OBuilder - Homogeneous builds with OBuilder and OCaml

This talk will present a lightweight sandboxing solution OBuilder that works beyond the usual Linux containerisation solutions, providing support for macOS, Windows and the BSDs without requiring full (expensive) virtualisation. We will cover the implementation for macOS and Windows, the challenges encountered with providing sandboxes on such different platforms, and how this work is being used to provide multi-platform builds to the OCaml community.

We previously introduced OCaml-CI (OCaml Workshop 2020 “OCaml-CI : A Zero-Configuration CI”) providing an opionated, fast-feedback CI system for OCaml projects. Since the end of 2020, opam-repo-ci has provided a similar service for testing pull requests to opam-repository and opam-health-check checks for broken opam packages across OCaml versions. All of these systems use OBuilder to provide support across multiple operating systems and hardware architectures.