Tidymodels + DVC

This repository contains an example project showcasing how to use DVC alongside of tidymodels.

Full commentary is available here: https://loppsided.blog/posts/2020-10-26-tidymodels-dvc-mashup/

There are a couple of core ideas:

1. R Markdown is used as the main driver of model fitting and analysis. As such, the DVC "pipeline" consists of a single step, render::rmarkdown.

2. Within the R Markdown document, some parts of the tidymodels workflow are controlled automatically using tune, but other hyper-parameters are set explicitly using DVC parameters.

3. DVC tracks the parameters, the experiment outputs (metrics), and the input data (in this case a simple csv file).

4. GitHub Actions, along with CML, are used to fit new models and create metric rich PRs. The flow is: update params or the RMD and open PR, GA runs the DVC pipeline to fit models and create and commit the output, summary metrics are presented in a PR comment.

To view an example, take a look at the PRs on the repo.

A few things that could be improved or made more realistic:

• I don't do anything with the model. The model could be saved as an RDS object and pushed somewhere with DVC.
• The report HTML could be published to a more visible location.
• The renv plumbing is a bit awkward, see render-it.R for the wrapper. Yay for Package Manager binaries(!) but there is still a bit of manual troubleshooting to get the appropriate system requirements in place. Perhaps we could use the Package Manager system requirements API. It'd be nice if https://github.com/r-lib/actions has an action designed for running R code not testing R packages.
• The actual modeling exercise is a bit weak. I couldn't get the stacks package to work and, of course, the model itself is a bit sketchy; esp the pre-processing recipe!