If you host your analysis workflows on publicly accessible external sources such as source code repositories (GitHub, GitLab), digital repositories (Zenodo), or simply other locations on the web (generic URL), it is now possible to launch your workflows directly on the web using the brand new REANA launcher web page.
An alternative way to execute workflows
The traditional and the most-used way of executing REANA workflows is by means
of the reana-client command-line tool. You can use it to create workflows,
upload files to workspaces, start workflow execution, consult logs, download
results, and more. A short tutorial on using reana-client can be found on the
First example
documentation page.
Another, even more low-level way to manage workflows, is to use the Python API. This can be useful if you want to interact with REANA from your Python application. A short tutorial on using REANA Python API can be found in the How to run REANA workflows using Python API blog post.
Both of these approaches require installing reana-client locally, which can
be non-desirable in certain usage scenarios. For example, if you only want to
execute an already-published workflow to check its results, or re-execute it
with modified input parameters, it may be easier to launch such a workflow
using directly the web interface, saving the work of manually cloning the
repository and editing its input files. The new REANA launcher functionality
enables exactly this kind of usage scenarios.
Launching workflows using web interface
If you have a valid CERN account, please go to the reana.cern.ch/launch where you will see the launcher home page with several demo examples:
You can click on one of the presented examples to launch the workflow on the REANA web site. For example, clicking on the RooFit demo will redirect you to the following page:
where you can further click on the Launch button. REANA will then fetch the workflow from the remote GitHub repository and start its execution.
Constructing your own launch URLs
If you look at the browser address bar, you will see the following full URL before launching the RooFit demo example:
https://reana.cern.ch/launch?url=https%3A%2F%2Fgithub.com%2Freanahub%2Freana-demo-root6-roofit&name=reana-demo-root6-roofit
The launcher functionality is handled by the /launch endpoint which executes
the workflow specified by the url argument. By pointing url to where you
host your workflow, you can construct your own launch URLs for your analyses.
You can also optionally provide a custom workflow run name via a name
argument, or choose a path to a specific reana.yaml specification file via
the specification argument. Finally, you can also modify workflow’s input
parameters via specially encoded parameters argument.
For a detailed description of all launcher arguments, please see the Launcher arguments documentation page.
Using launch badges
We have prepared a set of Launch-on-REANA badges that you can use to make your workflows runnable by simply clicking on them:
Badges are just images that will redirect users to the launch URLs constructed
above. This means that you can include them wherever you want, for example in
the README file of your Git repositories.
Here is an example of a badge used in the README file of the RooFit demo
example:
For more information on available badges, please see the Launcher badges documentation page.
Availability
REANA launcher will be coming with the REANA 0.9.0 release series. The launcher functionality is already deployed for a preview on the reana.cern.ch instance. The launcher currently supports launching workflows from publicly accessible URLs only. Please give it a try and let us know what you think!
See also
- Launching workflows from external sources documentation page