Parallel Development

Now that I'm using git, I have powerful new options available for working on projects, like spawning as many single-feature development branches as I feel like. Today I spun one off and started overhauling the Carrot status system.

The first problem was that there were a lot of statuses, and while referring to them by numeric id sounds cool (it works for Apache), it's a little less than ideal when you're reusing ids between modules. I wrote the damn thing, and I was constantly having to refer to a wiki page to tell me what statuses meant. This has been (partly) fixed by moving the lists of statuses into the modules themselves, in a __DATA__ segment which populates a hashref at constructor time.

The other part of the fix is that statuses are no longer set by passing the 'status' method a number and having that be that. This had all the problems from the above paragraph, plus a complete lack of validity checking. Now statuses are set by passing the short "name" value which acts as a key on the statuses hashref. This makes status changes much more clear (status('EBADPERMS') vs. status(103)), and now passing an undefined name to status causes an abend.

A side-effect of this is that the code is now self-documenting with respect to its statuses, and the list of statuses can't get out-of-sync without the code exploding.

Lastly, the notion of a status being set has been divorced from the notion of something having gone wrong. Several of the Carrot modules now have non-error statuses beyond '0' for "still running" and '1' for "all done" (and, as a side note, '1' is no longer consistent for that -- this needs cleanup and '99' should be the new standard for "ops complete"). Since error statuses start at code 100, the status method now sets an error flag when a code above 99 is set. Soon, all modules will be updated to halt and return undef on error instead of on status.

EDIT: ONE YEAR ANNIVERSARY OF CARROT BLOG AND THE RESTART OF SERIOUS DEVELOPMENT

(...so far yet to go...)