Sharing Packages

Private Sharing

opam-bin provides a simple way to share the binary packages with other users and computers: it automatically creates an opam repository with the binary packages that are created. The repository is located in ~/.opam/plugins/opam-bin/store/repo and the corresponding archives are in ~/.opam/plugins/opam-bin/store/archives.

By sharing the directory ~/.opam/plugins/opam-bin/store/ with other computers, you can simply reuse your binary packages. Here is such an example session:

opam-bin clean
opam switch create 4.07.1
opam install alt-ergo -y
rsync -auv --delete ~/.opam/plugins/opam-bin/store other-computer:/tmp/
rsync -auv --delete ~/.opam/plugins/opam-bin/cache other-computer:/tmp/
ssh other-computer
$ opam remote set-url default --all --set-default file:///tmp/store/repo
$ opam switch create --empty
$ opam install alt-ergo+bin

Note that we also add to share ~/.opam/plugins/opam-bin/cache on the other computer, because without specific configuration, the url { src: } field in generated opam files will not provide the correct path to the archive. Fortunately, opam is able to use the cache to find the archives.

Public Sharing

If you want to share your binary packages on a public repository, it requires almost no additional work: you only need to specify the URL of your web-server in an option:

opam-bin config --base-url

This command will not only change the configuration for newly created packages, but also modify already generated binary packages to use this URL for the url { src: } field.

After this command, the repository is expected to be copied in, while archives are expected to be available in

opam-bin also provides a simple way to copy the repository on the remote server. You first need to specify where the files should be copied, and then use the opam-bin push command:

opam-bin config --rsync-url
opam-bin push

By default, this opam-bin push will delete all upstream packages that are not locally present. It will also generate in the repository a file index.tar.gz for opam, and a file index.html listing all available packages.

If you don’t want this behavior, i.e. you only want to merge new packages, you should use the --merge option, you will also need to recreate the file index.tar.gz upstream:

opam-bin config --rsync-url
opam-bin push --merge
$ cd /var/www/opam-bin/repo
$ opam admin index

Yet, most of the time, you will want to build your packages on top of former binary packages, so you may want to first download your upstream repo locally, so that you will be able to avoid the --merge option. For that, you can use opam-bin pull. For example, if you want to add a binary package for alt-ergo and its dependencies:

opam-bin config --rsync-url
opam-bin pull
opam install alt-ergo -y
opam-bin push

It is possible to customize the header and trailer of the generated index.html file by defining the files ~/.opam/plugins/opam-bin/header.html and ~/.opam/plugins/opam-bin/trailer.html. To test the impact of changing these files, you can use:

opam-bin push --local-only

to generate a new ~/.opam/plugins/opam-bin/store/repo/index.html file and check the result.

Using a Binary Repository Only

Once a repository with binary packages has been published, opam-bin is not needed to use it.

For example:

export OPAMROOT=$HOME/opam-root
opam init --bare -n
opam switch create alt-ergo --empty
opam install alt-ergo -y