Install

You need opam, OCaml’s package manager, OCaml 5.5 or later, and a Postgres to keep the jobs in. spool brings dune, the build tool, with it.

1. Install opam

macOS

brew install opam

Linux

bash -c "sh <(curl -fsSL https://opam.ocaml.org/install.sh)"

2. Set up OCaml

opam init
eval $(opam env)

Answer yes when opam init offers to set up your shell. It installs the latest OCaml, which takes a few minutes; eval $(opam env) lets this terminal see it, and a new terminal does by itself.

Already had opam?

Check ocaml -version. If it is older than 5.5, make a switch – an environment of its own – with the latest OCaml:

opam switch create spool ocaml-base-compiler
eval $(opam env)

3. Install spool

opam repo add hypha https://github.com/hyphatech/opam-repository.git
opam install spool rowtype-migrate

spool brings the libraries it runs over: rowtype and its Postgres backend, rowtype-postgres, and wiretype, which describes a job’s payload. rowtype-migrate is the command that makes spool’s table, beside your own.

A program names the libraries it uses in its dune file:

(libraries spool rowtype-postgres eio_main)

Check it worked

$ ocaml -version
The OCaml toplevel, version 5.5.1

$ opam list spool

It lists spool with a version, not --, under Installed. OCaml 5.5 or later and an installed spool mean you are ready.

Your editor

For completion, types on hover and errors as you type, install the language server, then the OCaml Platform extension in VS Code – or the OCaml support of your editor:

opam install ocaml-lsp-server

The quick start runs a whole program, next.