This monitors a local Git repository (repo), from which it gets the current head commit. It copies it to a temporary clone and builds it with docker build /path/to/clone, then executes the example with --help to check that it runs.

$ git clone https://github.com/talex5/ocurrent.git
$ cd ocurrent/
$ dune exec -- ./examples/docker_build_local.exe .
[...]
    current [INFO] Evaluation complete:
                     Result: Pending
                     Watching: [/home/user/ocurrent/#refs/heads/master;
                                HEAD(/home/user/ocurrent/)]
[...]
current.docker [INFO] Build of docker image "build-of-d75e33fd875d80cd8e0cddf83904dd6d7aea12d3" succeeded
[...]
    current [INFO] Evaluation complete:
                     Result: Ok ()
                     Watching: [/home/user/ocurrent/#refs/heads/master;
                                HEAD(/home/user/ocurrent/)]

If you make a new commit or change branch (e.g. git checkout -b test HEAD~1) then OCurrent will notice and build it again.

The example code above works mostly with values of type 'a Current.t. For example, Docker.build takes a source current and returns a Docker image current. If you have a function that works on concrete values then you can use Current.map (or the let+ syntax) to make it work on currents instead.

You can also use Current.bind (or the let* syntax) if you can only decide what the next part of the pipeline should be by looking at a concrete input. However, using bind limits OCurrent’s ability to analyse the pipeline, because it must wait for the input to be ready before knowing what happens next.

OCurrent has a small core language (in lib and lib_term), but most functionality is added by external libraries. See the plugins directory for some examples.

The example also runs a minimal web UI on port 8080 (use --port=... to change it), showing the state of the system. You will need to have graphviz installed in order to see the diagrams.

A green box indicates a pipeline stage that succeeded, orange means in-progress, grey means cannot be started yet (inputs not ready), yellow means queued or waiting for permission to start, and red means failed.

Clicking on a box shows the log for that operation (though not all operations have logs; head commit doesn’t, for example).