team • Decreasing the work quality because of the focus lost • With less, they may lose touch with the production system
61. Summary • How to handler errors is Node.js using async-await • The most important tasks automated by a CI/CD pipeline • Logging and monitoring best practices • Incident handling
62. Thanks! I’ll be around, just say hi if you want to talk
63. Oh, and we are hiring! I’ll be around, just say hi if you want to talk https://careers.godaddy.net/
64. Resources • https://blog.risingstack.com/node-js-logging-tutorial/ • https://nemethgergely.com/nodejs-security-overview/ • https://nodesecurity.io/ • https://wiki.opendaylight.org/view/BestPractices/Logging_ Best_Practices • https://blog.risingstack.com/node-js-security-checklist/