Last year we had a look at managing local groups with the custom groups promise type. As you may or may not recall, we used JSON-strings to imitate CFEngine bodies. This was due to the fact that the promise module protocol did not support bodies at that time. Today, on the other hand, we’re happy to announce that as of CFEngine 3.20, this will no longer be the case. In this blog post we’ll introduce the long awaited feature; custom bodies. We’ll have a look at it from both the policy writers- and the promise module developers point of view.
Manually managing groups on a large infrastructure can be a tedious task, and is therefore best suited through automation software like CFEngine. Unfortunately - at time of writing - CFEngine does not have any built-in promise types for managing groups. But fear not; in CFEngine 3.17, custom promise types were introduced. This new exhilarating feature does not only allow for members of our community to make their own custom promise types, but also lets the CFEngine Core developers prototype new future promise types. In this blog post, I’d like to introduce one of our prototypes; the experimental groups promise type.
I recently had a minor task involving changing an option - on one of our command line tools - from taking a required argument, to taking an optional argument. This should be easy they said; just change the respective option struct to take an optional argument, add a colon to the optstring, and get on with your life.
Well, it proved to be easier said than done. My initial expectation was that a solution similar to the one below should just work. And it does work, just not in the way I expected.
