I've mentioned before how much I like TeamCity, but I didn't really talk about how we use it. Just recently Jacob completed some work on multiple build configurations that make our life much easier. I thought I'd go over them here to give you an idea of how we handle continuous integration here.
Continuous Integration configurations
- CI - Trunk - This is the CI configuration everyone has. This watches the trunk of our SVN repository and builds whenever it changes it will also run our database migrations against the CI trunk database. It has all our built assemblies as artifacts. The artifacts take up a lot of space so we don't keep them around that long.
- CI - Published - This is just like CI - Trunk, but it watches our published branch, which is where we put everything that we're about to publish to the live site. We keep two branches so that we can make quick fixes to the published site without having to publish new features we're working on. This has its own database that is migrated.
- Nightly - Trunk - This runs daily rather than watching our source control. It migrates a database on our production database server that is a copy of our live database. It also builds and deploys the trunk to a test address on our production servers. This allows our team in Korea and our stakeholders to see changes every day in a safe environment. The Nightly is also a big part of our localization story, which I'll save for another post.
Database build configurations
- Snapshot - This and the other db build configurations probably deserve their own post with more details, but I'll do my best to explain these briefly. The Snapshot build configuration takes a point in time snapshot of the database and packages it into a zip file. The zip file becomes a TeamCity artifact that other projects can depend on.
- Nightly/CI Trunk/CI Published Baseline -
These configurations import database snapshots into the database they refer to. The only time we need to do this is if a bad migration runs, or we want to "refresh" the data inside the database.
It is important to note that we do not run CI - Trunk on a complete snapshot of the live database. When we do, it greatly increases the build time because our integration tests run significantly slower in a real database. Instead, we import a "light" database which contains all of the tables, but only the data from our static tables. The users, records, and anything else that grows as we get more and more users are just left empty. This means that we have zero sample data for these things during our integration tests, so we rely heavily on Fluent Fixtures to set up sample data.
The other two databases do run nearly complete copies of the live database (we exclude log tables basically), so we still get to test our migrations and our site on real data.
Utility build configurations
- StatSVN - Runs StatSVN on our codebase. Somewhat useful source statistics. Mostly use it to see growth and churn.
- Duplicate Finder - Haven't really done this much to be honest, but TeamCity has build configurations whose sole purpose is finding duplicate code.
I'm completely enamored with this set of configurations. It makes so many things so painless. We still have room for improvement, managing all of the configuration differences in the sites is difficult. We also lack a one click live publish ability. We still follow a manual script for that, which is error prone and dangerous.