Circle CI as alternative to Travis for macOS builds

I just noticed that Circle CI has macOS builders. They didn’t have this last time I checked. It looks like it might be free to open-source projects.

It’s no secret that travis-ci doesn’t have enough macOS machines for the existing demand. For PyStan 2.17 it took a week to build the macOS release.

They say this:

We offer a total of four free linux containers ($2400 annual value) for open-source projects. Simply keeping your project public will enable this for you!
We also offer the Seed plan free for OS X open-source projects. Contact us at for access. If you are building a bigger open-source project and need more resources, let us know how we can help you!

Any idea if they do Windows? It’d be nice to get a single solution that’d work for all three platforms.

They don’t offer windows support.

Appveyor does windows (only) and has been great so far.

Separating out Windows makes sense because the build and test
instructions are really different. macOS and Linux can share build and
test instructions.

We have mac, linux, and windows infrastructure with Jenkins. We can’t use any of these online services for 100% of our testing, because of the distribution tests. I would personally be more inclined to make sure we cover our bases in a single system. At some point we can start adding additional compute via EC2, though we will run out of credits at some point.

I think our priorities shold be robustness to user jobs (not timing out, ideally elastic availability) and ease of maintenace. We only have so many maintenace cycles, so that’s a hard bound, but we do have $ we can throw at the problem.