Django production
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The document provides essential guidelines for launching a production Django application, emphasizing common pitfalls, performance tuning, security considerations, and post-launch maintenance. Key recommendations include thorough testing, optimizing performance using tools like memcached and New Relic, and ensuring content and browser compatibility. It also highlights the importance of a well-structured deployment process, configuration management, and ongoing maintenance to ensure a successful and stable application launch.
Django production
- 1. So, You Want to Make a Production Django App
- 2. A Little Background • Launching Production Django Apps since '06 and 0.9something beta • Launched and Managed Django Websites, E- Commerce Sites, and Web Apps for brands such as: • Rip Curl, UT San Diego, Callaway Golf, DC Shoes, Dunlop, PacSun, and many many more
- 3. Goals • Identify Common Pitfalls in Launching • Point Out Django Gotchas • Point Out Django Tools • Help You Have a Smooth Launch • Give Some Pointers on Managing and Maintaing a Django App
- 4. This Only Partially About Django and all about launching web apps
- 5. Going Production is... • Putting it in front of consumers • Promoting It • Customer data • 24/7/365 • Someone Else Is Using It • Your billing relationship changes
- 6. But First, Some Quick Tips
- 7. Simple Django Things • DEBUG = False • Style your 500 / 404.html • HTTPS Admin, login, and .. anywhere sensitive information is submitted • Make your Sites record accurate
- 8. Simple Non-Django Things • Favicon • Run a Site Crawler • Redirect to one domain - www • Check your browser console for errors
- 9. So What Makes Your App Ready?
- 10. The Big Questions • Is it Stable? • Did I get it Right? • Does it Perform?
- 11. Stability • Stability is about predictable performance • Thorough testing • A way to track bugs and issues • A way to monitor what's happening
- 12. Bug Tracking • 500 Emails - Send these to a Gmail Account • Sentry is cool • Rotate your logs • Stomp 500s, signal to noise is very important
- 13. Refactoring • You probably didn't get all the data models and functionality right • Following launch focus on fixing issues, not solving any misconceptions.
- 14. Ok, App Works Good, Until the Newsletter Went Out
- 15. Performance part 1 • Memcached + ANONYMOUS_CACHE • Django Debug Toolbar • {% cache %} • But, don't cache session specific stuff! • Use Production Scale Data
- 16. Performance part 2 • We use Nginx + Gunicorn • CDNs - use them, but use caution • Expire Tags - speed without effort • Premature Optimization is the root of all evil, but the night before launch is no longer premature, so save it in a temporary model on a signal damnit
- 17. Performance 2.1 • Our Setup • Static Media from CDN • Nginx or ELB or other load balancer • Gunicorn managed by Supervisord • MySQL or Postgresql • Memcached, Elasticsearch, RabbitMQ
- 18. Performance part 3 • New Relic can tell you a lot • Process long tasks with Celery • Varnish can do wonders, if your app is doing the right thing • But first optimize your queries and indexes • Yes, you can do group bys and aggregates.. annotate and aggregate are not so intuitive • DB Templates Are Expensive
- 19. Aggregate Digression RateClass.objects.annotate( hours = Sum("person__timeentry__hours")).filter( person__timeentry__project__name="My Project') )
- 20. But Enough About Performance • Performance is usually something you see as you scale up and add complexity • Your site should perform quickly, but even more importantly..
- 21. Things That Really Matter
- 22. Content! • Is all the content the right content? • No Lorem Ipsum • Do all your forms submit? Are there human error messages. • Is the contact information correct?
- 23. Browser Compatibility • Did you check all your browsers? • As a rule, CEOs use the oldest possible IE version • There are over 100 million iPads, what does your site look like on one? CEOs usually have one of these too.
- 24. Security • SSL logins! admins! everything! • CSRF protection • Are you assuming anything?
- 25. Search Matters • robots.txt • canonical tags • meta tags • analytics tags • duplicate content
- 26. What Used to Be Searched Also Matters • Pages with rankings are valuable • If it was a link on Google, don't make it a 404
- 27. Things You Should Have Already Done
- 28. Training • Not everyone groks abstractions, explain how to do things • Make sure your client knows that access to Users == Super User • Take a moment to polish your Change List and Change Form Templates
- 29. Dev Site • Have one • Make sure it doesn't send email to anyone • Make sure it says "DEV SITE" somewhere on the front end • Make sure it has robots.txt disallowing all • If possible, control access • Keep track of any integration credentials for sandbox vs production
- 30. Configuration Management • Settings Can Get Unruly • We use cascading imports to structure them • Beware Stored Passwords!
- 31. Testing • Unit Tests are nice, if you have been doing them all along • Test it by hand • Test it like a consumer • - Bad / Missing Data • - International Data / Unicode
- 32. Migrations • Use South, or don't but be prepared to tear your hair out either way • Is there existing data to import? Do a dry run - build this into management commands
- 33. Ok We Are Ready!
- 34. Launch is in 1 week • Lower your DNS TTL • Make sure you have access to all the domain information • Are all integrations ready for production? With production credentials? • A Dry Run is worth the effort • Do you know all the DNS records you are changing? Are the nameservers in your control? • Test your site with /etc/hosts, make sure it is ready to go • Write up a plan, and let everyone know the timing
- 35. Launch! • Sometimes, it is better to just get it done. • But not always • But sometimes, really, it just has to fly • Walk through everything • Run transactions on your credit card, and then cancel them • Doubt everything
- 36. Deployment • Revision your deploys with Git • Automate it as much as possible • But don't put off automating most of it • Read the 11-Factor App
- 37. DNS Gotchas • Nameservers! Don't change unless you know all the records that are there • SPF, PTR - make sure your email makes it through the spam filter • IT departments don't get CNAMEs, so watch your load balancers!
- 38. Woo Hoo! It's Up! Now What Are We Done?
- 39. Post Launch • Keep track of what you agreed to build. • Good fences make good neighbors • When You Launch, You are in Maintenance Mode. Make the Mental Shift!
- 40. Refactors, Again • Actually that did need to be a separate model • See, South was a good idea • Ouch you should have used South • Either way, you need to write a manage command
- 41. Maintenance Tips and Tricks • Manage commands are really useful • So is the shell • Know what you plan to do on a server before logging in
- 42. The Long View • Don't focus on the bad things, focus on what was achieved • What simple things can you do to make the next one smoother • Checklists!
- 43. Questions?