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
   

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2. Hi, I am Gergely.
   ■ Works at GoDaddy
   ■ Previously RisingStack
   ■ To chat with me:
   – @nthgergo
   – mail@nemethgergely.com
   ■ Read my stuff:
   – nemethgergely.com
   

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3. Node.js Production Checklist
   Gergely Nemeth
   @nthgergo | nemethgergely.com
   

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4. Why do you need a production
   checklist?
   

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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
   

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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
   

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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
   

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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
   

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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
   

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10. Error handling
    

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11. Error handling
    

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12. Error handling
    Async-await changes how we
    write Node.js applications
    

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13. Error handling
    You have to learn to throw
    again
    

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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)
    })
    })
    

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15. Error handling - Express
    - Errors are handled differently across the
    codebase
    - > Use Express error handlers instead
    - Migrate from callbacks to async-await
    

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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)
    })
    })
    

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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
    

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18. Error handling - Express
    const missingIdError = new Error('Missing id')
    missingIdError.httpStatusCode = 400
    next(missingIdError)
    
    
    
    $
    

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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)
    })
    })
    

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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
    

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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);
    })
    

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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)
    }))
    

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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)
    })
    })
    

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25. Error handling - Express
    • Have unified error handling
    • Start using async-await with throw and try-catch
    

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26. Securing your application
    

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27. Securing your application
    

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28. Securing your application
    Enable two-factor authentication for
    your npm account
    

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29. Securing your application
    More than 500,000 modules in
    the registry
    

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30. Securing your application
    

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31. Securing your application
    

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32. Securing your application
    

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33. Securing your application
    • Node Security Project: security advisories
    • Snyk: Vulnerability DB
    

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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.
    

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35. Securing you application
    Security HTTP header
    const express = require('express')
    const helmet = require('helmet')
    const app = express()
    app.use(helmet())
    

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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
    

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37. Logging best practices
    

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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
    

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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
    

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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
    

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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
    

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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
    

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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}`)
    })
    

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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);
    })
    

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45. Building a CICD pipeline
    

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46. Building a CICD pipeline
    • Protect the master branch
    • Only approved pull requests can be merge
    • Contributors with write access can approve
    

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47. Building a CICD pipeline
    • Run automated checks on your codebase:
    • Linting
    • Unit, integration, functional tests
    • Code coverage
    

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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
    

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49. Monitoring your applications
    

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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.
    

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51. Monitoring your applications
    How your app is doing?
    

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52. Monitoring your applications
    Aggregated metrics have little value
    

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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.
    

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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.
    

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55. Incident handling
    

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56. Incident handling
    You build it, you run it
    

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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
    

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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
    

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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
    

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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
    

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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
    

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62. Thanks!
    I’ll be around, just say hi if you want
    to talk
    

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63. Oh, and we are
    hiring!
    I’ll be around, just say hi if you want to talk
    https://careers.godaddy.net/
    

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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/
    

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