Hey HN, we are happy to announce Modus, a language for building Docker/OCI container images. Modus uses logic programming to express interactions among build parameters, specify complex build workflows, automatically parallelise and cache builds, help to reduce image size, and simplify maintenance. Modus is distributed under AGPL-3.0. The current version, 0.1, is a preview release; it is not recommended for production use. Feedback is welcome!