Tuesday, July 15, 2008

Continuous Integration in TFS 2008: Part 1

Many people now accept the benefits of a regular / continuous integration cycle (even if they don't actually practice it themselves). Picking up the pieces after someone's broken the checked-in source code, especially if it's not picked up for a few days, can be a real time waster.

Like many agile practices, however, the cost / benefit is hard to quantitatively analyse. It's far easier to justify therefore if it's really easy to setup: as the costs tend to zero the benefits become essentially 'free'. And you could argue that tools like CruiseControl.Net have made it pretty easy.

Personally, having spent significant sections of the last 3 years getting CCNet / Nant build cycles going on various projects, I'd beg to differ. Sure, it's really easy to setup CCNet / Nant (or CCNet / MSBuild) to build your solution, but that's only the first step in the process. Typically you also want to do things like:
  • Import the latest built version of external dependencies (ie components maintained outside of the solution being built)
  • Execute unit tests
  • Execute integration tests (so config files pointing at databases etc... have to be in the right place)
  • Package the build outputs nicely ('xcopy ready')
  • Deploy and install into test environments
CCNet and NAnt don't really give you this stuff 'out of the box'. You spend time gluing bits together, inventing your own build process and so on, and maintaining this stuff seems to get out of control very easily. Deploy and install is a particular minefield, because somewhere in there you have to start doing configuration file substitution (put your test server settings in the web.config etc...). And doing all this in XML just rubs salt into the wound.

You can handle most of this by hand on small projects, but the last app I worked on had five or six deployable parts to it (webservices, windows services, Winforms with ClickOnce manifests and the like), each of which had 20 or so settings to change for each of 7 different environments and the differing systems it integrated with. That's 100's of settings to keep track off, without even getting into the Biztalk artefacts, and that was only one of several projects of similar complexity. Automation's a no brainer at that point.

My solution to try and scale back the per-project cost of managing this was my own open source project SNAK. This attempted to commoditize a standard build / test / package / deploy process that you could implement on your side by pretty much setting a single variable at the top of a build script. And I think it works reasonably well: but it's clearly not the answer, not least because it took a fair amount of my (and others) time, of which I have very little.

So I was very, very hopeful when I started looking at the CI support in TFS 2008. Microsoft were really bashed over CI (lack of) in 2005, but this time round it looks like they've delivered:

You pretty much pick your solution file:

...your output directory...

...and your build frequency, and off you go:

Given how hard it was to deal with VSTS tests under CI in 2005 (because the test file was always in the wrong place), this screen will be a real pleasure to some:

And if you've tried to implement a build output retention policy in NAnt, you'll really appreciate this:

So up until now, absolutely fantastic. But then I had a few issues, which I'll deal with in Part 2 (so as not to take the gloss off the good bits above).

[I was due to present on this topic at the Perth .Net user group the other week, but a failing laptop saw to that (not the way I was expecting the demo to fail!). Since there's now no slots till Xmas, I've recycled some of the content into this post. The laptop was lobotomized and is recovering well...]

[Readify are doing a Dev Day in Perth on the 29th, with TFS as one of the tracks, so I'd be surprised if they didn't cover this there]

1 comment:

Justin Kohnen said...

I like where you're going with the article. I can't wait to see part 2.

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