Dependency Management

With most software projects these days, including open source components is almost a given. There is no reason to reinvent the wheel and some components are so customized that it would take months to mimic the behavior. There are many ways to integrate these components into an application. One of my mantra when working on projects is that I just want to be able to checkout the project from a repository and build it; there shouldn’t be several steps and I shouldn’t have to worry about something outside of my control breaking the build.

Years ago when I worked on a particular project, there was a several step process to just get the source code which integrated open source components. This was extremely fragile as the references to the open source components was for an external repository that could go away at any time. When I became in charge of the project, I changed things so that we only relied on repositories that were under the control of the company (we had shared components).

In iOS development, there are now 2 (or 3) main systems for managing these external dependencies. The first is CocoaPods which is very popular, but relies on the external repositories to always be there and requires modifications to how the project is built. The newer entrant into this arena is called Carthage. Carthage gives me more control on the dependencies. The system makes it easy to store the dependencies in my repo and easily update them. In particular, I use the following command to update

carthage update --platform iOS --no-build

Basically I just let Carthage update the components and I have my project setup to do all the builds. When I checkout the project, it has everything in it and I just build. I think that this setup, at least currently, strikes the best balance to handling dependencies.

The other day I was reminded of this problem when a developer was describing dependencies on one of my projects; the developer basically said that he used a dependency management system that didn’t store the components with the source code. I’ve been writing software for awhile now and while open source makes it easier to get things done, many developers don’t consider the entire build process or risks involved in not having control over all the components.

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