An iOS Continuous Integration Machine Is Not A Pet

An iOS continuous integration machine should not be a pet. Do you know what I mean by a “pet?” Have you heard the analogy for determining whether a server is a pet or cattle? Continuous integration machines should be treated like cattle, not pets.

iOS Continuous Integration

Without trying to sound cruel or inhumane, when cattle get sick, you can quickly replace it. When pets get sick, you spend a lot of time and money to try and help them get better. Now apply this to your continuous integration machine. If you have a dusty old Mac Mini sitting next to you that is acting as your continuous integration machine, eventually the hard drive is going to die or any other myriad of problems. Do you want to be in the business of resuscitating the machine when that happens? Not me, I’d much rather be focusing on what matters, writing awesome new features for my end users.

CI Should Not Get In Your Way

Imagine this scenario: you’ve been coding all night, and finally you get that hot new feature done, tests pass locally, and you’re ready to open a pull request. You push your branch, and for some reason Wolfie, your build server, isn’t powered on and won’t start up. Now your choice is to either spend time trying to fix Wolfie, or skip your whole iOS continuous integration workflow. What would you do?

Regardless of the choice that you made in that scenario, the point is, your CI server should be waiting to serve your needs, perfectly, every time. And if you are relying on some old piece of hardware lying around your home or office or home office, chances are, you’re going to spend more time caring and feeding for it, that you would if you had managed it as a disposable resource that can easily be replaced.

Don’t Waste Your Time

As tempting as it is to tryout Xcode Server on that old Mac you have lying in your garage collecting dust and rusting, I propose that you don’t waste your time keeping old Wolfie the build server around or even introducing him in the first place, and instead consider approaches where you aren’t in the business of maintaining your own hardware or an isolated build software stack. There’s two paths you can take towards this: all-in-one hosted CI solutions, or configuring an automated deployment of your CI environment to use something like Mac Mini colocation where you can spin up Mac Minis on demand to build your application. Here’s an overview how DayOne used in conjunction with Jenkins for their builds. Want to run your tests on actual devices? Well then you could even write a script to automatically provision devices from Amazon Device Farm and run your tests on them. This approach grants you the most granularity and flexibility in your configuration, but takes a lot more effort to develop. You need to write the scripts that do the server provisioning, so that they are available and dependable in a repeatable fashion.

Sound like too much work? Alternatively, hosted iOS continuous integration solutions have been coming onto the scene lately and look very promising in that they advertise simplistic wizard-based setup of your CI jobs. Basically, login with your GitHub credentials (or Bitbucket), select your project, and click Build. Tomorrow, I’m going to give you an overview of buddybuild which is one of the hottest players on the market now in this area.

In the meantime, happy cleaning.

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