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dune-release: release dune packages in opam

dune-release is a tool to streamline the release of Dune packages in opam. It supports only projects be built with Dune and released on GitHub.


dune-release can be installed with opam:

opam install dune-release


The dune-release command line tool is extensively documented in man pages available through it's help system. Type:

dune-release help release # for help about releasing your package
dune-release help         # for more help

Calling dune-release without any argument will start the automated release process, composed of the following steps:

  • create the distribution archive;
  • publish it online with its documentation;
  • create an opam package;
  • submit it to OCaml's opam repository.

If the repository contains multiple opam packages, dune-release will try to release all of them by default (ie. one tarball, one github release but several opam files added to the opam repository).

The most basic workflow is:

dune-release tag

Each step is refined and explained with more details below. By default dune-release asks for permission before taking any significant action so you should not be afraid of running it.

Tag the distribution with a version

This step should be executed prior to running the dune-release automated process.

The tagging command of dune-release will extract the latest version tag from the package's change log and tag the VCS HEAD commit with it if it is invoked without argument:

dune-release tag

This will only work if the change log follows a certain format. The version number must be in the first item of the change log file (usually a section title). Asciidoc and Markdown files are supported. A typical example of such version in a markdown file is:

## v1.0.1 (2019-09-30)

The version extracted from this change log will be v1.0.1. This will be used to infer the tag of the release as well as generate the publication message. If you do not want to rely on this extraction you can specify it on the command line:

dune-release tag v1.0.1

You can also directly use your VCS instead if the dune-release tag command does not fit your needs. Note that dune-release and dune only work with annotated tags (i.e. tags created with git tag -a) and that if you want to take care of the tagging yourself you should take this into account.

If you need to delete a tag created by dune-release, use the following command:

dune-release tag -d v1.0.1

The full documentation of this command is available with

dune-release help tag

Create the distribution archive

Now that the release is tagged in your VCS, generate a distribution archive for it in the build directory with:

dune-release distrib

This uses the source tree of the HEAD commit for creating a distribution in the build directory. Note that any uncommitted change will therefore be ignored. The distribution version string is the VCS tag description (e.g. git-describe) of the HEAD commit. Alternatively it can be specified on the command line.

Basic checks are performed on the distribution archive when it is created, but save time by catching errors early. Hence test that your source repository lints and that it builds in the current build environment and that the package tests pass.

dune-release lint
dune build # Check out the generated opam install file too
dune runtest

The full documentation of this command is available with

dune-release help distrib

Publish the distribution and documentation online

Once the distribution archive is created you can now publish it and its documentation online.

You can publish the archive only with:

dune-release publish distrib

This means creating a Github release associated with the tag and upload the distribution tarball as a release artifact.

You can publish the documentation only with:

dune-release publish doc

This means publishing the dune generated documentation to gh-pages to be served as a static website on

If neither distrib neither doc is specified, dune-release publishes both:

dune-release publish

The full documentation of this command is available with

dune-release help publish

Publish troubleshooting

If github returns a Permission denied error during dune-release publish, the reason is probably a failing ssh connection. In that case, we suggest that you set up ssh. If you prefer not to and you've already set up https instead, we suggest that you configure git as follows:

git config [--global] url."".pushInsteadOf ""

Running that line once will configure git to always push over https - either for that repository or globally.

In more detail: dune-release publish always pushes to github over ssh by explicitly giving git the github uri of your project with ssh prefix ( By configuring git as suggested above, git will automatically replace that prefix by the https one when pushing and push over https instead.

Create an opam package and submit it to the opam repository

To add the package to OCaml's opam repository, we start by creating an opam file to be used on the opam repository. This file includes the download URI for the distribution tarball and the tarball hash:

dune-release opam pkg

To submit the package to the opam repository and create the associated pull request we run:

dune-release opam submit

The full documentation of this command is available with

dune-release help opam

Important Notes

Most of the code in this repository has been written and has already been released part of the topkg tool.

The main differences between dune-release and topkg are:

  • Remove pkg/;
  • Assume the project is built with dune;
  • Bundle everything as a single binary;
  • Use of Astring, Logs, Fpath andBos;
  • Remove the IPC layer (which is used between topkg and topkg-care);

Runtime dependencies

  • bzip2 can be set with the DUNE_RELEASE_BZIP2 variable (deprecated), otherwise it is expected to be in PATH;
  • tar can be set with the DUNE_RELEASE_TAR variable (deprecated), otherwise it is expected to be in PATH;
  • git can be set with the DUNE_RELEASE_GIT variable (deprecated), otherwise it is expected to be in PATH;
  • hg can be set with the DUNE_RELEASE_HG variable (deprecated), otherwise it is expected to be in PATH;
  • opam can be set with the HOST_OS_OPAM variable (deprecated), otherwise it is looked for in HOST_OS_XBIN/opam (deprecated), otherwise it is looked for in opamHOST_OS_SUFF (deprecated), otherwise it is expected to be in PATH;
  • dune, curl, cp and ocamlfind are expected to be in PATH.

Using these DUNE_RELEASE_* and HOST_OS_* environment variables to configure the path to these binaries is deprecated since dune-release.1.4.0, and will no longer be supported in dune-release.2.0.0, it is thus recommended to only rely on the PATH variable.