Docs CI

OCaml-CI Build Status

OCaml Docs CI (aka ocaml-docs-ci or just docs-ci) is an OCurrent pipeline used to build the documentation for website. It uses the metadata from opam-repository to work out how to build documentation for individual packages using voodoo, the OCaml package documentation generator, and generates a HTML output suitable for server.


Get the code with:

git clone --recursive
cd ocaml-docs-ci

Note: you need to clone with –recursive because this project uses submodules (it depends on some packages that aren’t released yet). If you forget, git submodule update --init will fetch them.

Then you need an opam 2.1 switch using OCaml 4.14. Recommend using this command to setup a local switch just for docs-ci.

# Create a local switch with packages and test dependencies installed
opam switch create . 4.14.1 --deps-only --with-test -y

# Run the build
dune build

# Run the tests
dune build @runtest


At a high level docs-ci purpose is to compile the documentation of every package in the opamverse. To do this it generates a dependency universe. For each package (along with the version), the documentation is generated for it plus all of its dependencies. This documentation is then collected into a documentation set and provided to the service. The voodoo tool defines the on disk format for the documentation set.

For further details on how docs-ci works read the pipeline diagram.


ocaml-docs-ci is deployed as into two environments, with ocurrent-deployer. The application is deployed as a series of Docker containers from a git branch.


Environment www pipeline git branch data voodoo branch
Production live main
Staging staging staging

OAuth integration provided by GitHub OAuth Apps hosted under the OCurrent organisation. See

The infrastructure for docs-ci is managed via Ansible, contact @tmcgilchrist or @mtelvers if you need access or have questions.

To deploy a new version of docs-ci:

  1. Create a PR and wait for the GH Checks to run (ocaml-ci compiles the code and ocurrent-deployer checks it can build the Dockerfiles for the project)
  2. Test the changes on staging environment by git cherry picking the commits to that branch and pushing it
  3. Check for docs-ci

Follow a similar process for live exercising extra caution as it could impact the live service.

The git history on live and staging MUST be kept in sync with the default branch. Those branches should be the same as main plus or minus some commits from a PR.

Remote API

docs-ci has a cli tool (ocaml-docs-ci-client) for interacting with the pipeline over CapnP. It provides commands to:

The output is via json, which is intended to be combined with jq to display and query for pieces of information.

Local Development

ocaml-docs-ci is runable as:

dune exec -- ocaml-docs-ci \
    --ocluster-submission cap/XXX.cap \
    --ssh-host \
    --ssh-user docs \
    --ssh-privkey cap/id_rsa \
    --ssh-pubkey cap/ \
    --ssh-folder /data/ocaml-docs-ci \
    --ssh-endpoint \
    --jobs 6 \
    --filter mirage \
    --limit 6

A docker-compose.yml is provided to setup an entire docs-ci environment including:

Run this command to create an environment:

$ docker-compose -f docker-compose.yml up

You should then be able to watch the pipeline in action at http://localhost:8080.


Migrations are managed using omigrate. If you are using an opam switch for ocaml-docs-ci then omigrate should be installed and you can create a new migration by doing this from the project root:

$ omigrate create --dir migrations <migration-name>

This will create timestamped files in the migrations directory that you can then populate with the sql necessary to introduce and remove the migration (in the up and down files respectively).

Migrations will not run unless the –migration-path flag is present when invoking ocaml-docs-ci-service.

Epoch management

Epochs are used in ocaml-docs-ci to organise sets of artifacts all produced by the same odoc/voodoo version. There is a cli tool for managing epochs described in