Drupal and Continuous Integration

Continuous Integration (CI) is the practice, in software engineering, of merging all developer working copies with a shared mainline several times a day [1]. Implementing CI in Drupal 7 can be tedious, but I will go into some of the tools and techniques we use at Princeton University to implement a CI workflow.

In this session we will explore some of the benefits and advantages you get from implementing CI, along with sample workflows and tools, such as Git, Jenkins, and the Drupal Features module.

[1] https://en.wikipedia.org/wiki/Continuous_integration

Transcript

1. Drupal and Continuous Integration DrupalCampNJ - 2014
2. Who we are Henry Umansky Princeton University humansky@princeton. edu Jason Howe Drew University jhowe@drew.edu
3. What is Continuous Integration? “Continuous Integration is a software development practice where members of a team integrate their work frequently, usually each person integrates at least daily - leading to multiple integrations per day.” -Martin Fowler
4. Principles of CI? • Maintain a code repository • Automate the build • Make the build self-testing • Everyone commits to the baseline every day • Every commit (to baseline) should be built • Keep the build fast
5. Principles of CI (cont’d) • Test in a clone of the production environment • Make it easy to get the latest deliverables • Everyone can see the results of the latest build • Automate deployment
6. Advantages of CI • prevent integration problems • identify failing code early • immediate unit testing of all changes • "current" build for testing, demo, or releases
7. Disadvantages of CI • Initial setup time required • Well-developed test-suite required to achieve automated testing advantages
8. Maintain a code repository • Version Control Systems: git or svn • use Features as much as possible • Strongarm Module
9. Automate the Build • Hudson/Jenkins • Drush • Build triggers
10. Make the build self-testing • Drupal Coder Review/Security Review • Code Quality - [ php | css | js ] lint • PhantomJS and Selenium • Checkstyles/PHPMD
11. Daily Commits • Commit at least once a day • Reduces potential conflicts • Triggers automated builds
12. Demo
13. Automated Deployment • Identical /dev/qa/prod systems • Trivial to move code between environments • Single button click to perform complex tasks
14. Automated Deployment • Single button click to deploy production code to n webservers. • Deployment is simply a “git pull”, executed via remote ssh. • Auto deployment to dev upon code commit to dev.
15. Achieving Identical Environments • Everything has to be automated, no lovingly handcrafted environments. • Bash script fired by Jenkins, builds databases, instantiates drupal instance in all environments. • Tools to sync content from prod->dev and code from dev->prod
16. Known state of environments • You always know that Dev contains everyone’s latest contributions. • You always know that Prod is a copy of what’s in the repo.
17. From the Operations Perspective • Keep Server configs in (my.cnf, http.conf, etc) in a configuration repository. • New webhead is trivial: ◦ checkout config repo and run setup script. ◦ symlinks config files, checkout drupal. ◦ Essentially a self-configuring server • Works for DR too!
18. Other Advantages for Ops • Knowing, without a doubt the current system state. • Ability to spin up a test environment in minutes. • Aids in troubleshooting and quick issue resolution. (Good comments commits help too)
19. Questions?