Dune - A composable build system
Dune is a build system designed for OCaml/Reason projects only. It focuses on providing the user with a consistent experience and takes care of most of the low-level details of OCaml compilation. All you have to do is provide a description of your project and dune will do the rest.
The scheme it implements is inspired from the one used inside Jane Street and adapted to the open source world. It has matured over a long time and is used daily by hundreds of developers, which means that it is highly tested and productive.
The example directory contains examples of projects using dune.
Dune reads project metadata from
dune files, which are either
static files in a simple S-expression syntax or OCaml scripts. It uses
this information to setup build rules, generate configuration files
for development tools such as merlin, handle installation,
Dune itself is fast, has very low overhead and supports parallel
builds on all platforms. It has no system dependencies: all you need
to build dune and packages using dune is OCaml. You don't need
bash as long as the packages themselves don't use
Especially, one can install OCaml on Windows with a binary installer and then use only the Windows Console to build dune and packages using dune.
Take n repositories that use dune, arrange them in any way on the file system and the result is still a single repository that dune knows how to build at once.
This make simultaneous development on multiple packages trivial.
Gracefully handles multi-package repositories
Dune knows how to handle repositories containing several packages. When building via opam, it is able to correctly use libraries that were previously installed even if they are already present in the source tree.
The magic invocation is:
$ dune build --only-packages <package-name> @install
Building against several configurations at once
Dune is able to build a given source code repository against several configurations simultaneously. This helps maintaining packages across several versions of OCaml as you can test them all at once without hassle.
This feature should make cross-compilation easy, see details in the roadmap.
This feature requires opam.
Jenga is another build system for OCaml that has more advanced features such as polling or much better editor integration. Jenga is more powerful and more complex and as a result has many more dependencies. It is planned to implement a small bridge between the two so that a dune project can build with Jenga using this bridge.
Dune requires OCaml version 4.02.3 or greater.
The recommended way to install dune is via the opam package manager:
$ opam install dune
You can also build it manually with:
$ make release $ make install
Note however that
make install requires the
tool. Running simply
make will build dune using the development
If you do not have
make, you can do the following:
$ ocaml bootstrap.ml $ ./boot.exe $ ./_build/default/bin/main_dune.exe install dune
Migration from jbuilder
Dune was formerly known as jbuilder. Migration from jbuilder to dune is described in the manual.
Dune is now fairly stable and is used by the majority of packages on opam. The package is still in beta version as we are waiting for the renaming from Jbuilder to dune before releasing version 1.0.0. Note that dune will have backward compatibility with Jbuilder, in particular existing Jbuilder projects will continue to be buildable with dune.