This is a set of scripts and build definition files for building Firedrake as an Apptainer container. The containers are composed in layers, to avoid the need to completely rebuild the entire image for any changes. It starts by building a base image containing OpenMPI (for compatibility with the Apptainer MPI methods), and the rest of the build dependencies required for Firedrake, including the Intel MKL as the BLAS implementation. For ease of compatibility with the Bind MPI model, this is based on a Docker image that's close to the target operating system. The next layer is simply the base Firedrake build itself, which can use a vanilla build, or a cached/customisable build script. Finally, Firedrake, and optionally OpenMPI and MKL are packaged into a fresh image without the full suite of build dependencies. Particularly in the case where host libraries are bound into the container, this gives a smaller image that is more flexible.
With all the build dependencies in place, Firedrake can be built with
the unmodified upstream firedrake-install script. To update this
container, another layer can be composed, where the firedrake-update
script is run, which avoids re-downloading all the dependencies. As an
alternative to this approach, particularly during development it may
be the case that the base install is required several times. To avoid
repeated clones of the full dependency set, a script is provided to
perform these clones on the build system, along with a modified build
script that makes use of these (which are bound into the container
during build time).