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:
DrupalCamp CT 2016
Full Slidedeck with Speaker Notes:
https://github.com/milsyobtaf/prez/raw/primary/2016/DrupalCampCT/opening-the-black-box_notes.pdf

Transcript

1. DrupalCamp CT 8/20/2016 Opening The Black Box
2. Howdy! Dustin Younse @milsyobtaf I’m an engineer at Four Kitchens
3. DrupalCamp CT 2014 DrupalCamp CT 2016 (morning) DrupalCamp CT 2016 (afternoon) I guess I’m an Ivy League assistant professor now?
4. What Is The Black Box?
5. • Non-technical education • Self taught web skills • Above average Googling abilities • Late nights staring at error messages A Familiar Story?
6. Mental Model of Drupal
7. Mental Model of Drupal
8. Mental Model of Drupal
9. Mental Model of Drupal
10. Mental Model of Drupal
11. Start At The Beginning
12. Text Editors • “Text Editors” • Text Editors • IDEs
13. • Text Edit (Mac) • Notepad (Windows) • Nano (Linux / Mac) “Text Editors”
14. • Notepad++ (Windows) • vim (Mac / Linux) • Dreamweaver (Mac / Windows) • Sublime Text (Mac / Linux / Windows) • Atom (Mac / Linux / Windows) Text Editors
15. • PHPStorm (Mac / Linux / Windows) • Eclipse (Mac / Linux / Windows) • Komodo (Mac / Linux / Windows) Integrated Development Environments
16. Development Environments • On your server • On your machine • On your machine, but it acts like the server
17. Development Environments • FTP Development • “Cowboy coding” • Local Environments • MAMP / LAMP / Vagrant • Next generation • Kalabox
18. • FTP Development • “Cowboy coding” • No version control up front • Little debugging visibility • Log files (maybe), debug statements • Watchdog logs (maybe) FTP Development
19. • 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
20. • 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
21. • Kalabox with Pantheon / Acquia integration • Custom Vagrant boxes (DrupalVM) • print_r(), dsm(), xdebug • Very accurate performance profiling • XHProf Local Development: The Next Generation
22. Something Is Broken!
24. Relax.
25. Remember Cobble’s Knot
26. • 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?
27. • 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
28. • Custom Module • Theme template.php • Theme Template Where Is It Broken?
30. The Scientific Method
31. • Change one thing at a time • Test that change • Repeat Finally, Debugging
32. • Save your progress as you work • Recreate your Features • Makes rabbit holes manageable git Is Your Friend
33. • 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
34. git blame Finds Your Enemies
35. git blame Finds Your Enemies
36. • 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
37. Make The Future Easier
38. • watchdog() (D7) • \Drupal::logger() (D8) • syslog Module • http://loggly.com • https:/ /www.elastic.co/blog/heya-elastic-stack-and-x-pack • Write a test! • Simpletest • Behat Proactive Debugging
39. @milsyobtaf
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.