build matrix contains a slightly more advanced pipeline:


let weekly = Current_cache.Schedule.v ~valid_for:(Duration.of_day 7) ()

(* Run "docker build" on the latest commit in Git repository [repo]. *)
let pipeline ~repo () =
  let src = Git.Local.head_commit repo in
  let base = Docker.pull ~schedule:weekly "ocaml/opam2" in
  let build ocaml_version =
    let dockerfile =
      let+ base = base in
      dockerfile ~base ~ocaml_version
    in ~label:ocaml_version ~pull:false ~dockerfile src |>
    Docker.tag ~tag:(Fmt.strf "example-%s" ocaml_version)
  Current.all [
    build "4.07";
    build "4.08"

The Docker.pull step shows the use of a schedule. In this case, we consider a pulled image to be valid for one week; after that OCurrent will automatically run the docker pull again to check for newer versions.

It uses Current.all to build against different versions of OCaml, generating a suitable Dockerfile for each version (the ocaml/opam2 image contains multiple versions of the compiler and the Dockerfile just selects one of them).

The generated images are then tagged with the compiler version used to build them.