Opening The Black Box

Trying to tame a modern, fully-featured web application like Drupal can be an exercise in frustration.

Why are you printing that piece of content there?
Why am I seeing a negative integer instead of a string from this function?
What could a PDOException in my Watchdog log possibly mean?
In this session, we will be going over useful debugging tools and techniques that can help you start to see into the inner workings of all versions of Drupal, including the new kid on the block, Drupal 8. You will be better prepared to start building truly custom features into your projects and you’ll be able to remain calm when you get the ineveitable email that your site is showing the dreaded White Screen Of Death at 4:45pm on a Friday afternoon.

Presented at:
BADCamp 2015
Full Slidedeck with Speaker Notes:
https://github.com/milsyobtaf/prez/raw/primary/2015/BADCamp/opening-the-black-box_notes.pdf

Transcript

1. BADCamp 10/23/15 Opening The Black Box
2. I’m an engineer at Four Kitchens Howdy! Dustin Younse @milsyobtaf
3. q
4. S
5. What Is The Black Box?
6. • Non-technical education • Self taught web skills • Above average Googling abilities • Late nights staring at error messages A Familiar Story?
7. Mental Model of Drupal
8. Mental Model of Drupal
9. Mental Model of Drupal
10. Mental Model of Drupal
11. Mental Model of Drupal
12. Start At The Beginning
13. Text Editors • “Text Editors” • Text Editors • IDEs
14. • Text Edit (Mac) • Notepad (Windows) • Nano (Linux / Mac) “Text Editors”
15. • Notepad++ (Windows) • vim (Mac / Linux) • Dreamweaver (Mac / Windows) • Sublime Text (Mac / Linux / Windows) • Atom (Mac / Linux / Windows) Text Editors
16. • PHPStorm (Mac / Linux / Windows) • Eclipse (Mac / Linux / Windows) • Komodo (Mac / Linux / Windows) Integrated Development Environments
17. Development Environments • On your server • On your machine • On your machine, but it acts like the server
18. Development Environments • FTP Development • “Cowboy coding” • Local Environments • MAMP / LAMP / Vagrant • Next generation • Kalabox
19. • FTP Development • “Cowboy coding” • No version control up front • Little debugging visibility • Log files (maybe), debug statements • Watchdog logs (maybe) FTP Development
20. • print_r() • Raw dump of a variable or context, no formatting • print_r($node); • <pre><?php print_r($node); ?></pre> • dsm() • Formatted dump of a variable or context • dsm($node); Debug Statements in Code
21. • MAMP / Dev Desktop / Native LAMP • Code runs entirely locally • Added bonus of offline work, no internet required • print_r(), dsm(), but also more • xdebug Local Development
22. • Kalabox with Pantheon / Acquia integration • Custom Vagrant boxes • print_r(), dsm(), xdebug • Very accurate performance profiling • XHProf Local Development: The Next Generation
23. Something Is Broken!
25. Relax.
26. Remember Cobble’s Knot
27. • Is something not showing up? • New content - is it published? • Old content - are permissions set properly? • Is something showing up that shouldn’t? • Raw HTML and Javascript in a WYSIWYG field? What’s Broken?
28. • Log Files • You should learn how to find your log files 
 before you need your log files • multitail • Linux / Mac utility to easily view logs
 with more options than tail Work From The Bottom Up
29. • Custom Module • Theme template.php • Theme Template Where Is It Broken?
31. The Scientific Method
32. • Change one thing at a time • Test that change • Repeat Finally, Debugging
33. • Save your progress as you work • Recreate your Features • Makes rabbit holes manageable git Is Your Friend
34. • Remove your debug statements • Ensure you only changed as much as you 
 needed to change • You only commit dsm(‘Butts’); to master once git diff Is Your Friend
35. • Can help you track down who wrote 
 the offending code • This should not be a witch hunt • This should be a chance to find 
 context for the issue git blame Is Your Friend
36. Make The Future Easier
37. • watchdog() (D7) • \Drupal::logger() (D8) • syslog Module • http://loggly.com • Write a test! Proactive Debugging
38. We’re Hiring!
39. http:/ /fourkitchens.com/careers
40. Thank you! All content in this presentation, except where noted otherwise, is Creative Commons Attribution-ShareAlike 3.0 licensed and copyright Four Kitchens, LLC.