Moving from drake to targets: package management and documentation recommendations

[jennysjaarda]

Hello! I'm very excited to finally be migrating from drake to targets and had a few questions:

(1) In my drake projects, I had been using workflowr to document my project and share with collaborators. It worked well, but I essentially updated and ran Rmd files completely independent of the drake pipelines, using loadd and readd to show results and having drake to the bulk of the analysis (i.e. no major/expensive analyses were happening in the Rmd file). With targets, I see there is the tar_render which is possibly a better option. Do you see these two packages as compatible? Also how do you recommend integrating the new Target Markdown features into the workflow with multiple report files? I'm struggling to see what exactly the new feature adds over just creating Rmarkdown files and using tar_render. Any suggestions and advice would be welcome!

(2) I previously was using packrat to manage my project packages. I've seen you also discuss renv. Would this be a better option for use with targets?

Thanks in advance for your suggestions.

Jenny

[wlandau]

tarchetypes::tar_render() is like drake::knitr_in(). It allows you to write reports as small pieces of a pipeline that automatically re-render when the upstream targets change. These reports are usually small one-page documents mainly for summarizing upstream computations. Target Markdown, on the other hand, tries to be more comprehensive. I have not personally tried it yet with a multi-page project with bookdown or workflowr, but in theory it should be easier to work into longer book-like workflows. For example, you could distribute your target definitions over multiple chapters and then have another chapter or chapters later on to run the pipeline and load the results. Alternatively, you could have multiple reports that just write the scripts to define the pipeline, and you could call tar_make() etc. outside the literate programming documents. The specific usage patterns are still in flux, but I think there is room to find out what works for you.

I would definitely recommend renv over packrat. Both are compatible with targets, but renv is much more efficient. You might have a look at targets::tar_renv(), which generates a script file to make hidden package dependencies more explicit for a project.