To make this concrete: terraform for me has been part code, part configuration.
I define a resource, and provide a whole set of knobs on that resource. That's the code part. I test that code against a variety of configurations, the same way I might unit test application code against a variety of app configurations. I also verify that changing knobs from one setting to another behaves. With automated testing, this actually isn't all that hard to do. Once I've verified things work right, I deploy.
At this point, I will default to trusting that things will work. This is the configuration part. Set these knobs to whatever permitted value you want, and the system will update behavior based on those new values. Most of the time, things like this work. That is good enough for me.
I define a resource, and provide a whole set of knobs on that resource. That's the code part. I test that code against a variety of configurations, the same way I might unit test application code against a variety of app configurations. I also verify that changing knobs from one setting to another behaves. With automated testing, this actually isn't all that hard to do. Once I've verified things work right, I deploy.
At this point, I will default to trusting that things will work. This is the configuration part. Set these knobs to whatever permitted value you want, and the system will update behavior based on those new values. Most of the time, things like this work. That is good enough for me.