Conda-build 3 May Change Everything

[Lnaden]

Conda-build 3 is a major change to the way builds are handled. For instance, it looks like single meta.yaml files can build multiple versions of Python in one go. We may even be able to vastly simply if not outright remove our "conda-build-all" script.

Because of the major changes conda-build 3 will introduce, and some build issues we are seeing on our local packages, I am going to pin the conda-build version to 2.1.17 (last of the 2 series) until we can properly use conda build 3.

This issue should stay open until we can use conda build 3.

additional reading: https://conda.io/docs/building/variants.html

[Lnaden]

I have started delving into the new Conda-Build, and it looks like it may simplify some things, but make our name checking to see if the package already exists tricky.

Instead of names like {package}{build}_py{pyver}np{numpy}.tar.gz, it hashes the suffix since it generalizes the pinning process. The result is you can have x.x requirements on any package, but outputs the file name to {package}{build}_py{ver}{hash}.tar.gz, which means that every single package would have to be rebuilt once and uploaded.

I'm also still trying to figure out how we reduce build duplication since each build is now considered a variant, which is hard to aggregate over many many packages while also checking for the package already existing on the cloud.

Has anyone else tried using conda-build 3 for multiple package/variant builds yet?