Keep Drupal Running With Continuous integration

Keep Drupal Running With Continuous

Integration

Mike BoothNYC Camp 2012

Saturday, July 21, 12

“Why can’t we edit our settings directly

on the production server?”


Why We Don’t Just Develop On Production Servers

Visitors dislike broken thingsHard downtimeData corruptionRollbacks are slow & they lose new dataNo audit trail

Hard to document changesHard to discuss changes


Hacking On Live Websites Is Awesome

Focus

One place to goOne set of knobs to turn

Short Cycle Time

Everyone looks for bugsBugs triage themselvesApplause arrives in real time


It’s So Awesome, We Maintain Dozens of Control Panels For It


Hacking On Live Websites Would Be Awesome

If Only It Didn’t CauseExpensive Disasters


“What’s the next best thing?”


What we actually do

Make copies of the site and develop with them

Copy the code

Copy or simulate DB and files

Run on a separate dev server


The Problem

Integration(The art of resolving

inconsistencies.)


Integration1. Everyone works on a copy.2. Announce a “freeze”.3. Collect copies and mix together.4. Test, find bugs, point fingers, fix bugs. 5. Iterate Step 4 until confident.6. Cross fingers. Upload result to production. 7. Fix more bugs, urgently.8. Go to Step 1.


Continuous Integration

Do this several times a day.


The Story of CI

1. Go to main branch & check out working code.2. Build a patch that passes all tests.3. Update from main branch, make tests pass.4. Commit to main branch ASAP.5. Make tests pass on an integration machine.6. [Optionally, release to production: see Continuous Deployment]

7. Go to Step 1.


Integration1. Everyone works on a copy.2. Announce a “freeze”.3. Collect copies and mix together.4. Test, find bugs, point fingers, fix bugs. 5. Iterate Step 4 until confident.6. Cross fingers. Upload result to production. 7. Fix more bugs, urgently.8. Go to Step 1.


Use version controlPut everything in there.

But don’t use too much version control:

Private branches are okay

There should be one main branch

It should live at a canonical source

Other branches should have brief lives


Make the main branch available to everyone

A friendly tarball is nice

Github can help you

A running server is nicer

Update this on every commit


Every Commit Must Pass Integration Tests

These are not run on your dev machine

Although those should’ve passed too

Run separate integration-testing machines

Your commit is not finished until the main branch passes these tests


Run Integration Tests on A Clone of Production

Same hardware.

Same OS and software stack.

Same versions of everything.

Database as similar to production as possible.

Scrubbed production DB

Script-generated test data

Virtualization is your friend.


Automate DeploymentYou’ll be deploying a lotConsistency is vitalAutomate every layer:

OS and web stack (e.g. Puppet)Code deployment (e.g. Capistrano)DB updates (Drupal update functions)

Acquia Cloud, Pantheon, etc. can help you


Automate Testing

You’ll be testing a lot

Every bit you do will help.

Smoke tests

Browser-simulation (e.g. Selenium)

Test the showstoppers

Test things which broke once before


“CI” ≠ “Jenkins”

But Jenkins can help(Or CruiseControl, Travis CI, Buildbot, etc.)

“Continuous Integration is an attitude, not a tool” - James Shore


Commit Very Often

Standard: Everyone commits once per day

Or more

Practice doing work in smaller pieces


Builds Must Be Fast

Seconds = superb

Five to Ten Minutes = fine

An hour = awful

Many hours = disastrous


OMG My Builds Take Three Days

Consider a deployment pipeline

Stage 1: minimalist tests, fast

Stage 2: slow

Stage 3: wicked slow

A commit to main branch:

Must pass Stage 1 in advance

Triggers Stage 2; failures must be fixed ASAP


Display the Results to Everyone

Status review during scrum meetings

Usable web dashboards

Control-room displays


Lava Lamps

http://www.pragmaticautomation.com/cgi-bin/pragauto.cgi/Monitor/Devices/BubbleBubbleBuildsInTrouble.rdoc






Rubber Chicken

http://jamesshore.com/Blog/Continuous-Integration-on-a-Dollar-a-Day.html




BLAME-SEEKING ENGINE OF DOOM

http://www.papercut.com/blog/chris/2011/08/19/who-broke-the-build/




You’re Gonna Love Continuous IntegrationReduced Risk

Process Visibility

Fewer Bugs

Easier Debugging

Easier Rollback

Less Wasted Effort


Credits

The Acquia Cloud team

Martin Fowler“Continuous Integration”www.martinfowler.com/articles/continuousIntegration.html


Keep Drupal Running With Continuous integration

Technology

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